[Clinical efficacy of fire needling combined with cupping therapy on herpes zoster of acute stage and the effect on Th17/Treg cellular immune balance].

OBJECTIVE: To compare the clinical efficacy between the combined therapy of fire needling and cupping, and western medication on herpes zoster of acute stage, as well as the effects on Th17 and Treg cells and inflammatory factors, i.e. IL-10 and IL-17 in the peripheral blood. METHODS: Eighty patients with herpes zoster of acute stage were randomly divided into a combined therapy (fire needling plus cupping) group and a western medication group, 40 cases in each one. In the combined therapy group, the pricking and scattering techniques with fire needle were used at ashi points and Jiaji (EX-B 2) corresponding to the affected spinal segments; afterwards, cupping therapy was delivered. The combined treatment was given once daily. In the western medication group, valaciclovir hydrochloride tablet and vitamin B1 tablet were administered orally. The duration of treatment in each group was 10 days. Before each treatment from day 1 to day 10 and on day 11 , the score of symptoms and physical signs was observed in the two groups separately. Before each treatment from day 1 to day 10 and on day 11, 30, 60, the score of visual analogue scale (VAS) and skin lesion indexes were observed in the two groups. On day 60, the incidence of postherpetic neuralgia was recorded in the two groups. The levels of Th17 and Treg cells, Th17/Treg ratio in the peripheral blood, as well as serum levels of IL-10 and IL-17 were detected before and after treatment in the two groups. The clinical efficacy was compared between the two groups. RESULTS: From day 6 to day 10 during treatment and on day 11, the scores of symptoms and physical signs in the combined therapy group were lower than those of the western medication group (P<0.05, P<0.01). On day 3, day 6 to day 10 during treatment and day 11, day 30, VAS scores in the combined therapy group were lower than those of the western medication group (P<0.05, P<0.01). On day 60, the incidence of postherpetic neuralgia in the combined therapy group was lower compared with that in the western medication group (P<0.05). The blister arresting time and scabbing time in the combined therapy group were shorter than those of the western medication group (P<0.05). After treatment, the level of Th17, and Th17/Treg ratio in the peripheral blood, as well as the serum levels of IL-10 and IL-17 were all lower in comparison with those in the western medication group (P<0.05). The curative and remarkably effective rate was 82.5% (33/40) in the combined therapy group, higher than 62.5% (25/40) in the western medication group (P<0.05). CONCLUSION: The early application of fire needling combined with cupping therapy can effectively treat herpes zoster of acute stage, relieve pain, and reduce the incidence of postherpetic neuralgia, which may be related to reducing the levels of Th17 and Treg cells, and Th17/Treg ratio in the peripheral blood, as well as the serum levels of IL-10 and IL-17 so that the cellular immune balance is modulated.

SKF38393 prevents high glucose (HG)-induced endothelial dysfunction by inhibiting the effects of HG on cystathionine γ-lyase/hydrogen sulfide activity and via a RhoA/ROCK1 pathway.

BACKGROUND: Endothelial dysfunction plays a crucial role in diabetic vascular complications. A decrease in hydrogen sulfide (H2S) levels is increasingly becoming a vital factor contributing to high glucose (HG)-induced endothelial dysfunction. Dopamine D1-like receptors (DR1) activation has important physiological functions in the cardiovascular system. H2S decreases the dysfunction of vascular endothelial cells. However, no studies have reported whether DR1 protects the function of vascular endothelial cells by regulating H2S levels. AIM: The present study aimed to determine whether DR1 regulates the levels of endogenous H2S, which exerts protective effects against HG-induced injury of human umbilical vein endothelial cells (HUVECs) via Ras homolog gene family member A (RhoA)/Rho-associated coiled-coil containing kinase 1 (ROCK1) signalling. METHODS: HUVECs were exposed to HG (30 mM) or normal glucose (5.5 mM) after different treatments. Cell viability, proliferation and migration were measured by Cell Counting Kit-8, EdU cell proliferation assay, transwell assay and wound healing assay, respectively. H2S probe (7-Azido-4-Methylcoumarin) was used to detect levels of H2S. The intracellular calcium concentration ([Ca2+]i) were measured using Fluo-4 AM. The protein expressions were quantified by Western blot. RESULTS: We found that HG decreased the expression of DR1 and cystathionine γ-lyase (CSE) and H2S production. The DR1 agonist SKF38393 significantly increased DR1 and CSE expression and H2S production, whereas NaHS (a H2S donor) only increased CSE expression and H2S production but had no effect on DR1 expression. Meanwhile, SKF38393 further increased the [Ca2+]i induced by HG. In addition, HG reduced cell viability and the expression of Cyclin D1 and proliferating cell nuclear antigen and increased the expression of p21C⁢i⁢p/W⁢A⁢F-1, collagen I, collagen III, matrix metalloproteinase 9, osteopontin and α-smooth muscle actin and the activity of phosphorylated RhoA and ROCK1. SKF38393 and NaHS reversed these effects of HG. PPG (a CSE inhibitor) abolished the beneficial effect of SKF38393. These effects of SKF38393 were similar to those of Y-27632 (a ROCK inhibitor). CONCLUSION: Taken together, our results suggest that DR1 activation upregulates the CSE/H2S pathway by increasing the [Ca2+]i, which protects endothelial cells from HG-induced injury by inhibiting the RhoA/ROCK1 pathway.

