中文摘要：

目的：观察硫化氢（H_2S）对1型糖尿病大鼠膈肌收缩功能的影响。方法：将32只雄性SD大鼠随机分为正常组（NC组）、糖尿病组（DM组）、NaHS治疗组（DM＋NaHS组）和NaHS对照组（NaHS组）。采用腹腔注射链脲佐菌素的方法制备大鼠糖尿病模型,造模成功后,DM＋NaHS组和NaHS组大鼠腹腔注射NaHS溶液28μmol/kg干预治疗。8周后,利用离体灌流大鼠膈肌条的方法,测定单收缩张力（Pt）、最大强直张力（Po）和张力最大上升/下降速率（±dT/dtmax）;电镜观察膈肌超微结构变化;计算大鼠膈肌质量/体质量（DW/BW）比值;测定膈肌组织琥珀酸脱氢酶（SDH）、乳酸脱氢酶（LDH）和肌质网钙泵（SERCA）活性;RT-PCR检测膈肌SERCA和受磷蛋白（PLB）mRNA的表达。结果：与NC组比较,NaHS组各项指标均无明显差异（P〉0.05）;而DM组膈肌Pt,Po和±dT/dtmax明显降低,膈肌超微结构损伤明显,DW/BW明显下降,膈肌组织SDH,LDH,SERCA活性和SERCA mRNA表达明显降低,PLB mRNA表达明显升高（均P〈0.05）。与DM组比较,DM＋NaHS组膈肌收缩功能和超微结构明显改善,DW/BW增高,膈肌组织SDH,LDH,SERCA活性和SERCA mRNA表达明显升高,PLB mRNA表达明显下降（均P〈0.05）。结论：外源性补充H_2S可以增强1型糖尿病大鼠膈肌的收缩能力,其机制可能与调节膈肌生物酶活性及钙调控蛋白的基因表达相关。

英文摘要：

Objective：To investigate the effects of hydrogen sulfide（H_2S） on contraction capacity of diaphragm in type 1 diabetic rats.Methods：Thirty-two male SD rats were randomly divided into a normal group（NC）,a diabetic group（DM）,a NaHS treatment group（DM＋NaHS） and a NaHS group（NaHS）（n=8）.Intraperitoneal injection of streptozotocin was utilized to establish diabetic rat model.After the modeling,the rats in the DM＋NaHS and the NaHS groups were intraperitoneally injected with28 μmol/kg NaHS solution.8 weeks later,the diaphragm contractility was assessed by isolated draphragm strips perfusion.The peak twitch tension（Pt）,maximum tetanic tension（Po） and maximal rates of contraction/relaxation（±dT/dtmax） were determined.The alterations in diaphragm ultrastructure were observed under electron microscopy.The diaphragm weight/body weight（DW/BW） was measured.The activities of succinic dehydrogenase（SDH）,lactate dehydrogenase（LDH） and sarcoplasmic reticulum Ca~（2＋） ATPase（SERCA） were analyzed by spectrophotometric method.The mRNA levels of SERCA and prospholamban（PLB） in diaphragm were detected by RT-PCR.Results：Compared with the NC group,there was no significant change in all measured index in the NaHS group（P〈0.05）,while Pt,Po and ±dT/dtmax were significantly decreased in the DM group（P〈0.05）.Transmission electron microscopy revealed obvious ultrastructural changes in the diaphragm.The DW/BW ratio and the activities of SDH,LDH and SERCA were decreased.The SERCA mRNA was decreased,while PLB mRNA was increased.Compared with the DM group,the diaphragm contractility and ultrastructure damage were improved in the DM＋NaHS group.The DW/BW ratio and the activities of SDH,LDH and SERCA were increased.The SERCA mRNA was increased,while PLB mRNA was decreased（all P〈0.05）.Conclusion：H_2S can enhance the contraction capacity of diaphragm in type 1 diabetic rats,which is involved in regulating the activities of biological enzymes and the gene expr