Suppression of PTRF Alleviates Post-Infectious Irritable Bowel Syndrome via Downregulation of the TLR4 Pathway in Rats.

Background: Accumulating evidence suggests that the polymerase I and transcript release factor (PTRF), a key component of the caveolae structure on the plasma membrane, plays a pivotal role in suppressing the progression of colorectal cancers. However, the role of PTRF in the development of functional gastrointestinal (GI) disorders remains unclear. Post-infectious irritable bowel syndrome (PI-IBS) is a common functional GI disorder that occurs after an acute GI infection. Here, we focused on the role of PTRF in the occurrence of PI-IBS and investigated the underlying mechanisms. Methods: Lipopolysaccharide (LPS) (5 µg/ml) was used to induce inflammatory injury in human primary colonic epithelial cells (HCoEpiCs). Furthermore, a rat model of PI-IBS was used to study the role of PTRF. Intestinal sensitivity was assessed based on the fecal water content. A two-bottle sucrose intake test was used to evaluate behavioral changes. Furthermore, shRNA-mediated knockdown of PTRF was performed both in vitro and in vivo. We detected the expression of PTRF in colonic mucosal tissues through immunohistochemistry (IHC), western blotting (WB), and immunofluorescence (IF) analysis. Luciferase activity was quantified using a luciferase assay. Co-localization of PTRF and Toll-like receptor 4 (TLR4) was detected using IF analysis. The activation of the signaling pathways downstream of TLR4, including the iNOs, p38, extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK) pathways, was detected via WB. The levels of NO, IL-1ß, IL-6, and TNF-α were measured using enzyme-linked immunosorbent assays. Results: LPS significantly induced PTRF expression and signaling downstream of TLR4, including p38, ERK, and JNK pathways, in HCoEpiCs. Moreover, shRNA-mediated knockdown of PTRF in HCoEpiCs significantly decreased the phosphorylation of JNK, ERK, and p38 and iNOS expression. In PI-IBS rats, the lack of PTRF not only reduced fecal water content and suppressed depressive behavior but also increased the body weight. Furthermore, we found a strong co-localization pattern for PTRF and TLR4. Consistently, the lack of PTRF impaired TLR4 signaling, as shown by the decreased levels of p-JNK, p-ERK, and p-p38, which are upstream factors involved in iNOS expression. Conclusion: PTRF promoted PI-IBS and stimulated TLR4 signaling both in vitro and in vivo. The results of this study not only enlighten the pathogenesis of PI-IBS but also help us understand the biological activity of PTRF and provide an important basis for the clinical treatment of PI-IBS by targeting PTRF.

Ginsenoside Rd promotes neurogenesis in rat brain after transient focal cerebral ischemia via activation of PI3K/Akt pathway.

AIM: To investigate the effects of ginsenoside Rd (Rd) on neurogenesis in rat brain after ischemia/reperfusion injury (IRI). METHODS: Male SD rats were subjected to transient middle cerebral artery occlusion (MCAO) followed by reperfusion. The rats were injected with Rd (1, 2.5, and 5 mg·kg(-1)·d(-1), ip) from d 1 to d 3 after MCAO, and with BrdU (50 mg·kg(-1)·d(-1), ip) from d 3 to d 6, then sacrificed on 7 d. The infarct size and neurological scores were assessed. Neurogenesis in the brains was detected by BrdU, DCX, Nestin, and GFAP immunohistochemistry staining. PC12 cells subjected to OGD/reperfusion were used as an in vitro model of brain ischemia. VEGF and BDNF levels were assessed with ELISA, and Akt and ERK phosphorylation was measured using Western blotting. RESULTS: Rd administration dose-dependently decreased the infarct size and neurological scores in the rats with IRI. The high dose of Rd 5 (mg·kg(-1)·d(-1)) significantly increased Akt phosphorylation in ipsilateral hemisphere, and markedly increased the number of BrdU/DCX and Nestin/GFAP double-positive cells in ischemic area, which was partially blocked by co-administration of the PI3 kinase inhibitor LY294002. Treatment with Rd (25, 50, and 100 µmol/L) during reperfusion significantly increased the expression of VEGF and BDNF in PC12 cells with IRI. Furthermore, treatment with Rd dose-dependently increased the phosphorylation of Akt and ERK, and significantly decreased PC12 cell apoptosis, which were blocked by co-application of LY294002. CONCLUSION: Rd not only attenuates ischemia/reperfusion injury in rat brain, but also promotes neurogenesis via increasing VEGF and BDNF expression and activating the PI3K/Akt and ERK1/2 pathways.