[Effects of exogenous H2S on hepatic fibrosis in diabetic mice and its mechanism].

OBJECTIVE: To investigate the effects of exogenous hydrogen sulfide (H2S) on the hepatic fibrosis in diabetic mice and its mechanism. METHODS: Twenty-four C57 male mice (weight 22±2 g) were randomly divided into three groups (n=8): ① Normal control group (Control): Mice were intraperitoneally injected equal amount of normal saline, the injection time was the same as that of the experimental groups; ② Diabetes model groups (HG): Streptozotocin (STZ) was injected intraperitoneally once according to body weight (150 mg/kg) to establish diabetes model; ③ NaHS treatment groups (HG + NaHS): Mice were intraperitoneally injected with NaHS (100 µmol/L·kg·d) once a day for 12 consecutive weeks. The hepatocyte injury was detected by HE staining; the hepatic fibrosis was observed through Masson staining; the protein expressions of cystathionine - ß - synthetase (CBS), collagen-I (CoL-I), collagen-III (CoL-III) and matrix metalloproteinase-9 (MMP-9) were detected by Western blot. RESULTS: Compared with the control group, the damage and fibrosis of hepatocyte were significantly aggravated, the expression of CBS proteins was decreased (P＜0.01), and the expression levels of CoL-I, CoL-III and MMP-9 proteins were increased (P＜0.01) in the diabetic model group. Compared with the diabetic model group, the damage and fibrosis of hepatocyte were significantly lightened, the expression of CBS proteins was obviously increased (P＜0.01), and the expression levels of CoL-I, CoL-III and MMP-9 proteins were markedly decreased (P＜ 0.01). CONCLUSION: H2S inhibits the hepatic fibrosis in diabetic mice, and its mechanism is related to the decrease of collagen and matrix metalloproteinase-9.

[Professor LIN Guo-hua's experience in treatment of progressive muscular dystrophy with acupuncture].

Professor LIN Guo-hua's experience is introduced in treatment of progressive muscular dystrophy with acupuncture. It is believed that the pathogenesis of this disease is related to spleen and kidney deficiency, qi and blood insufficiency and malnutrition of tendon and muscle. The treatment is determined in terms of the pathogenesis and focuses on the regulation of spleen and kidney functions. The thinking of treatment is summarized as exerting the strong stimulation of acupuncture specially at the acupoints on the head, supplementing the sea of marrow, adjusting simultaneously the three yang meridians, rather than treating particularly yangming meridian and regulating qi in priority and considering the lung function for wei (flaccid) syndrome. Moreover, in clinical treatment, the acupoint thread-embedding therapy is commonly combined to ensure the significant therapeutic effect.

NPS2390, a Selective Calcium-sensing Receptor Antagonist Controls the Phenotypic Modulation of Hypoxic Human Pulmonary Arterial Smooth Muscle Cells by Regulating Autophagy.

