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Objective:To investigate the mechanism of extract of ginkgo biloba (EGB) on mitochondrial autophagy in breast cancer cells MCF-7.Methods:Breast cancer MCF-7 cells were divided into four groups. EGB with mass concentrations of 40, 80, 120 mg/L was used to incubate breast cancer MCF-7 cells for 24 h or 48 h, as a low concentration group of EGB, a medium concentration group of EGB, and a high concentration group of EGB. Breast cancer MCF-7 cells without intervention were taken as control group. Cell proliferation was measured using MTT assay; Flow cytometry was used to detect cell apoptosis; Immunofluorescence assay was used to determine the contents of prostacyclin (P62), microtubule-associated protein light chain 3Ⅱ (LC3Ⅱ), and caspase-3; The levels of multidrug resistance-associated protein 1 (MRP1), multidrug resistance gene 1 (MDR1) and breast cancer resistance protein (BCRP) were identified by PCR; Western blotting was used to detect the expression of extracellular signal-regulated kinase (ERK), mitogen-activated protein kinase (MAPK), p-ERK, and p-MAPK proteins in cells.Results:The results of MTT assay for cell proliferation showed that cell proliferation at 24 h in control group, EGB low, medium and high concentration groups were 0.95±0.14, 0.65±0.09, 0.51±0.07, 0.37±0.04, respectively, with a statistically significant difference ( F=43.13, P<0.001), cell proliferation at 48 h were 1.32±0.19, 0.54±0.08, 0.32±0.05, 0.15±0.02, respectively, with a statistically significant difference ( F=141.30, P<0.001). Compared with 24 h, cell proliferation was decreased in EGB low, medium and high concentration groups at 48 h (all P<0.05). Pairwise comparison showed that EGB treatment significantly decreased MCF-7 cell viability and cell proliferation was decreased in turn at 24 and 48 h in control group, low, medium, high EGB groups (all P<0.05). Flow cytometry analysis revealed that the apoptosis rates of MCF-7 cells in control group, EGB low, medium and high concentration groups were 2.12%±0.23%, 9.28%±0.45%, 15.17%±1.28% and 22.21%±2.32%, respectively, with a statistically significant difference ( F=128.80, P<0.001). Pairwise comparison showed that the apoptosis rate of control group, EGB low, medium and high concentration groups were increased in turn (all P<0.05). The results of immunofluorescence assay showed that the protein relative expression levels of P62 protein in MCF-7 cells of control group, EGB low, medium and high concentration groups were 3.34±0.52, 2.85±0.47, 2.02±0.18 and 1.08±0.21, respectively, with a statistically significant difference ( F=41.55, P<0.001). LC3Ⅱ protein relative expression levels were 0.24±0.05, 1.02±0.14, 1.47±0.26, 1.95±0.21, respectively, with a statistically significant difference ( F=94.82, P<0.001). The relative expression levels of caspase-3 protein were 0.25±0.03, 0.68±0.21, 1.12±0.17 and 1.65±0.23, respectively, with a statistically significant difference ( F=68.09, P<0.001). Pairwise comparison showed that LC3Ⅱ and caspase-3 protein expression levels were increased in turn in control group, EGB low, medium and high concentration groups, while P62 protein expression levels were decreased in turn (all P<0.05). The PCR experiment results showed that the MRP1 mRNA level of MCF-7 cells in control group, EGB low, medium and high concentration groups were 1.06±0.14, 0.83±0.18, 0.71±0.11, 0.52±0.08, respectively, with a statistically significant difference ( F=17.41, P<0.001). The mRNA levels of MDR1 were 1.14±0.17, 0.75±0.13, 0.60±0.09, 0.48±0.06, respectively, with a statistically significant difference ( F=34.40, P<0.001). BCRP mRNA levels were 1.09±0.11, 0.88±0.13, 0.69±0.07, 0.57±0.05, respectively, with a statistically significant difference ( F=34.13, P<0.001). Pairwise comparison showed that the levels of MRP1, MDR1 and BCRP mRNA were decreased in turn in control group, EGB low, medium and high concentration groups (all P<0.05). The results of Western blotting showed that the expression of ERK in MCF-7 cells in control group, EGB low, medium and high concentration groups were 2.54±0.38, 1.89±0.25, 1.55±0.21, 1.12±0.16, respectively, with a statistically significant difference ( F=31.18, P<0.001). MAPK expression were 2.47±0.34, 1.96±0.29, 1.63±0.27, 1.20±0.24, respectively, with a statistically significant difference ( F=20.90, P<0.001). p-ERK expression were 2.03±0.29, 1.74±0.21, 1.45±0.11, 1.18±0.24, respectively, with a statistically significant difference ( F=16.31, P<0.001). p-MAPK expression were 2.26±0.47, 1.90±0.41, 1.61±0.33, 1.35±0.16, respectively, with a statistically significant difference ( F=7.01, P=0.002). Pairwise comparison showed that the expressions of ERK, MAPK, p-ERK and p-MAPK in control group, EGB low, medium and high concentration groups were decreased in turn (all P<0.05) . Conclusion:EGB can inhibit the proliferation of breast cancer MCF-7 cells, promote the apoptosis of MCF-7 cells, decrease the expression of P62 protein, increase the expression of LC3Ⅱ and caspase-3 protein, induce mitochondrial autophagy.