Protective effect of kaempferol on LPS plus ATP-induced inflammatory response in cardiac fibroblasts.

Inflammatory response is an important mechanism in the pathogenesis of cardiovascular diseases. Cardiac fibroblasts play a crucial role in cardiac inflammation and might become a potential therapeutic target in cardiovascular diseases. Kaempferol, a flavonoid commonly existing in many edible fruits, vegetables, and Chinese herbs, is well known to possess anti-inflammatory property and thus has a therapeutic potential for the treatment of inflammatory diseases. To date, the effect of kaempferol on cardiac fibroblasts inflammation is unknown. In this study, we investigated the anti-inflammatory effect of kaempferol on lipopolysaccharide (LPS) plus ATP-induced cardiac fibroblasts and explored the underlying mechanisms. Our results showed that kaempferol at concentrations of 12.5 and 25 µg/mL significantly suppressed the release of TNF-α, IL-1ß, IL-6, and IL-18 and inhibited activation of NF-κB and Akt in LPS plus ATP-induced cardiac fibroblasts. These findings suggest that kaempferol attenuates cardiac fibroblast inflammation through suppression of activation of NF-κB and Akt.

[Protective effect of rosmarinic acid on hypoxia/reoxygenation injury in cardiomyocytes].

OBJECTIVE: To study the protective effect of rosmarinic acid (Ros A) on the primary cardiomyocyte hypoxia/reoxygenation (H/R) injury. METHOD: Primary cardiomyocytes of rats were cultured in vitro to establish the H/R injury of cardiomyocytes and observe the changes in the cell viability and LDH leakage. The changes in ATP content and ROS in cardiomyocytes were measured by using chemiluminescence and fluorescent probe technique. The effects of rosmarinic acid on the apoptosis of cardiomyocytes, cleaved-caspase 3, Akt and p-Akt protein expression were further detected by flow cytometry and western blot analysis. RESULT: According to the experimental results, Ros A at doses of 25, 50, 100 mg x L(-1) could inhibit the decrease in H/R-induced cell viability, LDH leakage and excessive ROS generation, and maintain the ATP level in cells. Ros A at doses of 50, 100 mg x L(-1) could remarkably inhibit the H/R-induced cardiomyocyte apoptosis and down-regulate the expression of cleaved caspase-3. Moreover, Ros A at doses of 100 mg x L(-1) could significantly up-regulate the expression of p-Akt. CONCLUSION: Ros A has the significant effect in resisting the cardiomyocyte H/R injury, improve cardiomyocyte energy metabolism and reduce cell apoptosis, which is related to the activation of Akt pathway.

[Study on effect of huatuo zaizao extractum on focal cerebral ischemia/reperfusion neurogenesis in rats and its mechanisms].