BACKGROUND AND OBJECTIVES: Calcium-sensing receptor (CaSR) is known to regulate hypoxia-induced pulmonary hypertension (HPH) and vascular remodeling via the phenotypic modulation of pulmonary arterial smooth muscle cells (PASMCs) in small pulmonary arteries. Moreover, autophagy is an essential modulator of VSMC phenotype. But it is not clear whether CaSR can regulate autophagy involving the phenotypic modulation under hypoxia. METHODS: The viability of human PASMCs was detected by cell cycle and BrdU. The expressions of proliferation protein, phenotypic marker protein, and autophagy protein in human PASMCs were determined by western blot. RESULTS: Our results showed that hypoxia-induced autophagy was considerable at 24 h. The addition of NPS2390 decreased the expression of autophagy protein and synthetic phenotype marker protein osteopontin and increased the expression of contractile phenotype marker protein SMA-ɑ and calponin via suppressing downstream PI3K/Akt/mTOR signal pathways. CONCLUSIONS: Our study demonstrates that treatment of NPS2390 was conducive to inhibit the proliferation and reverse phenotypic modulation of PASMCs by regulating autophagy levels.

[Changes of myocardial function in diabetic rats and its mechanism].

OBJECTIVE: To investigate the role of calcium-sensing receptor (CaSR) in the decrease of cardiac function in type 2 diabetic rats. METHODS: Wistar rats were randomly divided into 3 groups including control, diabetic-4 week and diabetic-8 week groups. Rats in the diabetes group were fed with high-glucose and high-fat diet, and intraperitoneal injection of streptozocin (STZ,30 mg/kg) was conducted 4 weeks later to establish a type 2 diabetes model. Cardiac morphological changes were observed by HE staining, cardiac function was detected by echocardiography, and CaSR and PKC-αprotein expressions in cardiac tissue were detected by Western blot. RESULTS: Compared with the control group, the myocardium of diabetic rats showed irregular contraction zone, decreased expression of CaSR protein, increased expression of PKC-α protein, decreased systolic and diastolic functions, and gradually worsened with the prolongation of the course of the disease. CONCLUSION: Hyperglycemia inhibits the expression of CaSR protein in myocardium of diabetic rats by activating PKC-α, which can cause intracellular calcium disorder and lead to decreased cardiac function.

[Protective effects of exogenous H2S to the recovery of hypoxia post-conditioning on aged H9C2 cells and the underling mechanisms].

OBJECTIVE: To investigate the recovery of protective effects of exogenous hydrogen sulfide (H2S) on hypoxia post-conditioning in aged H9C2 cells and its mechanism. METHODS: H9C2 cells (cardiomyocytes line) were treated with 30 µmol/L hydrogen peroxide (H2O2) for 2 hours, then cultured for 3 days in order to induce cellular aging. Aged H9C2 cells were randomly divided into 5 groups (n=8):Control group (Control), hypoxia/reoxygenation group (H/R), H/R + NaHS group, hypoxia post-conditioning (PC) group, PC+NaHS group. H/R model:the cells were exposed to hypoxic culture medium (serum and sugar free medium, pH=6.8) for 3 hours and then cultured at normal condition for 6 hours. PC model:at the end of hypoxia for 3 hours, the cells were exposed to normoxic culture solution for 5 minutes, then the cells were placed in hypoxic solution for 5 minutes, the cycle above-mentioned was repeated 3 times and followed by reoxygenation for 6 hours. Advanced glycation end products (AGEs) content and caspase-3 activity were detected by ELISA. The cell viability was observed by cell counting kit-8 (CCK-8). The reactive oxygen species (ROS) levels were analyzed using 2, 7-dichlorodihydrofluorescein diacetate (DCFH-DA) staining. The apoptotic rate was determined through Hoechst 33342 staining. The mRNA levels of relative gene expression were detected by real-time PCR. RESULTS: Thirty µmol/L H2O2 induced H9C2 cell senescence while did not lead to apoptosis. Compared with control group, cell viability was decreased, the apoptotic rate、levels of ROS and the mRNA of caspase-3, caspase-9 and Bcl-2 were increased in H/R and PC groups (P<0.01). There were no differences in the above indexes between PC group and H/R group. Supplementation of NaHS increased cell viability and decreased apoptotic rate and oxidative stress. The effects of PC + NaHS on the above indexes were better than those of H/R+NaHS group. CONCLUSIONS: Exogenous H2S can restore the protective effect of PC on the aged H9C2 cells, and its mechanism is related to the inhibition of oxidative stress and apoptosis.

Exogenous spermine inhibits the proliferation of human pulmonary artery smooth muscle cells caused by chemically-induced hypoxia via the suppression of the ERK1/2- and PI3K/AKT-associated pathways.