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BACKGROUND:Bushen Yiqi Huayu granule has the effect of replenishing qi and eliminating blood stasis,tonifying kidney and smoothing collages,and is often used in the treatment of osteoporosis.At present,there are few studies on the effect of Bushen Yiqi Huayu granule on the callus angiogenesis of osteoporotic fractures. OBJECTIVE:To explore the mechanism of Bushen Yiqi Huayu granule by up-regulating extracellular signal-regulated kinase/mitogen-activated protein kinases(ERK/MAPK)signaling pathway to improve callus angiogenesis after fracturing in osteoporotic rats. METHODS:(1)Bone marrow mesenchymal stem cells from osteoporotic SD rats and bone marrow monocytes from C57BL/6 mice were collected.MTT assay was used to detect different doses of Bushen Yiqi Huayu granule on bone mesenchymal stem cell toxicity.Bone mesenchymal stem cells and bone marrow monocytes were cultured in the medium supplemented with 0 and 1.5 mg/mL Bushen Yiqi Huayu granules,respectively,and osteogenic differentiation and osteoclast differentiation were carried out in vitro.(2)144 SD rats were randomly divided into sham operation group,model group,granule group and granule+PD98059 group with 36 rats in each group.The osteoporotic model was established in the model group,granule group and granule+PD98059 group,and only part of the adipose tissue near the ovary was removed in the sham operation group.8 weeks later,all rats received left tibial osteotomy.In the granule+PD98059 group,5 g/kg Bushen Yiqi Huayu granule was given intragastrically,and 0.3 mg/kg PD98059 was injected into the tail vein.The granule group was given 5 g/kg Bushen Yiqi Huayu granule,and the same volume of normal saline was injected into the tail vein.The sham operation group and model group were given an equal volume of normal saline,and the caudal vein was injected with an equal volume of normal saline.Drug administration was conducted once a day for 8 weeks.Fracture healing and callus angiogenesis were observed by X-ray,micro-computed tomography and microvascular perfusion angiography.Bone mineral density and mechanical strength of the callus were measured.The tibia was observed by hematoxylin-eosin staining and Masson staining.Western blot assay and immunohistochemistry were used to examine the expression of ERK/MAPK signaling pathway-related molecules. RESULTS AND CONCLUSION:(1)Compared with the 0 mg/mL group,the alkaline phosphatase activity,mineralization level,p-ERK1/2 and p-p38 MAPK expression levels of osteocytes increased(P<0.05),while the density and volume of osteoclasts decreased in the 1.5 mg/mL group(P<0.05).(2)Compared with the sham operation group,the fracture healing degree of the granule group was similar at 4 and 8 weeks,but there was no significant difference in Lane-Sandhu score,total callus volume,mineralized callus volume,mineralized callus volume/total callus volume,trabecular thickness,vascular number,spacing,thickness,vascular volume/total volume,bone mineral density,ultimate load of callus,stiffness,p-ERK1/2,p-p38 MAPK,p-IκB-α,and p-p65 expression levels(P>0.05).In the model group and granule+PD98059 group,fracture healing was slow,Lane-Sandhu score,total callus volume,mineralized callus volume,mineralized callus volume/total callus volume,trabecular thickness,vascular number,thickness,vascular volume/total volume,bone mineral density,ultimate load of callus,stiffness,p-ERK1/2,p-p38 MAPK,p-IκB-α,and p-p65 expression levels decreased(P<0.05),and vascular spacing increased(P<0.05),compared with the sham operation group.(3)It is indicated that Bushen Yiqi Huayu granule can improve fracture healing,promote callus angiogenesis and alleviate the symptoms of osteoporosis by enhancing the expression of the ERK/MAPK signaling pathway-related molecules in osteoporotic rats.
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ObjectiveTo explore the possible mechanism of Pingwei Capsules (平胃胶囊) for chronic atrophic gastritis from rapidly accelerated fibrosarcoma / mitogen-activated protein kinase /extracellular-signal-regulated kinase (Raf/MEK/ERK) pathway that influences the activation of fibrosarcoma protein/mitogen. MethodsFifteen SD rats were randomly divided into 5 rats in the blank group and 10 rats in Pingwei Capsules group. The rats in the blank group were given 1 ml/100 g of saline by gavage, and the rats in Pingwei Capsules group were given 0.63 g/(kg·d) of Pingwei Capsule suspension by gavage, and serum was collected for 3 consecutive days. N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) was used to induce human gastric mucosal epithelial cells GES-1 to establish a precancerous lesion cell model. The successful cells were divided into control group (10% fetal bovine serum), blank serum group (10% fetal bovine serum plus 10% blank serum), and medication-containing serum group (serum with medication of Pingwei Capsule), and the volume fraction and time of intervention of Pingwei Capsule-containing serum were screened by CCK-8 assay. Human gastric mucosal epithelial cells GES-1 were divided into normal group, model group, blank serum group, medication-containing serum group, U0126 group, and combined group, with 6 replicate wells in each group. After successful modelling of the cells in all groups except the blank group, an equal volume of fetal bovine serum was added to the normal and model groups, an equal volume of blank serum was added to the blank serum group, a screening volume fraction of Pingwei Capsule-containing serum was added to Pingwei Capsule group, a 10 μmol/L mitogen-activated extracellular signal regulated kinase 1 (MEK1) inhibitor U0126 was administered in the U0126 group, an equal dose of Pingwei Capsule-containing serum plus 10 μmol/L of U0126 was administered to the combined group. After the selected incubation time, the level of interleukin 6 (IL-6) was detected in the cells by ELISA, the expression of IL-6 and MEK1 was detected by immunofluorescence, and the expression of IL-6, Raf, MEK1, and ERK mRNA was detected by RT-qPCR, and the expression of IL-6, Raf, MEK1, and ERK mRNA in the cells was detected by Western blot. ResultsThe 5.35% volume fraction, 48 h intervention of Pingwei Capsule-containing serum was selected for subsequent experiments. Compared with the normal group, the IL-6 content in cell supernatants and the expression of IL-6, Raf, MEK1, ERK mRNA and ERK1/2 proteins in cells increased in the model group and blank serum group (P<0.01). Compared with the model group, all of the above indexes were improved in medication-containing serum group, U0126 group, and combined group (P<0.05 or P<0.01). Compared with medication-containing serum group, the expression of IL-6, MEK1 expression, the expression of IL-6, Raf, MEK1 and ERK mRNA, and the expression of IL-6, Raf, MEK1 and ERK1/2 proteins reduced in the cells of combined group (P<0.05 or P<0.01). Compared with the U0126 group, IL-6 expression reduced and IL-6, MEK1 and ERK1/2 protein expression reduced in cells of combined group (P<0.05 or P<0.01). ConclusionThe Pingwei Capsule-containing serum may play a role in the treatment of chronic atrophic gastritis by improving the inflammation-cancer transformation of GES-1 cells through inhibiting the Raf/MEK/ERK pathway.