OBJECTIVE: To observe the effect of Huatuo Zaizao extractum (HTZZ) on focal cerebral ischemia/reperfusion (I/R) neurogenesis in rats induced by middle cerebral artery occlusion (MCAO) and its mechanism. METHOD: Totally 55 healthy adult male Sprague-Dawley rats were divided into the sham operation group, the MCAO model group and HTZZ high, middle and low dose groups (5, 2.5, 1.25 g x kg(-1)), with 11 rats in each group, and orally administered with drugs. The focal cerebral ischemia model was established by performing a middle cerebral artery occlusion (MCAO, 90 min) followed by a seven-day reperfusion (once a day). The neurogenesis and expressions of extracellular signal-regulated kinase (ERK) and cAMP response element binding protein (CREB) were detected by the immunofluorescent staining. The enzyme linked immunosorbent assay (ELISA) was adopted to determine the vascular endothelial growth factor (VEGF) and brain-derived neurotrophic factor (BDNF). RESULT: MCAO (90 min) followed by a seven-day reperfusion resulted in the significant increase in the number of penumbra cortex newborn neurons (BrdU(+) -NeuN(+)), which was accompanied by the growth of ERK and CREB phosphorylation and VEGF and BDNF levels. HTZZ could promote the generation of newborn neurons (BrdU(+)-NeuN(+)) and the ERK and CREB phosphorylation and increase VEGF and BDNF levels at the ischemic side. CONCLUSION: HTZZ could promote the neurogenesis, which may be the interventional targets of effective traditional Chinese medicine Huatuo Zaizao extractum in promoting the self-repair function of the cerebral ischemic areas.

[Intervention effect of quercetin on inflammatory secretion of cardiac fibroblasts].

To establish neonatal rat cardiac fibroblast inflammatory secretion model by using LPS 100 microg x L(-1) combined with ATP 5 mmol x L(-1), in order to study the inhibitory effect of quercetin on the secretion of inflammatory factors TNF-alpha, IL-1beta and IL-6 of cardiac fibroblasts, further investigate the effect of quercetin on the protein expression of p-NF-kappaB p65 (S276) and p-Akt (S473) by western blot, and discuss the inhibitory effect of quercetin on the inflammatory secretion of cardiac fibroblasts. According to the findings, quercetin with the concentrations between 51.74 micromol x L(-1) and 827.81 micromol x L(-1) had no significant effect on the activity of cardiac fibroblasts. Quercetin with the concentrations of 82.78, 41.39, 20.70 micromol x L(-1) could notably inhibit the increase of TNF-alpha and IL-1beta induced by LPS 100 microg x L(-1) for 3 h and then ATP 5 mmol x L(-1) for 36 h (P < 0.01 or P < 0.05). Quercetin with the concentrations of 82.78, 41.39 micromol x L(-1) could notably inhibit the increase of IL-6 induced LPS 100 microg x L(-1) for 3 h and then ATP 5 mmol x L(-1) for 36 h (P < 0.05), without any notable effect of quercetin with the concentration of 20.70 micromol x L(-1). Quercetin with the concentrations of 82.78, 41.39, 20. 70 micromol x L(-1) could notably inhibit the NF-kappaB p65 (S276) activation induced by LPS 100 microg x L(-1) for 3 h and then ATP 5 mmol x L(-1) for 15 min, with the most significant effect in 20.70 micromol x L(-1). Quercetin with the concentrations of 82.78, 41.39, 20.70 micromol x L(-1) could notably inhibit the increase of p-Akt(473) expression induced by LPS 100 microg x L(-1) for 3 h and then ATP 5 mmol x L(-1) for 240 min (P < 0.05). Therefore, this study believes that quercetin could attenuate the secretion of inflammatory factors TNF-alpha, IL-1beta and IL-6 of cardiac fibroblasts by inhibiting the activation of NF-kappaB p65 (S276) and Akt (473).

Cardioprotective effect of protocatechuic acid on myocardial ischemia/reperfusion injury.

Protocatechuic acid (PCA), a phenolic compound and one of the main metabolites of complex polyphenols, has been found to possess various biological activities, and it may have a potential in the treatment of ischemic heart diseases. This study explored the cardioprotective effect of PCA on myocardial ischemia/reperfusion (MI/R) injury and the underlying mechanisms. In an in vivo rat model of MI/R injury, myocardial infarct size, serum TNF-a level, and platelet aggregation were measured. In a primary neonatal rat cardiomyocyte model of hypoxia/ reoxygenation (H/R) injury, the apoptotic rate, expressions of cleaved caspase-3, and phosphorylated Akt were observed. We found that PCA significantly reduced myocardial infarct size, serum TNF-a level, and platelet aggregation. In vitro experiments revealed that PCA significantly inhibited the apoptotic rate and the expression of cleaved caspase-3, and it upregulated the expression of phosphorylated Akt in cardiomyocytes subjected to H/R injury. Our results suggest that PCA can provide a significant protection against MI/R injury, which may be at least partially attributed to its inhibitions against injury induced by MI/R including the inflammatory response, platelet aggregation, and cardiomyocytes apoptosis.