Pulmonary vascular remodeling is a significant pathological feature of hypoxia-induced pulmonary hypertension (HPH), while pulmonary artery smooth muscle cell (PASMC) proliferation plays a leading role in pulmonary vascular remodeling. Spermine (Sp), a polyamine, plays a critical role in periodic cell proliferation and apoptosis. The present study was conducted to observe the association between hypoxia-induced PASMC proliferation and polyamine metabolism, and to explore the effects of exogenous Sp on PASMC poliferation and the related mechanisms. In the present study, PASMCs were cultured with cobalt chloride (CoCl2) to establish a hypoxia model, and Sp at various final concentrations (0.1, 1, 10 and 100 µM) was added to the medium of PASMCs 40 min prior to the induction of hypoxia. Cell proliferation was measured by 3-(4,5-dimethylthiazol­2­yl)­2,5­diphenyltetrazolium bromide (MTT) assay, cell counting kit-8 assay and 5-bromo­2'­deoxyuridine (BrdU) incorporation assay. Cell cycle progression was determined by flow cytometry, and the protein expression levels of spermidine/spermine N1-acetyltransferase (SSAT; the key enzyme in the terminal degradation of polyamine), ornithine decarboxylase (ODC; the key enzyme of polyamine biosynthesis), cyclin D1 and p27 were measured by western blot analysis. The results revealed that the proliferation of the PASMCs cultured with CoCl2 at 50 µM for 24 h markedly increased. The expression of ODC was decreased and the expression of SSAT was increased in the cells under hypoxic conditions. Exogenous Sp at concentrations of 1 and 10 µM significantly inhibited hypoxia-induced PASMC proliferation, leading to cell cycle arrest at the G1/G0 phase. In addition, Sp decreased cyclin D1 expression, increased p27 expression, and suppressed the phosphorylation of extracellular signal­regulated kinase 1/2 (ERK1/2), phosphatidylinositol 3-kinase (PI3K) and protein kinase B (AKT); however, the above-metioned parameters were not markedly affected by Sp at concentrations of 0.1 or 100 µM. These results suggest that hypoxia disrupts polyamine metabolism, and Sp at concentrations of 1 and 10 µM inhibits the increase in human PASMC proliferation caused by chemically-induced hypoxia via the suppression of the ERK1/2- and PI3K/AKT-associated pathways. This study thus offer new insight into the prevention and treatment of HPH.

[Effects of activation of dopamine type I receptor on the produc-tion of NO/NOS in ox-LDL activated THP-1 cells].

OBJECTIVE: To study the effect of excited dopamine type I receptor on the production of nitric oxide/nitric oxide synthase(NO/NOS)in ox-LDL activated THP-1 cells and the possible mechanism. METHODS: Cultured THP-1 cells activated by PMA were randomly assigned in the following groups:control group (control), oxidized low density lipoprotein group (ox-LDL), dopamine receptor 1(DR1) agonist group (SKF), DR1 antagonist group (SCH), ERK blocker group (PD98059). Oil Red O staining was used to identify the accumulation of cellular lipid. The levels of NO and NOS in the supernatant of THP-1 were assayed by nitrate reductase method. The protein expression of DR1, p-ERK and ERK were obtained by Western blot and immunity fluorescence. RESULTS: After 48 h of incubation of ox-LDL, accumulation of lipid in the cytoplasm was found in most THP-1 cells. Compared with control group, DR1 protein expression was reduced in ox-LDL-induced cells(P<0.01). Activation of DR1 agonist decrease the production of NO and iNOS(P<0.01), and PD98059 partly reversed the above effect. CONCLUSIONS: Activation of DR1 can inhibit the production of NO/NOS in ox-LDL-induced THP-1 cells, which may be related with ERK pathway.

[Decreased expression of calcium-sensing receptor involved in the progression of diabetic cardiomyopathy].

OBJECTIVE: To observe the dynamic expression of calcium-sensing receptor(CaSR) in myocardium of diabetic rats. METHODS: Thirty male Wistar rats were randomly divided into 3 groups including control, diabetic-4 week and diabetic-8 week groups(n = 10). The type 2 diabetes mellitus models were established by intraperitoneal injection of streptozotocin (STZ, 30 mg/kg) after high-fat and high-sugar diet for one month. The cardiac morphology was observed by electron microscope. Western blot analyzed the expression of CaSR, phospholamban (PLN), a calcium handling regulator, and Ca+-ATPase(SERCA) in cardiac tissues. RESULTS: Compared with control group, the expressions of CaSR and SERCA were decreased, while the expression of PLN was significantly increased in a time-dependent manner in diabetic groups. Meanwhile diabetic rats displayed abnormal cardiac structure. CONCLUSION: These results indicate that the CaSR expression of myocardium is reduced in the progression of DCM, and its potential mechanism may be related to the imnaired intracellular calcium homeostasis.