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ObjectiveTo investigate the role and mechanism of Hei Xiaoyaosan in intervening in oxidative stress in the rat model of Alzheimer's disease (AD) via modulating the rat sarcoma (RAS)/rapidly accelerating fibrosarcoma (RAF)/mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling pathway. MethodOne hundred 4-month-old SPF-grade Wistar male rats were randomly grouped as follows: 10 in the blank group, 10 in the sham group (bilateral hippocampus injected with 1 μL normal saline), and 80 in the modeling group [bilateral hippocampus injected with 1 μL amyloid beta protein 1-42 (Aβ1-42) solution for the modeling of AD]. Fifty rats qualified for modeling were selected and randomized into the model, donepezil hydrochloride (0.5 mg·kg-1), and high-, medium-, and low-dose (15.30, 7.65, 3.82 g·kg-1, respectively) Hei Xiaoyaosan groups. The rats were administrated with corresponding drugs by gavage once a day for 42 consecutive days. At the end of gavage, Morris water maze test was performed to examine the learning and memory abilities of the rats, and Nissl staining was used to observe the pathological changes of neurons in CA3 region of the hippocampus. The immunofluorescence assay was used to observe Aβ deposition and tau phosphorylation. Western blot was employed to determine the protein levels of RAS, RAF, phosphorylated (p)-RAF, MEK, p-MEK, ERK, and p-ERK in the hippocampal tissue. Biochemical methods were used to determine the levels of reactive oxygen species (ROS), malondialdehyde (MDA), and superoxide dismutase (SOD) in the hippocampal tissue. ResultCompared with the sham group, the model group showed prolonged escape latency (P<0.01), shortened swimming distance in the target quadrant (P<0.01), reduced and uneven stained Nissl bodies, enhanced fluorescence intensity of Aβ and p-tau (P<0.01), up-regulated protein levels of RAS, p-RAF, p-MEK, and p-ERK in the hippocampal tissue (P<0.01), increased ROS and MDA content (P<0.01), and decreased SOD activity (P<0.01) on day 5. Compared with the model group, donepezil hydrochloride and high-, medium-, and low-dose Hei Xiaoyaosan shortened the escape latency (P<0.01), increased the swimming distance in the target quadrant (P<0.01), improved the arrangement, morphology, and structures of neurons and the number and distribution of Nissl bodies, decreased the fluorescence intensity of Aβ and p-tau (P<0.01), up-regulated the protein levels of RAS, p-RAF, p-MEK, and p-ERK (P<0.05, P<0.01), decreased the ROS and MDA content (P<0.01), and increased the SOD activity (P<0.01) on day 5. ConclusionHei Xiaoyaosan may ameliorate oxidative stress, reduce Aβ and p-tau levels, and inhibit hippocampal neuronal damage by regulating the RAS/RAF/MEK/ERK signaling pathway, thus improving learning and memory abilities.
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ObjectiveTo decipher the mechanism of Wenxiao powder in alleviating corticosterone-induced depression-like behaviors in mice. MethodMale ICR mice were randomized into normal, model, paroxetine (20 mg·kg-1), and low- and high-dose (3.27, 6.54 g·kg-1, respectively) Wenxiao powder groups. The mice in normal and model groups received equal volume of saline. Other groups except the normal group were injected with corticosterone subcutaneously 0.5 h after gavage to induce depression. Mice were tested for depression-like behaviors after drug administration. Enzyme-linked immunosorbent assay (ELISA) was performed to measure the corticosterone content in the serum. Nissl staining was performed to observe the damage of hippocampal neurons. Immunofluorescence staining was employed to observe the expression of double cortin (DCX) in the dentate gyrus (DG) of the hippocampus. Western blot was employed to determine the expression of proteins in the brain-derived neurotrophic factor (BDNF)/tyrosine kinase receptor B (TrkB)/extracellular signal-regulated kinase (ERK)/cAMP-response element-binding protein (CREB) pathway in the hippocampus. ResultCompared with the normal group, the model group showed decreased sucrose preference rate, increased immobility time in the tail suspension test (P<0.01), and reduced residence time in the central area of the open field and the total movement distance (P<0.05, P<0.01). In addition, the modeling elevated the corticosterone level in the serum (P<0.01), decreased the volume and intensified the nuclear staining of hippocampal neurons in the DG area, reduced the expression of DCX in the DG area, and down-regulated the protein levels of BDNF, phosphorylated (p)-TrkB, p-ERK, and p-CREB in the hippocampus (P<0.05, P<0.01). Compared with the model group, low-dose Wenxiao powder improved the mouse behavivors in the sucrose preference, open field, and tail suspension tests (P<0.05, P<0.01), and high-dose Wenxiao powder improved the behaviors in the sucrose preference and open field tests (P<0.05, P<0.01). In addition, Wenxiao powder lowered the serum corticosterone level (P<0.01) and recovered the structure and morphology of neurons with obvious nuclei and presence of Nissl bodies in the DG area of the hippocampus. Moreover, Wenxiao powder at both doses promoted the expression of DCX in the DG area, and high-dose Wenxiao powder up-regulated the protein levels of BDNF, p-TrkB, p-ERK, and p-CREB in the hippocampus (P<0.05, P<0.01). ConclusionWenxiao powder can alleviate corticosterone-induced depression-like behaviors and promote neurogenesis in mice possibly by activating the BDNF/TrkB/ERK/CREB signaling pathway.
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ObjectiveTo explore the effect and mechanism of the classic famous prescription Anmeidan (AMD) developed in the Qing Dynasty in regulating the hepatic neurotransmitters and circadian rhythm in the rat model of insomnia via the orexin-1 receptor (OX1R)/phosphatidylinositol-specific phospholipase Cβ-1 (PLCβ-1)/protein kinase Cα (PKCα)/extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway. MethodSixty SPF-grade SD rats were randomized into blank, model, suvorexant (30 mg·kg-1·d-1), and low-, medium-, and high-dose (4.55, 9.09, 18.09 g·kg-1·d-1, respectively) AMD groups, with 10 rats in each group. The rats in other groups except the blank group were modeled by intraperitoneal injection of p-chlorophenylalanine (PCPA) and administrated with corresponding drugs by gavage, and the blank group received an equal volume of normal saline. The general condition, body mass, and 24 h autonomic activity of each group were observed. The pathological changes of the liver tissue were observed by hematoxylin-eosin(HE)staining and Masson staining. The expression of gamma-aminobutyric acid (GABA), 5-hydroxytryptamine (5-HT), epinephrine (EPI), norepinephrine (NE), and acetylcholine (ACh) in the liver tissue was detected by enzyme-linked immunosorbent assay. The glutamate (Glu) expression in the liver tissue was detected by the biochemical method. The mRNA levels of biological clock genes Per1, Per2, Cry1, Cry2, Bmal1, and Bmal2 in the liver were determined by Real-time fluorescence quantitative polymerase chain reaction(Real-time PCR). The protein and mRNA levels of factors in the OX1R/PLCβ-1/PKCα/ERK1/2 signaling pathway in the liver were determined by Western blot and Real-time PCR, respectively. ResultCompared with the blank group, the modeling decreased the body mass (P<0.05, P<0.01) and caused mania and disturbed resting rhythms (P<0.01), hepatic muscle fiber fracture, and edema with inflammatory cell infiltration. In addition, the modeling decreased the GABA, 5-HT, EPI, NE, and ACh content, increased Glu content (P<0.01), down-regulated the mRNA levels of Per1, Per2, Cry1, and Cry2 (P<0.01), up-regulated the mRNA levels of Bmal1 and Bmal2 (P<0.01), and promoted the expression of OX1R, PLCβ-1, PKCα, and ERK1/2 at both protein and mRNA levels (P<0.01). Compared with the model group, suvorexant and AMD increased the body mass (P<0.05, P<0.01), alleviated the mania, and increased the resting time and frequency (P<0.05, P<0.01). Moreover, the medications elevated the levels of GABA, 5-HT, EPI, NE, and ACh, lowered the Glu level, up-regulated the mRNA levels of Per1, Per2, Cry1, and Cry2 (P<0.05, P<0.01), down-regulated the mRNA levels of Bmal1 and Bmal2, and inhibited the expression of OX1R, PLCβ-1, PKCα, and ERK1/2 at both mRNA and protein levels (P<0.05, P<0.01). ConclusionAMD can regulate hepatic neurotransmitters and improve circadian rhythm in insomniac rats by inhibiting the OX1R/PLCβ-1/PKCα/ERK1/2 signaling pathway, and high-dose AMD demonstrated the strongest effect.
