| Objectives:To investigate the relationship between the changes of sigma-1receptor and pro NGF in IL-6 or hypoxiare/oxygenation induced myocardial injury and apoptosis.Methods:1.The IL-6 induced myocardial injury model was constructed in neonate rats.Myocardial cells were isolated from neonatal SPF SD rats,followed by culture for 48 hours.The cells were counted and were randomly divided into the normal group(Nor group),the IL-6 group-1(400 μg/L),the IL-6 group-2(800 μg/L)and the IL-6 group-3(1200 μg/L),respectively.Cells in the normal group were maintained in an incubator with normal oxygen at 37°C for 24 hours.However,cells in the other three groups were firstly treated with different concentrations of IL-6,followed by culture for 24 hours with the same condition of the normal group.At the end of 24 h,the apoptosis rate of cardiomyocytes was detected by flow cytometry in each group.The concentrations of groups whose apoptosis rate reached50% were set as the intervention concentrations of subsequent IL-6 induced myocar dial injury.2.Myocardial cells were isolated from neonatal SPF SD rats,followed by culture for 48 hours.The cells were counted and were randomly divided into the normal group(Nor group),the IL-6 group,the hypoxia/reoxygenation group(H/R group)and the IL-6+H/R group,respectively.Cells in the normal group weremai ntained in an incubator at 37°C for 24 hours;cells in the IL-6 group were firstly treated with 800 μg/L IL-6,followed by culture with the same condition of the nor mal group;cells in the H/R group were treated with hypoxia for 8h and reoxygena tion for 16h;and cells in the IL-6+H/R group were firstly treated with IL-6,follow ed by the same treatment as the H/R group.At the end of 24 h,the apoptosis rate of cardiomyocytes was detected by flow cytometry in each group.The m RNA expression of pro NGF、p75-NTR、sortilin and sigma-1receptor was detecte d by Q-PCR,and the protein expression of pro NGF was detected by western blot.Results:1.The apoptosis rate of cardiomyocytes in each group: compared with the Nor group,the apoptosis rate of the IL-6 group,the H/R group and the IL-6+H/R group were obviously higher(P<0.05).Among the three elevated groups,the IL-6+H/R group was statistically higher than that of the IL-6 group and the H/R group(P<0.05).Meanwhile,the IL-6 group was significantly higher than the H/R group(P<0.05).2.Changes of the m RNA expression of pro NGF、p75NTR、sortilin and si gma-1 receptor in cardiomyocytes of neonate rats treated with IL-6 and H/R:compared with the Nor group,the expression of the above molecules was significan tly elevated in the IL-6 group,the H/R group and the IL-6+H/R group(P<0.05).At the same time,the m RNA expression of pro NGF、p75NTR and sigma-1 receptor of the IL-6 group was obviously lower than the IL-6+H/R group,but was statistical ly higher than that of the H/R group(P<0.05).However,no statistically significant difference was found in sortilin among the IL-6 group,the H/R group and the IL-6+H/R group(P>0.05).3.Changes of the protein expression of pro NGF in cardiomyocytes of neon ate rats treated with IL-6 and H/R:the protein expression of pro NGF of the H/R group was statistically higher than the Nor group,the IL-6 group and the IL-6+H/R group(P<0.05).However,there was no significant difference between the Nor group,the IL-6 group and the IL-6+H/R group(P>0.05).Conclusion:1.IL-6 or H/R could increase the m RNA expression of pro NGF、p75-NTR、sortilin and sigma-1 receptor.Moreover,H/R rather than IL-6 could up-regulate the protein expression of pro NGF.2.IL-6 or H/R could induce apoptosis of cardiomyocytes in neonatal rats,and the underlying mechanism might be related to the up-regulated m RNA expression of sigma-1 receptor,p75 NTR and sortilin.3.Pro NGF participated in the cardiomyocyte apoptosis induced by H/R in neonatal rats,and the apoptosis induced by IL-6 might not be related to this.4.IL-6 and H/R exhibited an additive effect on the induction of cardiomyocyte apoptosis in neonatal rats. |