[Effects and mechanisms of low concentration dopamine on hydrogen peroxide-induced apoptosis in cultured neonatal rat cardiomyocytes].

OBJECTIVE: To study the effects of low concentration dopamine(DA) on hydrogen peroxide-induced apoptosis in cultured rat cardiomyocytes as well as the possible molecular mechanisms. METHODS: Cultured neonatal rat cardiomyocytes were randomly divided into the following groups: control group (control), hydrogen peroxide group (H2O2), pretreated with low concentration dopamine ( DA + H2O2), dopamine receptor l(DR1) antagonist group (DR1 + DA + H2O2), dopamine receptor 2(DR2) antagonist group (DR2 + DA + H2O2). The cell apoptosis was then assessed by MTT and flow cytometry. The cellular ultrastructure changes were observed by transmission electron micro- scope. The activity of lactate dehydrogenase(LDH )and superoxide dismutase (SOD) in cell medium was analyzed by colorimetry. The protein expressions of Cytochrone c, Caspase 3 and Caspase 9 were obtained by Western blot. RESULTS: Compared with hydrogen peroxide group, low concentration dopamine(10 µmol/L) decreased the apoptosis rate and the expression of protein of apoptosis related protein, enhanced SOD activity, decreased LDH activity. DR1 antagonist SCH-23390 treatment inhibited dopamine induced cardiac protective effect. DR2 antagonist haloperido treatment had no changes compared with dopamine group. CONCLUSION: Above findings indicate that low concentration dopanine inhibits apoptosis induced by hydrogen peroxide in neonatal rat cardiomyocytes, which is partly associated with the activation of DR1.

[The effects of DR2 on myocardial ischemic postconditioning and its underlying mechanisms].

OBJECTIVE: To study the effects of dopamin receptors-2 (DR2) on myocardial ischemic postconditioning and explore its underlying mechanisms. METHODS: The myocardial ischemic postconditioning (PC) model was established in cultured primary rat neonatal cardiomyocytes which were then randomly assigned in the following groups: Nomial control group, Isehemia/reperfusion (L'R) group, PC (ischemic postconditioning) group, PC + Bro (Bromocriptine, a DB2 antagonist) group, PC + Hal (Haloperidol, a DB2 repressor) and PC + Hal + Bro groups. The lactate dehydrogenase (LDH) and superoxide dismutase (SOD) activity and malondialdehyde (MDA) content in cell medium were analyzed by colorunetry. The cell ultrastructure changes were observed by transmission electron microscope. The cell apoptosis was analyzed using flowcytometiy. The protein expression level of D112 and activity of p-p38 and p-JNK were detected by Western blot. RESULTS: Compared with the nonnal control group, hR increased the protein expression level of DB2, enhanced LDH activity and MDA content, promoted cell injury and apoptosis, decreased SOD activity, up-regulated the activity of p-p38 and p-JNK. Compared with the hR group, although PC further increased the expression of DR2 protein, it decreased LDH activity and MDA content, cell injury and apoptosis, increased SOD activity, down-regulated activity of p-p38 and p-JNK. Bromocriptine treatment further enhanced PC-induced canlioprotective effect, yet Hal addition attenuated this enhancing effect exerted by bromocriptine. CONCLUSION: The activation of DB2 is involved in the protective effect of ischemic postconditioning on myocardial ischemia/reperfusion injury through down-regulating the activity of p-p38 and p-JNK.

Involvement of calcium-sensing receptors in hypoxia-induced vascular remodeling and pulmonary hypertension by promoting phenotypic modulation of small pulmonary arteries.