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ObjectiveTo investigate the effects of Yanghetang (YHT) on breast cancer 4T1 cells and their mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling pathway. MethodThe YHT-containing serum was prepared from SD rats. The rats were randomly assigned into a blank group (normal saline) and low-, medium-, and high-dose (5.8, 11.6, 23.2 g·kg-1, respectively) YHT groups. The serum containing 10% YHT in each group was mixed with 90% RMPI 1640 complete medium, and the mixture was used to interfere with the cells. Cell counting kit-8 (CCK-8) method was used to detect the proliferation of the 4T1 cells treated with YHT for 24, 48, 72 h. The apoptosis, migration, and invasion of 4T1 cells were detected by flow cytometry, scratch test, and Transwell assay, respectively. Western blot was employed to determine the expression levels of MEK1/2, phosphorylation (p)-MEK1/2, ERK1/2, p-ERK1/2, and rat sarcoma virus (RAS) protein. ResultCompared with the blank group, the intervention with YHT-containing serum for 24, 48, and 72 h had significant inhibitory effect on 4T1 cell proliferation (P<0.05, P<0.01). After intervention with YHT-containing serum for 48 h, the apoptosis rate of cells increased (P<0.01). Compared with the blank group, the intervention with YHT for 24 h and 48 h decreased the healing ability of cells in the scratch test (P<0.01). The invasive ability of cells treated with the low, medium, and high-dose YHT containing serum showed a decreasing trend (P<0.01). Compared with the blank group, YHT-containing serum did not change the expression of MEK1/2 and ERK1/2 while down-regulating the expression of p-MEK1/2, p-ERK1/2, and RAS protein (P<0.01). ConclusionYHT can inhibit the proliferation, migration, and invasion and promote the apoptosis of breast cancer 4T1 cells. In may promote the apoptosis by inhibiting the MEK/ERK signaling pathway and down-regulating the expression of p-MEK1/2, p-ERK1/2, and RAS protein.
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With the aging of population, osteoporosis has become one of the main diseases endangering the health of the elderly in China. Therefore, the research on osteoporosis has become a hot spot. Since Chinese medicines demonstrate significant therapeutic effects on osteoporosis, this issue is attracting increasing attention from researchers, especially in the deciphering of the molecular mechanism. This paper introduces the mechanism of the prevention and treatment of osteoporosis by Chinese medicines via the mitogen-activated protein kinase (MAPK) signaling pathway, aiming to provide a theoretical basis for deciphering the mechanism of Chinese medicines in the treatment of osteoporosis and promoting their clinical application. MAPK signaling pathway mainly involves p38 MAPK, extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK), and extracellular signal-regulated kinase 5 (ERK5). Studies have shown that these proteins play a role in the progression of osteoporosis by regulating cell proliferation, differentiation, and apoptosis. Chinese medicines as a unique therapy with Chinese characteristics has definite efficacy, high safety, and mild side effects. Researchers have proved by experiments that the extracts or compounds of Chinese medicines can significantly mitigate osteoporosis by regulating the proteins involved in the MAPK signaling pathway. Therefore, this article reviews the relevant studies with focus on these proteins.
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OBJECTIVE To investigate the anti-pulmonary fibrosis effect of linarin in vivo and in vitro, and investigate its mechanism preliminarily. METHODS C57BL/6J mice were randomly divided into normal group (carboxymethylcellulose sodium), model group (carboxymethylcellulose sodium), positive control group (pirfenidone, 200 mg/kg), linarin low-dose and high-dose groups (12.5, 25 mg/kg), with 8 mice in each group. Except for normal group, pulmonary fibrosis model was induced in other groups. After modeling, they were given relevant medicine intragastrically, once a day, for consecutive 14 d. The general situation of mice was observed, and their lung indexes were measured; the levels of tumor necrosis factor-α (TNF-α) and transforming growth factor-β1( TGF-β1) in serum and interleukin-6 (IL-6) in lung tissue were determined. Hematoxylin-eosin (HE) staining and Masson staining were used to observe the histopathological morphology of lung. The pulmonary fibrosis was scored according to Ashcroft score standard. The expressions of α-smooth muscle actin (α-SMA) and (type Ⅰ collagen, Collagen Ⅰ), phosphorylated extracellular signal-regulated kinase (p-ERK1/2) and TGF-β1 in lung tissues were detected. HFL1 cells were stimulated by TGF- β1 to form pulmonary fibrosis model in vitro, which were divided into normal group, model group and linarin low-, medium- and high-concentration groups (3.7, 7.4, 14.8 mg/L). After being cultured for 48 h, the protein expressions of α-SMA, Collagen Ⅰ and p-ERK1/2 in HFL1 cells were detected. RESULTS In vivo, compared with normal group, the lung index of model group and the levels of TNF- α, TGF- β1 and IL-6 were significantly increased (P<0.01). There were a large number of inflammatory infiltration and cellular fibrosis lesions in the alveoli, and a large number of collagen depositions. The scores of HE staining and Masson staining were significantly increased (P<0.01). The protein expressions of α-SMA, Collagen Ⅰ, p-ERK1/2 and TGF-β1 in lung tissue were up-regulated significantly (P<0.01). Compared with model group, above indexes of mice were improved significantly in linarin high-dose group (P<0.05 or P<0.01), and most of indexes (except for lung index) were improved significantly in linarin low-dose group (P<0.05 or P<0.01). In vitro, compared with blank group, the density of cells in the model group increased, and obvious proliferation and other changes occurred; protein expressions of α-SMA, Collagen Ⅰ and p-ERK1/2 were significantly up-regulated (P<0.05 or P<0.01). Compared with model group, the cell density of each concentration group was decreased and the morphology gradually returned to normal; the expressions of above proteins in linarin high-concentration group and the protein expression of p-ERK1/2 in linarin medium-concentration group were down-regulated significantly(P<0.05 or P<0.01). CONCLUSIONS Linarin may regulate ERK and inflammatory pathways to reduce the inflammatory response, thereby exerting anti-pulmonary fibrosis effect.