Total glucosides of paeony inhibit the proliferation of fibroblast-like synoviocytes through the regulation of G proteins in rats with collagen-induced arthritis.

The aim of this study was to investigate the expression of G proteins in fibroblast-like synoviocytes (FLSs) from rats with collagen-induced arthritis (CIA) and to determine the effect of total glucosides of paeony (TGP). CIA rats were induced with chicken type II collagen (CCII) in Freund's complete adjuvant. The rats with experimental arthritis were randomly separated into five groups and then treated with TGP (25, 50, and 100mg/kg) from days 14 to 35 after immunization. The secondary inflammatory reactions were evaluated through the polyarthritis index and histopathological changes. The level of cyclic adenosine monophosphate (cAMP) was measured by radioimmunoassay. The FLS proliferation response was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The toxin-catalyzed ADP-ribosylation of G proteins was performed through autoradiography. The results show that TGP (25, 50, and 100mg/kg) significantly decreased the arthritis scores of CIA rats and improved the histopathological changes. TGP inhibited the proliferation of FLSs and increased the level of cAMP. Moreover, the FLS proliferation and the level of Gαi expression were significantly increased, but the level of Gαs expression was decreased after stimulation with IL-1ß (10ng/ml) in vitro. TGP (12.5 and 62.5µg/ml) significantly inhibited the FLS proliferation and regulated the balance between Gαi and Gαs. These results demonstrate that TGP may exert its anti-inflammatory effects through the suppression of FLS proliferation, which may be associated with its ability to regulate the balance of G proteins. Thus, TGP may have potential as a therapeutic agent for the treatment of rheumatoid arthritis.

[Protective effect of succinic acid on primary cardiomyocyte hypoxia/reoxygenation injury].

To establish cardiomyocyte hypoxia/reoxygenation injury model by culturing primary cardiomyocytes from suckling SD rats, in order to study the effect of succinic acid on LDH leakage rate cardiomyocyte ischemia/reperfusion injury. Furthermore, flow cytometry and western blot were conducted to detect the effect of succinic acid on cardiomyocyte apoptosis, cleaved caspase-3 and p-Akt, and discuss the protective effect of succinic acid on primary cardiomyocyte hypoxia/reoxygenation injury of primary cardiomyocytes from neonatal SD rats. According to the findings of the study, succinic acid at the concentrations ranging between 31.25 mg x L(-1) and 500 mg x L(-1) had no significant effect on primary cardiomyocyte activity, and succinic acid at the concentrations of 400, 200, 100, 50 mg x L(-1) could notably reduce cardiomyocyte ischemia/reperfusion LDH leakage rate (P < 0.01 or P < 0.05, respectively). Succinic acid at the concentrations of 400 mg x L(-1) and 200 mg x L(-1) could significantly reduce the percentage of cardiomyocyte apoptosis (P < 0.05), and inhibit the protein expression of cleaved caspase-3 caused by cardiomyocyte ischemia/reperfusion (P < 0.05). Succinic acid at the concentration of 400 mg x L(-1) could remarkably increase the protein expression of cardiomyocyte Akt (P < 0.05), while succinic acid at the concentration of 200 mg x L(-1) had no obvious effect on the protein expression of cardiomyocyte Akt. Therefore, this study demonstrated that succinic acid could inhibit necrosis and apoptosis caused by cardiomyocyte hypoxia/reoxygenation by activating Akt phosphorylation.

Hawthorn leaves flavonoids decreases inflammation related to acute myocardial ischemia/reperfusion in anesthetized dogs.