Phenotype modulation of pulmonary artery smooth muscle cells (PASMCs) plays an important role during hypoxia-induced vascular remodeling and pulmonary hypertension (PAH). We had previously shown that calcium-sensing receptor (CaSR) is expressed in rat PASMCs. However, little is known about the role of CaSR in phenotypic modulation of PASMCs in hypoxia-induced PAH as well as the underlying mechanisms. In this study, we investigated whether CaSR induces the proliferation of PASMCs in small pulmonary arteries from both rats and human with PAH. PAH was induced by exposing rats to hypoxia for 7-21 days. The mean pulmonary arterial pressure (mPAP), right ventricular hypertrophy index (RVI), the percentage of medial wall thickness to the external diameter (WT %), and cross-sectional total vessel wall area to the total area (WA %) of small pulmonary arteries were determined by hematoxylin and eosin (HE), masson trichrome and Weigert's staining. The protein expressions of matrix metalloproteinase (MMP)-2 and MMP-9, the tissue inhibitors of metalloproteinase (TIMP)-3, CaSR, proliferating cell nuclear antigen (PCNA), phosphorylated extracellular signal-regulated kinase (p-ERK), and smooth muscle cell (SMC) phenotype marker proteins in rat small pulmonary arteries, including calponin, SMα-actin (SMAα), and osteopontin (OPN), were analyzed by immunohistochemistry and Western blotting, respectively. In addition, immunohistochemistry was applied to paraffin-embedded human tissues from lungs of normal human and PAH patients with chronic heart failure (PAH/CHF). Compared with the control group, mPAP, RVI, WT % and WA % in PAH rats were gradually increased with the prolonged hypoxia. At the same time, the expressions of CaSR, MMP-2, MMP-9, TIMP-3, PCNA, OPN, and p-ERK were markedly increased, while the expressions of SMAα and calponin were significantly reduced in lung tissues or small pulmonary arteries of PAH rats. Neomycin (an agonist of CaSR) enhanced but NPS2390 (an antagonist of CaSR) weakened these hypoxic effects. We further found that the expression change of CaSR, PCNA, and SMC phenotypic marker proteins in PAH/CHF lungs was similar to those in PAH rats. Our data suggest that CaSR is involved in the pulmonary vascular remodeling and PAH by promoting phenotypic modulation of small pulmonary arteries.

[The protective effect of DR2 activation on hypoxia/reperfusion injury in the neonatal rat cardiomyocytes and related mechanism].

OBJECTIVE: To observe the effect of dopamine receptor (DR2) activation on hypoxia/reperfusion injury (HRI) in the neonatal rat cardiomyocytes, and to explore its mechanism. METHODS: The hypoxia/reperfusion (H/R) injury model was established in primarily cultured neonatal rat cardiomyocytes, and randomly assigned: control, H/R, bromocriptine (Bro) and haloperidol (Hal) groups. The cell apoptosis was detected using inverted microscope, transmission electron microscope and flow cytometry (FCM). The lactate dehydrogenase(LDH) and superoxide dismutase (SOD) activity and malondialdehyde (MDA) content in cell medium were analyzed. The expression of mRNA and protein of caspase-3, caspase-8, caspase-9, Fas, Fas-L, Cyt C and Bcl-2 were detected by RT-PCR and Western blot, respectively. RESULTS: Compared with the control group, apoptosis rate, LDH activity, MDA content and the expression of pro-apoptotic factors and anti-apoptotic factors were increased, but SOD activity was decreased in H/R group. Compared with the H/R group, all index above-mentioned were down-regulated or reversed in Bro-group, and had no obvious differences in Hal-group. CONCLUSION: The neonatal rat cardiomyocytes injury and apoptosis caused by hypoxia/reperfusion can be inhibited with DR2 activation, which mechanism is related to scavenging oxygen radical.

Increased expression of calcium-sensing receptors in atherosclerosis confers hypersensitivity to acute myocardial infarction in rats.

Acute myocardial infarction (AMI) is a leading cause of death worldwide. Most cases of AMI result from coronary atherosclerosis (AS). The pathogenic mechanisms underlying AS lesions and AMI are incompletely understood. Calcium-sensing receptors (CaSR) belong to a family of G-protein-coupled receptors. We previously discovered that CaSR was expressed in the heart tissue of adult rats. CaSR may contribute to AMI in AS. We initially established a rat model of AS by injection of vitamin D(3) and feeding with a high-fat diet. Isoproterenol (ISO) was used to induce AMI. The MB isoenzyme of creatine kinase (CK-MB), lactate dehydrogenase (LDH), cardiac troponin T (cTnT), tetrazolium chloride staining, and cardiac function parameters were selected as indicators of myocardial damage or necrosis. Cardiac apoptosis was analyzed by transferase dUTP nick-end labeling (TUNEL) assay. Expression of CaSR, Bcl-2, Bax, caspase-3, p-ERK1/2, p-JNK, and p-p38 were determined by Western blot analysis. Compared with the control group, levels of cTnT, CK-MB, and LDH; number of TUNEL-positive cells; and expression of CaSR, Bax, caspase-3, p-ERK1/2, p-JNK and p-p38, were significantly increased, whereas cardiac function and expression of Bcl-2 were decreased markedly in isoproterenol (ISO)-treated group (C/ISO) and AS groups. These changes were significant in the AS/ISO group than in the C/ISO group or AS group. The upregulation of CaSR during AS formation renders hypersensitivity to AMI. Activation of the pro-apoptotic mitochondria pathway and JNK-p38 MAPK pathway triggered by increased expression of CaSR may be one of molecular mechanisms underlying AMI in AS.