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Extracellular signal-regulated kinase 1/2 (ERK1/2) is a serine/threoninekinase involved in the signal transduction cascade of Ras-Raf-mitogen-activated protein kinase (MEK)-ERK.It participates in the cell growth,proliferation and even invasion by regulating gene transcription and expression.The occurrence of a variety of diseases such as lung cancer,liver cancer,ovarian cancer,cervical cancer,endometriosis,and preeclampsia,as well the metastasis and disease progression,is closely associated with the regulation of cell invasion by ERK1/2 signaling pathway.Therefore,exploring the regulation of ERK1/2 signaling on cell invasion and its role in pathogenesis of diseases may help to develop more effective treatment schemes.This article introduces recent progress in the regulation of ERK1/2 signaling on cell invasion and the role of such regulation in diseases,with a view to give new insights into the clinical treatment of ERK 1/2-related diseases.
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Female , Pregnancy , Humans , Mitogen-Activated Protein Kinase 3 , Signal Transduction , Mitogen-Activated Protein Kinases , Cell Cycle , Cell ProliferationABSTRACT
Objective To investigate the effect of XMD17-109 on the viability of glioma cells and its molecular mechanism based on extracellular signal-regulated kinase 5(ERK5)/inositol 1,4,5-trisphosphate receptor-interacting protein(ITPRIP)signaling pathway.Methods U251 glioma cells were routinely cul-tured,and ERK5 activity was inhibited by XMD17-109.ERK5 knockdown and ERK5 overexpression models were constructed by transfection of RNA fragments and plasmids,respectively.Cells were divided divided into the XMD17-109 group,the Control group,the siERK5 group,the siNC group,siERK5-OE group,the Vector group,the ERK5-OE+XMD17-109 group and the Vector+XMD17-109 group.The cell viability was detected by CCK-8,scratch and flow cytometry experiments and so on.The mRNA and protein expression levels of ERK5 and ITPRIP were detected by reverse transcription-quantitative real time PCR(RT-qPCR)and West-ern blot.Results Compared with the Control group,the cell viability of the XMD17-109 group decreased,and the expression level of ITPRIP decreased(P<0.05).Compared with the siNC group,the cell viability of the siERK5 group was decreased,and the expression level of ITPRIP was decreased(P<0.05).Compared with the Vector group,the cell viability of the ERK5-OE group was enhanced,and the expression level of ITPRIP was increased(P<0.05).Compared the with Vector+XMD17-109 group,the cell viability of the ERK5-OE+XMD17-109 group was enhanced,and the expression level of ITPRIP was increased(P<0.05).Conclusion XMD17-109 can inhibit the viability of glioma cells by inhibiting ERK5/ITPRIP signaling pathway,which is expected to be a potential drug for glioma treatment.
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Metformin, the first-line treatment of type 2 diabetes, has been also increasingly used in the treatment of some skin diseases, such as psoriasis. This review summarizes therapeutic mechanisms of and clinical research progress in metformin in the treatment of psoriasis, aiming to provide ideas and methods for the treatment of psoriasis, especially psoriasis complicated by metabolic diseases.
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Objective:To investigate the protective role of extracellular signal-regulated kinase (ERK) signaling pathway in the process that vasonatrin peptide (VNP) reduces hepatic ischemia-reperfusion injury in rats.Methods:Twenty SD rats, weighting 200-250 g, were randomly divided into four groups and each group has five rats. The four groups were sham operation group (S group), ischemia-reperfusion group (I/R group), VNP group (V group) and PD98059+ VNP group (P+ V group). In the rat model of hepatic warm ischemia and reperfusion, the hepatic artery and portal vein of the left lobe and middle lobe of the liver were clamped with arterial clamp for 45 min followed by reperfusion for 120 min. In the V group, VNP (50 μg/kg) was injected 10 minutes before ischemia. In the P+ V group, PD98059 (2 mg/kg) was injected 20 min before VNP injection followed by VNP administration and I/R treatment. The serum levels of alanine amino transaminase (ALT), aspartate amino transferase (AST), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and the superoxide dismutase (SOD) in liver tissue homogenate and malondialdehyde (MDA) were measured. The histopathology of liver tissue was observed. The contents of p-ERK1/2 were detected by Western blot.Results:Compared with S group, in I/R group and P+ V group the serum levels of ALT [(489.65±11.22), (333.05±24.77) vs. (33.78±4.88) U/L], AST [(651.43±14.99), (503.18±21.48) vs. (154.84±12.32) U/L], TNF-α [(12.83±1.09), (9.64±0.57) vs. (2.11±0.11) ng/L], IL-1β [(7.19±0.62), (5.12±0.22) vs. (1.10±0.49) ng/L], MDA [(8.00±0.88), (5.60±1.01) vs. (2.76±1.29) μmol/mg] increased, while SOD [(54.89±10.60), (68.85±8.33) vs. (126.10±15.63) nmol/mg]decreased (all P<0.05). The histopathology of liver tissue revealed that liver structure damaged more seriously in I/R group and P+ V group. Western blot analysis showed that p-ERK1/2 decreased significantly in I/R group and P+ V group. Compared with I/R group, ALT, AST, MDA, TNF-α and IL-1β decreased significantly and SOD increased significantly in V group (all P<0.05). The histopathology of liver tissue revealed that liver structure was damaged slightly, and p-ERK1/2 increased significantly in V group compared with I/R group ( P<0.05). Conclusion:VNP can significantly reduce hepatic ischemia-reperfusion injury through activation of p-ERK1/2 signaling pathway and inhibition of hepatocyte inflammatory response.
