沙格列汀对糖尿病大鼠肝脏组织凋亡因子Bcl-2、Bax表达的影响

Effect of saxagliptin on expression of Bcl-2 and Bax in liver tissues of rats with diabetes mellitus

目的研究沙格列汀对糖尿病大鼠血糖指标及肝脏组织凋亡因子Bcl-2、Bax表达水平的影响。方法 45只雄性健康Wistar大鼠随机分为正常对照组(NC组)、糖尿病对照组(DM组)及沙格列汀干预组(Sax组),除NC组外,其余两组采用高糖高脂饮食联合腹腔注射链脲佐菌素(STZ)制备糖尿病大鼠模型;成功后Sax组给每日灌胃沙格列汀溶液(10 mg·kg-1·d-1)6周,余两组给予同体积生理盐水。检测三组大鼠空腹血糖(FBG)、空腹胰岛素(FINS)水平,计算胰岛素抵抗指数(HOMA-IR);透射电镜观察肝细胞超微结构;Western blot检测凋亡蛋白Bcl-2、Bax在肝组织的表达情况。两组间比较采用单因素方差分析,独立样本t检验,P<0.05为差异有统计学意义。结果 DM组大鼠FBG为(23.07±4.04)mmol/L、FINS为(16.90±0.54)m IU/L、HOMA-IR为17.32±0.32,Sax组大鼠FBG为(9.62±1.18)mmol/L、FINS为(10.45±0.31)m IU/L、HOMA-IR为4.47±0.46,Sax组FBG、FINS、HOMA-IR均显著降低(P<0.05)。透射电镜下,DM组肝细胞粗面内质网水肿、离散,线粒体数目减少,结构紊乱。Sax组肝细胞内质网围绕核膜排列整齐,线粒体结构较清晰、数目增多。Western blot结果显示:与NC组相比,DM组大鼠肝脏中Bax表达增多,差异有统计学意义(t=-3.00,P<0.05),DM组肝脏中Bcl-2表达水平增高,但与NC组比较,差异无统计学意义(t=0.25,P>0.05)。与DM组大鼠比较,Sax组大鼠肝脏组织中Bax表达水平下降,差异有统计学意义(t=15.13,P<0.05)。结论沙格列汀可能通过促进糖尿病大鼠肝脏中Bcl-2表达、抑制Bax表达,从而抑制细胞凋亡,减轻线粒体损伤,调节血糖代谢。

Objective To observe the effect of saxagliptin(Sax) on the expression of Bcl-2 and Bax in liver tissues of rats with diabetes mellitus. Methods 45 male Wistar rats were divided into three groups randomly: normal group(NC group), diabetes mellitus control group(DM group) and Sax intervention group(Sax group). Diabetes mellitus were induced by feeding the high sugary and high fat diet and streptozotocin injection, which were treated with Sax(daily dose of 10 mg/kg) gavage for 6 weeks, using saline as the control. After the treatment, fasting blood glucose(FBG), fasting insulin(FINS) and insulin resistance index(HOMA-IR) were evaluated in all the rats, and the expressions of Bcl-2 and Bax in the liver tissues were detected with Western blot, to observe the ultrastructure of liver tissues with transmission electron microscope. Comparison between the two groups used single factor analysis of variance, independent samples t test, P<0.05 for the difference was statistically significant. Results The levels of FBG, FINS and HOMA-IR in DM group rats were(23.07±4.04)mmol/L,(16.90±0.54)m IU/L and 17.32±0.32, compared with the DM group, Sax intervention significantly reduced FBG [(9.62±1.18)mmol/L], FINS [(10.45±0.31)m IU/L] and HOMA-IR(4.47±0.46)(P<0.05). Under the transmission electron microscopy, rough endoplasmic reticulum edema of hepatic tissues, the number of mitochondria was reduced and the structure of mitochondria was in disorder in DM group. However, in Sax group, rough endoplasmic reticulum arranges neatly around the nuclear membrane, the number of mitochondria was more than DM group and the structure of mitochondria was clear. Compared with NC group, expression of Bax in DM group increased, the difference was statistically significant(t=-3.00, P<0.05). The expression of Bcl-2 in DM group increased also, but compared with NC group, there was no statistically significant difference(t=0.05, P>0.05). Compared with DM group, the level of Bax in Sax group decreased, the difference was statistically significant(t=15.13, P<0.05). Conclusion Sax shows good therapeutic effect in diabetes mellitus possibly by regulating the expression of apoptosis-related proteins(promoting the expression Bcl-2 and inhibiting the expression of Bax), alleviating hepatic oxidative stress and mitochondrial injury.