OBJECTIVE: To investigate the effects and mechanisms of hawthorn leaves flavonoids (HLF) on acute myocardial ischemia/reperfusion in anesthetized dogs. METHODS: The acute ischemia models were prepared by ligating left anterior descending (LAD) artery for 60 min. Qualified 15 male dogs were randomly divided into 3 groups with 5 in each group: blank control (treated with normal saline 3 mL/kg) group, HLF low dosage (5 mg/kg) group and high dosage (10 mg/kg) group, with an once injection through a femoral vein 5 min before reperfusion. Epicardial electrocardiogram was adopted to measure the scope and degree of myocardial ischemia. Simultaneously, neutrophil infiltration in infarct (Inf) and remote site (RS) of myocardial tissue was measured by myeloperoxidase (MPO) activity assay. The serum interleukin-1 (IL-1) and tumor necrosis factorα (TNF-α) content were quantified by radioimmuno-assay. Furthermore, expression of G protein-coupled receptor kinase 2 (GRK2) and nuclear factor κB (NF-κB) in Inf and RS tissue were detected by Western blotting technique. RESULTS: Ischemia and reperfusion increased the MPO activity and IL-1 and TNF-α content. HLF (10 and 5 mg/kg) could significantly decrease the degree and scope of myocardial ischemia; markedly inhibit the increase of MPO activity, and IL-1 and TNF-α content induced by myocardial ischemia/infarction. Furthermore, HLF increased GRK2 expression and inhibited NF-κB expression in Inf tissue. CONCLUSION: HLF could improve the situation of acute myocardial ischemia and inhibit the inflammation in anesthetized dogs, which might be due to its increasing effect on the GRK2 and NF-κB expressions.

[Effect and mechanism of action of total glucosides of paeony on synoviocytes from rats with collagen-induced arthritis].

AIM: To study the effect and mechanism of action of total glucosides of paeony (TGP) on synoviocytes from rats with collagen-induced arthritis (CIA). METHODS: Chicken type II collagen was used to induce CIA in rats. Synoviocytes were separated by incubation with collagenase and trypsin, and its ultrastructural changes were observed under transmission electron microscope. Synoviocyte proliferation was determined by 3-(4,5-dimethylthiazal-2yl) 2,5- diphenyltetrazoliumbromide (MTT) assay, and IL-1 activity in synoviocytes supernatant was measured by thymocyte proliferation assay. TNFa and PGE, produced by synoviocytes were determined by radioimmunoassay. RESULTS: TGP was shown to protect CIA rats against the ultrastructural damages of synoviocytes. Meanwhile, TGP also suppressed the excessive synoviocyte proliferation and over-production of IL-1, TNFalpha and PGE2. CONCLUSION: TGP has inhibitory effect on hyperfunctional synoviocytes of CIA rats and its mechanism of action may be related with the inhibition of abnormal proliferation and secretion of synoviocytes.

Interleukin-1 receptor antagonist intervenes in signaling between different types of synoviocytes in rats with adjuvant arthritis.

AIM: To investigate the mechanisms of interleukin-1 receptor antagonist (IL-1ra) in the treatment of adjuvant arthritis (AA). METHODS: AA was induced in rats by treatment with Freunds complete adjuvant (FCA). Rats were given an intracutaneous injection of IL-1ra (2.5, 10, 40 mg/kg, 3 times per day) from d 14 to d 21 after immunization. Synoviocyte proliferation and the activity of IL-1 were determined by using MTT assay. Tumor necrosis factor alpha (TNF-alpha) and prostaglandin E(2) (PGE(2)) concentrations were measured by radioimmunoassay. The ultrastructure of synoviocytes was observed by using a transmission electron microscope. Phosphorylation of c-Jun N-terminal kinase (JNK), extracellular regulating kinase (ERK) and p38 kinase were detected by Western blot analysis. RESULTS: IL-1ra (10 and 40 mg/kg, ic, d 14-21) modulated the secondary inflammatory reaction (P < 0.01), ultrastructure of synoviocytes and mitogen-activated protein kinase (MAPK) phosphorylation in AA rats. The administration of IL-1ra (10 and 40 mg/kg, ic, d 14-21) in AA rats significantly decreased the production of IL-1, PGE2 and TNF-alpha by macrophage-like synoviocytes (MLS) (P < 0.01). IL-1ra (2.5 mg/kg) also decreased the production of PGE2 (P < 0.01) and TNF-alpha (P < 0.05) by MLS in AA rats. The increased phosphorylation of MAPK and cell proliferation in fibroblast-like synoviocytes (FLS) stimulated by supernatants of MLS in AA rats was also inhibited by IL-1ra (10 and 40 mg/kg, ic, d 14-21). CONCLUSION: IL-1ra has anti-inflammatory effects because it modulates the ultrastructure of synoviocytes, decreases the production of pro-inflammatory mediators by MLS, and inhibits the phosphorylation of MAPK in FLS.