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ObjectiveTo investigate the mechanism of Yiqi Huoxue Tongluo prescription (YHTP) in the treatment of diabetic neuropathic pain (DNP). MethodNinety SPF-grade SD male rats were randomized into blank, model, low- (2.25 g·kg-1), medium- (4.5 g·kg-1), and high-dose (9 g·kg-1) YHTP, and mecobalamin (0.175 mg·kg-1) groups. Except those in the blank group, the rats in the remaining 5 groups were fed with a high-fat and high-glucose diet and subjected to intraperitoneal injection of low-dose (35 mg·kg-1) streptozotocin (STZ) to establish the model of DNP. The sciatic nerve conduction velocity in DNP rats was measured by the neurophysiological method, and the levels of interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α (TNF-α) were measured by enzyme-linked immunosorbent assay (ELISA). Real-time fluorescence quantitative polymerase chain reaction (Real-time PCR) was employed to measure the mRNA levels of glial fibrillary acidic protein (GFAP) and extracellular signal-regulated kinase (ERK) in the spinal cord. Western blot was employed to measure the protein levels of GFAP and phosphorylated ERK (p-ERK), and immunofluorescence staining to measure the fluorescence intensity of GFAP and p-ERK in the spinal cord. In the cell experiments, 100 mmol·L-1 high glucose was used to induce the activation of astrocytes (CTX-TNA2) for the modeling of nerve cell injury. The cells were randomized into the normal, model, drug-containing serum (10% YQHT), inhibitor [10 mol·L-1 corynoxeine (COR)], drug-containing serum + inhibitor (10% YHTP + 10 mol·L-1 COR) groups. The levels of pro-inflammatory factors (TNF-α and IL-1β) and the anti-inflammatory factor IL-10 in CTX-TNA2 cells were determined by ELISA, and the protein levels of GFAP and p-ERK in CTX-TNA2 cells by Western blot. ResultThe animal experiments showed that compared with the blank group, the model group presented reduced mechanical withdrawal threshold (MWT), thermal work limit (TWL), and nerve conduction velocity, elevated levels of fasting blood glucose, IL-1β, TNF-α, and IL-6, and up-regulated protein levels of GFAP and p-ERK, and mRNA levels of ERK1, ERK2, GFAP (P<0.01). Compared with model group, YHTP increased the MWT, TWL, and sciatic nerve conduction velocity (P<0.01), lowered the levels of IL-1β, TNF-α, and IL-6 (P<0.01), and down-regulated the protein levels of GFAP and p-ERK, and mRNA levels of ERK1, ERK2, GFAP in the spinal cord (P<0.05, P<0.01). The cell experiments showed that compared with the blank group, the model group had decreased survival rate, elevated levels of pro-inflammatory factors, and up-regulated protein levels of ERK and GFAP (P<0.01). Compared with the model group, the YHTP-containing serum lowered the levels of IL-1β and TNF-α (P<0.05, P<0.01), elevated the level of IL-10 (P<0.01), and down-regulated the protein levels of ERK and GFAP (P<0.01). ConclusionYHTP may inhibit the activation of astrocytes by inhibiting the ERK signaling pathway to reduce inflammation and thus relieve DNP.
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The mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway is widely activated by a variety of extracellular stimuli, and its dysregulation is associated with the proliferation, invasion, and migration of cancer cells. ERK1/2 is located at the distal end of this pathway and rarely undergoes mutations, making it an attractive target for anticancer drug development. Currently, an increasing number of ERK1/2 inhibitors have been designed and synthesized for antitumor therapy, among which representative compounds have entered clinical trials. When ERK1/2 signal transduction is eliminated, ERK5 may provide a bypass route to rescue proliferation, and weaken the potency of ERK1/2 inhibitors. Therefore, drug research targeting ERK5 or based on the compensatory mechanism of ERK5 for ERK1/2 opens up a new way for oncotherapy. This review provides an overview of the physiological and biological functions of ERKs, focuses on the structure-activity relationships of small molecule inhibitors targeting ERKs, with a view to providing guidance for future drug design and optimization, and discusses the potential therapeutic strategies to overcome drug resistance.
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OBJECTIVE@#To investigate the influence of chronic masseter hyperalgesia induced by 17β-estradiol (E2) and experimental occlusal interference (EOI) on underlying mechanism in hippocampus of ovariectomized (OVX) rats.@*METHODS@#In the study, 32 OVX rats were randomly divided into 4 groups (8 rats/group): The control group was OVX group, and 0 μg/d E2 (vehicle) injection was started 7 d after OVX without EOI; in the experimental group (1) OVX + E2 group, 80 μg/d E2 injection was started 7 d after OVX without EOI; in the experimental group (2) OVX + EOI group, vehicle injection was started 7 d after OVX and EOI was applied 17 d after OVX; in the experimental group (3) OVX + E2 + EOI group, 80 μg/d E2 injection was started 7 d after OVX and EOI was applied 17 d after OVX. Bilateral masseter muscle mechanical withdrawal thresholds were measured before OVX, 7 days after OVX (before E2 injection), 17 days after OVX (10 days after E2 injection and before EOI) and 24 days after OVX (7 days after EOI). Immunofluorescence staining was used to reveal phospho-extracellular signal regulated kinase 1/2 (p-ERK1/2)-positive neurons in CA3 of hippocampus. The protein expression of p-ERK1/2 in hippocampus was detected using Western Blot.@*RESULTS@#Compared with the control group [left side: (135.3±8.5) g, right side: (135.4±10.8) g], bilateral masseter muscle mechanical withdrawal thresholds of OVX+E2 group [left side: (113.3±5.6) g, right side: (112.5 ± 5.6) g] and OVX+EOI group [left side: (93.3±5.4) g, right side: 90.8±5.5) g] were decreased (P < 0.01). Bilateral masseter muscle mechanical withdrawal thresholds were significantly lower in OVX+E2+EOI group [left side: (81.2±6.2) g, right side: 79.8±7.7) g] than in the control, OVX+E2 and OVX+EOI groups (P < 0.05). The proportion of p-ERK1/2 positive neurons in the CA3 region of the hippocampus was increased in the control, OVX+E2, OVX+EOI and OVX+E2+EOI groups in turn, and the difference between the groups was statistically significant (P < 0.05). p-ERK1/2 protein expression was increased in the control, OVX+E2 and OVX+EOI groups in turn, but the difference was not statistically significant (P>0.05). p-ERK1/2 expression was significantly higher in OVX+E2+EOI group than in the other three groups (P < 0.05).@*CONCLUSION@#High concentration of E2 could exacerbated EOI-induced chronic masseter hyperalgesia in ovariectomized rats, and its central mechanism may be related to the upregulation of the phosphorylation of ERK1/2 in hippocampus.