Involvement of calcium-sensing receptor in oxLDL-induced MMP-2 production in vascular smooth muscle cells via PI3K/Akt pathway.

Matrix metalloproteinase-2 (MMP-2) is constitutively expressed in vascular smooth muscle cells (VSMCs) and up-regulated in atherosclerotic lesion by various stimuli, such as oxidized low-density lipoprotein (oxLDL). Calcium-sensing receptor (CaSR) is also expressed in VSMCs, but it remains unclear whether CaSR is associated with overproduction of MMP-2 in VSMCs. In this study, the expression of MMP-2 was detected by real-time PCR and Western blot analysis, and the gelatinolytic activity of MMP-2 was measured using gelatin zymography. Our results showed that oxLDL enhanced MMP-2 expression and activity in rat aortic VSMCs in a time- and dose-dependent manner. In addition, CaSR expression was up-regulated by oxLDL. Manipulating CaSR function in these cells by NPS2390 (an antagonist of CaSR) or GdCl(3) (an agonist of CaSR) affected the oxLDL-induced MMP-2 production. In VSMCs, oxLDL stimulated the rapid activation of phosphatidylinositol 3-kinase (PI3K)/Akt signal pathway, as determined by Western blot analysis. Phosphorylation of Akt and MMP-2 production stimulated by oxLDL were attenuated by LY294002 (a specific inhibitor of PI3K). Activation of Akt was suppressed by NPS2390 but enhanced by GdCl(3). In contrast, oxLDL had no stimulatory effect on the phosphorylation of JNK, and pretreatment with SP600125 (an inhibitor of JNK) produced no significant effect on oxLDL-induced MMP-2 production. These results suggest that CaSR mediates oxLDL-induced MMP-2 production in VSMCs via PI3K/Akt signal pathway.

Decrease in calcium-sensing receptor in the progress of diabetic cardiomyopathy.

To observe the dynamic expression of calcium-sensing receptor (CaSR) in myocardium of diabetic rats and explore its role in diabetic cardiomyopathy (DCM), 40 male Wistar rats were randomly divided into 4 groups including control, diabetic-4 weeks, diabetic-8 weeks and spermine treatment groups (240 µM of spermine in drinking water). The type 2 Diabetes mellitus (DM) models were established by intraperitoneal injection of streptozotocin (STZ, 30 mg/kg) after high-fat and high-sugar diet for one month. The echocardiographic parameters were measured, cardiac morphology was observed by electron microscope and HE staining. The intracellular calcium concentration ([Ca(2+)](i)) was detected by laser-scanning confocal microscope. Western blot analyzed the expression of CaSR, protein kinase C α(PKC-α) and calcium handling regulators, such as phospholamban (PLN), Ca(2+)-ATPase (SERCA), and ryanodine receptor (RyR). Compared with control group, [Ca(2+)](i) and the expression of CaSR, RyR and SERCA/PLN were decreased, while PKC-α and PLN were significantly increased in a time-dependent manner in diabetic groups. Meanwhile diabetic rats displayed abnormal cardiac structure and systolic and diastolic dysfunction, and spermine (CaSR agonist) could prevent or slow its progression. These results indicate that the CaSR expression of myocardium is reduced in the progress of DCM, and its potential mechanism is related to the impaired intracellular calcium homeostasis.

Role of dopamine D2 receptors in ischemia/reperfusion induced apoptosis of cultured neonatal rat cardiomyocytes.