Total glucosides of paeony suppresses adjuvant arthritis in rats and intervenes cytokine-signaling between different types of synoviocytes.

Total glucosides of paeony (TGP) are active compounds extracted from the roots of Paeonia lactiflora Pall. In this study, we investigated the mechanisms of total glucosides of paeony (TGP) in the treatment of adjuvant arthritis (AA). AA in rats was established. Synoviocytes proliferation and activity of IL-1 were determined by 3-(4, 5-2dimethylthiazal-2yl) 2, 5-diphenyltetrazoliumbromide (MTT) assay. Tumor necrosis factor alpha (TNF-alpha) and prostaglandin E2 (PGE2) were measured by radioimmunoassay. Ultrastructure of synovioctes was observed under transmission electron microscope. Phosphorylation of c-Jun N-terminal kinase (JNK), extracellular regulating kinase (ERK) and p38 kinase and expression of matrix metalloproteinases (MMPs) were detected by Western blot analysis. TGP (25, 50 and 100 mg kg(-1), ig, days 14-21) inhibited secondary inflammatory reaction, bone destruction and ultrastructure change of synoviocytes in AA rats. The administration of TGP (50 and 100 mg/kg, ig, days 14-21) in AA rats significantly decreased the production of IL-1, PGE2 and TNF-alpha by macrophage-like synoviocytes (MLS). TGP (25 mg/kg) also decreased the production of PGE(2) by MLS in AA rats. Furthermore, the increased phosphorylation of MAPKs, cell proliferation, and MMPs expression in fibroblast-like synoviocytes (FLS) stimulated by supernatants of MLS in AA rats could also be inhibited by TGP (50 and 100 mg/kg, ig, days 14-21). The results suggest that TGP possesses anti-inflammatory effects by modulating the pro-inflammatory mediators production from MLS and phosphorylation of MAPKs from FLS.

Glucosides of Chaenomeles speciosa remit rat adjuvant arthritis by inhibiting synoviocyte activities.

AIM: To investigate the effects of Glucosides of Chaenomeles speciosa (GCS) on rat adjuvant arthritis (AA) and to clarify the role of synoviocytes in this process. METHODS: Complete Freund's adjuvant was used to induce AA in rats. Secondary paw swelling of AA rats was measured with MK-550 volume meter. The pain response and polyarthritis index were scored. Synoviocytes were separated by incubation of collagenase and trypsin, and morphological changes of synoviocytes were observed by transmission electron microscope. Interleukin-1 (IL-1) production was measured by thymocyte proliferation assay. Tumor necrosis factor (TNFalpha) and prostaglandin E2 (PGE2) production were determined by radioimmunoassay. RESULTS: There were significant secondary inflammatory reactions in AA rats. The morphology of synoviocytes from AA rats was changed, companying the elevation of the level of IL-1,TNFalpha, and PGE2 produced by synoviocytes from AA rats. GCS (60 and 120 mg/kg, ig, 8 d) suppressed secondary inflammatory paw swelling, pain response, and polyarthritis index. It also improved ultrastructural changes of synoviocytes and inhibited IL-1,TNFalpha, and PGE2 production in AA rats. The inhibitory effect of GCS 120 mg/kg was more evident than that of Actarit 60 mg/kg. CONCLUSION: GCS reduced the secondary inflammatory in AA rats, which is associated with prevention of ultrastructural changes of synoviocytes and inhibition of secretion of proimflammatory cytokines.