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Animals , Female , Humans , Rats , Estradiol , Hippocampus , Hyperalgesia/chemically induced , Masseter Muscle , Ovariectomy , Rats, Sprague-DawleyABSTRACT
Objective:To clarify the neuroprotective effects of neural cell adhesion molecule (NCAM) derived peptide P2 on in vitro cultured neuron and ischemic stroke rat. Methods:Primary cortical neurons were extracted and cultured, and CCK-8 method was used to observe the protective effect of different concentrations of P2 on cortical neurons under oxygen-glucose deprivation (OGD) conditions.The levels of apoptosis-related proteins and extracellular signal regulated kinase 1/2 (Erk1/2) were observed by Western blot. Clean grade male SD rats were selected for animal experiments. The middle cerebral artery occlusion (MCAO) method was used to establish the rat model of cerebral ischemia/reperfusion injury. The rats with successful model were divided into sham operation group, MCAO group and MCAO+ P2 group according to the random number table, with 12 rats in each group. After operation, rats in MCAO+ P2 group were subcutaneously injected with 1 mg/kg P2 once a day until 14 days after operation, and rats in the other two groups were subcutaneously injected with 0.9% sodium chloride solution of the same volume.Beam-walking test was used to evaluate the motor function of rats.Immunofluorescence staining and Western blot were used to detect the in-situ apoptosis of neuronal cells and the expression of Erk1/2 in ischemic penumbra of rat brains, respectively. All statistical analyses were performed using SPSS 22.0.Repeated measurement ANOVA was used to evaluate the beam-walking experimental data, and one-way ANOVA were used to analyze other experimental data among multiple groups.Results:Compared with OGD group, 0.5, 1.0 and 2.0 μmol/L P2 improved the activity of neurons under OGD conditions, of which 1 μmol/L P2 had the best effect ((2.436±0.284), (1.551±0.410), P<0.05). Western blot showed that the protein levels of bax ((76.120±3.232)%, (88.965±5.208)%, P<0.05), cleaved caspase-3 ((76.736±4.306)%, (97.781±8.111)%, P<0.05) and cleaved caspase-9 ((88.833±6.581)%, (104.962±4.788)%, P<0.05) in 1 μmol/L P2 treated group were all lower than those in OGD group, while the protein levels of bcl-2 ((56.146±3.882)%, (43.170±6.945)%, P<0.05) and phosphorylated Erk1/2 ((73.583±8.557)%, (55. 219±4.615)%, P<0.05) in 1 μmol/L P2 treated group were both higher than those in OGD group. Compared with MCAO group, on the 14th day after P2 intervention, the slip ratio of hindlimb of the paralyzed hind limbs of rats was lower ((23.438±11.540)%, (41.733±13.631)%, P<0.05), the apoptosis rate of neurons around the focus was lower ((13.144±6.485)%, (26. 699±6. 402)%, P<0.05), and the level of phosphorylated Erk1/2 protein in the brain tissues around the infarct focus was higher ((74.062±7.458)%, (53.327±7.093)%, P<0.05). Conclusion:Low doses of neural cell adhesion molecule derived peptide P2 exert neuroprotective effects on OGD neurons and ischemic stroke rats. The underlying mechanism may be related to the activation of Erk.
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Objective:To investigate changes in circadian gene cryptochrome 2 (CRY2) expression in mouse models of psoriasis and HaCaT cells, and to explore underlying mechanisms.Methods:Imiquimod-induced mouse model experiment: 12 C57BL/6 female mice were randomly and equally divided into imiquimod group receiving topical imiquimod treatment for 5 consecutive days and control group receiving no treatment; these mice were sacrificed on day 6, skin tissues were resected from the back of mice, and immunofluorescence staining was performed to determine the CRY2 expression in the epidermis. HaCaT cell transfection experiment: HaCaT cells with small interfering RNA (siRNA) -mediated knockdown of CRY2 served as siRNA-CRY2 group, and siRNA-NC group as control group; 5-ethynyl-2′-deoxyuridine (EdU) staining was performed to evaluate the proliferative activity of the HaCaT cells, real-time fluorescence-based quantitative PCR (qPCR) to determine the mRNA expression of chemokines in the HaCaT cells, and Western blot analysis to determine phosphorylation levels of extracellular signal-regulated kinase 1/2 (ERK1/2) . Tumor necrosis factor-α (TNF-α) -stimulated animal and cell experiments: 12 C57BL/6 female mice were randomly and equally divided into TNF-α group subcutaneously injected with TNF-α solution in the ear for 6 days, and phosphate buffered saline (PBS) group subcutaneously injected with the same amount of PBS; the mice were sacrificed on day 7, skin tissues were resected from the ear of mice, and immunofluorescence staining was conducted to determine the CRY2 expression in the epidermis; CRY2-knockdown HaCaT cells stimulated with 50 ng/ml TNF-α for 12 hours served as siRNA-CRY2 + TNF-α group, and siRNA-NC + TNF-α group as control group; qPCR was performed to determine the mRNA expression of chemokines in HaCaT cells in the above groups. Statistical analysis was carried out by using two-independent-sample t test. Results:Immunofluorescence staining showed that the CRY2 protein expression was significantly lower in the mouse dorsal epidermis in the imiquimod group (0.94 ± 0.23) than in the control group (2.30 ± 0.25, t = 3.99, P = 0.016) . Compared with the siRNA-NC group, the siRNA-CRY2 group showed significantly increased proportions of EdU-positive cells (48.13% ± 10.97% vs. 38.23% ± 0.81%, t = 5.00, P = 0.007) , mRNA expression levels of chemokines CXCL1 and CXCL8, as well as significantly increased phosphorylated (p) -ERK1/2 protein expression levels (all P < 0.05) , while there were no significant differences in the CCL20 mRNA expression or ERK1/2 protein expression between the two groups (both P > 0.05) . Immunofluorescence staining showed significantly decreased CRY2 protein expression level in the mouse ear epidermis in the TNF-α group (0.37 ± 0.34) compared with the PBS group (2.04 ± 0.17, t = 4.38, P = 0.012) ; the relative mRNA expression levels of chemokines CXCL1, CXCL8, and CCL20 in HaCaT cells were significantly higher in the siRNA-CRY2 + TNF-α group than in the siRNA-NC + TNF-α group (all P < 0.05) . Conclusion:CRY2 was markedly underexpressed in psoriasis, which might promote the proliferation of keratinocytes and expression of chemokines CXCL1, CXCL8 and CCL20, and TNF-α might be an upstream cytokine that could downregulate CRY2 expression.