BACKGROUND: Myocardial ischemia/reperfusion injury is the major cause of morbidity and mortality for cardiovascular diseases. Dopamine D2 receptors are expressed in cardiac tissues. However, the roles of dopamine D2 receptors in myocardial ischemia/reperfusion injury and cardiomyocyte apoptosis are unclear. Here we investigated the effects of both dopamine D2 receptors agonist (bromocriptine) and antagonist (haloperidol) on apoptosis of cultured neonatal rat ventricular myocytes induced by ischemia/reperfusion injury. METHODS: Myocardial ischemia/reperfusion injury was simulated by incubating primarily cultured neonatal rat cardiomyocytes in ischemic (hypoxic) buffer solution for 2 h. Thereafter, these cells were incubated for 24 h in normal culture medium. RESULTS: Treatment of the cardiomyocytes with 10 µM bromocriptine significantly decreased lactate dehydrogenase activity, increased superoxide dismutase activity, and decreased malondialdehyde content in the culture medium. Bromocriptine significantly inhibited the release of cytochrome c, accumulation of [Ca2+]i, and apoptosis induced by ischemia/reperfusion injury. Bromocriptine also down-regulated the expression of caspase-3 and -9, Fas and Fas ligand, and up-regulated Bcl-2 expression. In contrast, haloperidol (10 µM) had no significant effects on the apoptosis of cultured cardiomyocytes under the aforementioned conditions. CONCLUSIONS: These data suggest that activation of dopamine D2 receptors can inhibit apoptosis of cardiomyocytes encountered during ischemia/reperfusion damage through various pathways.

The functional expression of extracellular calcium-sensing receptor in rat pulmonary artery smooth muscle cells.

BACKGROUND: The extracellular calcium-sensing receptor (CaSR) belongs to family C of the G protein coupled receptors. Whether the CaSR is expressed in the pulmonary artery (PA) is unknown. METHODS: The expression and distribution of CaSR were detected by RT-PCR, Western blotting and immunofluorescence. PA tension was detected by the pulmonary arterial ring technique, and the intracellular calcium concentration ([Ca2+]i) was detected by a laser-scanning confocal microscope. RESULTS: The expressions of CaSR mRNA and protein were found in both rat pulmonary artery smooth muscle cells (PASMCs) and PAs. Increased levels of [Ca2+]o (extracellular calcium concentration) or Gd3+ (an agonist of CaSR) induced an increase of [Ca2+]i and PAs constriction in a concentration-dependent manner. In addition, the above-mentioned effects of Ca2+ and Gd3+ were inhibited by U73122 (specific inhibitor of PLC), 2-APB (specific antagonist of IP3 receptor), and thapsigargin (blocker of sarcoplasmic reticulum calcium ATPase). CONCLUSIONS: CaSR is expressed in rat PASMCs, and is involved in regulation of PA tension by increasing [Ca2+]i through G-PLC-IP3 pathway.

The calcium-sensing receptor mediates hypoxia-induced proliferation of rat pulmonary artery smooth muscle cells through MEK1/ERK1,2 and PI3K pathways.

Activation of the calcium-sensing receptor (CaSR) leads to an increase of intracellular calcium concentration and alteration of cellular activities. High level of intracellular calcium is involved in hypoxia-induced proliferation of pulmonary arterial smooth muscle cells (PASMCs). However, whether the CaSR is expressed in PAMSCs and is related to the hypoxia-induced proliferation of PASMCs is unclear. In this study, the expression and distribution of CaSRs were detected by RT-PCR, western blotting and immunofluorescence; the intracellular concentration of free calcium ([Ca(2+) ](i) ) was determined by confocal laser scanning microscopy; cell proliferation was tested using an MTT and BrdU incorporation assay; cell cycle analysis was carried out using a flow cytometric assay; and the expression of proliferating cell nuclear antigen (PCNA), extracellular signal-regulated protein kinase 1,2 (ERK1,2) and AKT were analysed by western blotting. We observed that both CaSR mRNA and protein were expressed in rat PASMCs. Lowering of oxygen from 21% to 2.5% led to increased [Ca(2+) ](i) and CaSR expression. This condition of hypoxia also stimulated PASMCs proliferation accompanying with increased phosphorylation of ERK1,2 and AKT. GdCl(3) (an agonist of CaSR) or NPS2390 (an antagonist of CaSR) amplified or weakened the effect of hypoxia, respectively. PD98059 (a MEK1 inhibitor) or LY294002 (a PI3K inhibitors) decreased the up-regulation of PCNA expression and the increase of the cell proliferation index induced by hypoxia and GdCl(3) in PASMCs. Our results suggest that CaSR is expressed in rat PASMCs, and that CaSR activation through MEK1/ERK1,2 and PI3 kinase pathways is involved in hypoxia-induced proliferation of PASMCs.