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ObjectiveTo preliminarily explore the mechanism of Shufeng Tongluo prescription (SFTLP) in inhibiting airway inflammation in asthma mice by affecting the expression levels of eotaxin in the serum, CC type chemokine receptor 3 (CCR3), and extracellular signal-regulated kinase (ERK) phosphorylation in lung tissues. MethodSeventy C57BL/6 mice were randomly divided into a blank group, a model group, low-, medium-, and high-dose SFTLP groups (7.75, 15.5, 30 g·kg-1), a pertussis toxin (PTX) group, a CCR3 inhibitor (SB328437) group, a phosphoinositide 3-kinase (PI3K) inhibitor (LY294002) group, a p38 protein kinase antagonist inhibitor (SB203580) group, and an ERK inhibitor (PD98059) group. The asthma model was induced in mice by intraperitoneal injection of ovalbumin (OVA) and aluminum hydroxide [Al(OH)3] combined with OVA atomization (0.2 mL for all). After modeling, hematoxylin-eosin staining (HE staining) was used to observe the inflammatory infiltration of lung tissues in mice. Enzyme-linked immunosorbent assay (ELISA) was used to detect the serum levels of eotaxin [CC chemokine ligand (CCL) 11 and CCL24) in each group. Western blot was used to detect the levels of ERK phosphorylation and CCR3 in lung tissues. ResultCompared with the blank group, the model group showed obvious bronchial constriction, lumen stenosis, damaged alveolar structure, massive inflammatory cell infiltration in lung tissues, mucous plug in the bronchus, edema in the submucosal tissues of the trachea, increased folds, increased serum levels of CCL11 and CCL24 (P<0.01), and increased expression of CCR3 protein in lung tissues (P<0.05). The ERK levels in lung tissues of the model group and the PTX group increased (P<0.05). The level of p-ERK in lung tissues of the model group and the low-dose SFTLP group increased (P<0.05). As revealed by pathological results, compared with the model group, the high-dose SFTLP group showed relieved lung lesions. The high-dose SFTLP group and the SB328437 group showed reduced CCL11 content (P<0.05). The low- and high-dose SFTLP group, the PTX group, the SB203580 group, the PD98059 group, and the SB328437 group showed decreased CCR3 protein expression in lung tissues (P<0.05). The high-dose SFTLP group and the PD98059 group showed reduced p-ERK level (P<0.05). The PD98059 group showed reduced ERK level (P<0.05). ConclusionSFTLP can inhibit airway inflammation in asthma, and the mechanism may be related to the inhibition of eosinophil activation by down-regulating CCR3 and CCL11 expression and ERK phosphorylation.
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Objective:To explore the effect of extracellular signal-regulated kinase (ERK) inhibitor PD98059 on calpain-related proteins in the brain, and to understand the pathophysiological changes of calpain in cerebral ischemia/reperfusion injury (CIRI).Methods:Forty-two rats were divided into sham operation (Sham) group ( n = 6), model group ( n = 12), dimethyl sulfoxide (DMSO) control group ( n = 12), and PD98059 group ( n = 12) by random number table. The rat model of CIRI induced by cardiac arrest-cardiopulmonary resuscitation (CA-CPR) was reproduced by transesophageal electrical stimulation to induce ventricular fibrillation. In the Sham group, only the basic operations such as anesthesia, tracheal intubation, and arteriovenous catheterization were performed without CA-CPR. The rats in the DMSO control group and PD98059 group were injected with DMSO or PD98059 0.30 mg/kg via femoral vein, respectively, 30 minutes after the restoration of spontaneous circulation (ROSC), and rats in the Sham group and model group were given the same amount of normal saline. The duration of CPR, 24-hour survival rate and neurological deficit score (NDS) after ROSC were recorded. Hematoxylin-eosin (HE) staining and Nissl staining were used to observe the pathological changes of the cerebral cortex. The expressions of phosphorylated ERK (p-ERK), ERK, calpastatin, calpain-1, and calpain-2 were detected by Western blotting. The co-expression of p-ERK and calpain-2 was detected by double immunofluorescence. Results:There were no significant differences in the duration of CPR and 24-hour survival rate among all groups. In the model group, the nuclei of the cerebral cortex were obviously deformed and pyknotic, cells vacuoles and tissues were arranged disorderly, Nissl corpuscles were significantly reduced, NDS scores were also significantly reduced, level of ERK phosphorylation was increased, and calpain-2 protein was significantly up-regulated compared with the Sham group. There was no significant difference in the above parameters between the DMSO control group and the model group. After intervention with PD98059, the pathological injury of brain tissue was significantly improved, Nissl corpuscles were significantly increased, the NDS score was significantly higher than that in the model group [75.0 (72.0, 78.0) vs. 70.0 (65.0, 72.0), P < 0.05], the level of ERK phosphorylation and calpain-2 protein expression were significantly lower than those in the model group [p-ERK (p-ERK/ERK): 0.65±0.12 vs. 0.92±0.05, calpain-2 protein (calpain-2/GAPDH): 0.73±0.10 vs. 1.07±0.14, both P < 0.05], while there was no significant difference in the expressions of calpastatin and calpain-1 in the cerebral cortex among all the groups. Double immunofluorescence staining showed that p-ERK and calpain-2 were co-expressed in cytosol and nucleus, and the co-expression rate of p-ERK and calpain-2 in the model group was significantly higher than that in the Sham group [(38.6±4.3)% vs. (9.2±3.5)%, P < 0.05], while it was significantly lowered in the PD98059 group compared with the model group [(18.2±7.0)% vs. (38.6±4.3)%, P < 0.05]. Conclusions:ERK together with calpain-2 participated in CIRI induced by CA-CPR. PD98059 inhibited the expression of calpain-2 and ERK phosphorylation. Therefore, ERK/calpain-2 may be a novel therapeutic target for CIRI.