黄芪多糖对2型糖尿病早期大鼠视网膜Muller细胞Kir2.1表达的影响

目的:探讨黄芪多糖对链脲佐菌素(STZ)诱导的2型糖尿病大鼠早期视网膜Muller细胞Kir2.1表达的影响。方法:雄性SPF级SD大鼠随机分为:正常对照组(C组,n=10),黄芪多糖对照组(CA组,n=10),饲以正常饲料;通过高脂饮食加小剂量STZ诱导复制2型糖尿病大鼠模型,将血糖>13.9 mmol/L者随机分为糖尿病组(DM组,n=8)及黄芪多糖治疗组(DA组,n=8)。治疗前后观察血糖、口服葡萄糖耐量变化。从4组大鼠视网膜提取总mRNA,逆转录聚合酶链反应(RT-PCR)方法检测Kir2.1 mRNA的表达。结果:DM组血糖显著高于C组,同时伴有明显的糖耐量下降(P<0.01),经黄芪多糖治疗8周后,DA组血糖降低,与DM组比较糖耐量改善(P<0.01)。RT-PCR扩增的Kir2.1 cDNA产物在DM组表达比在C组下降,而在CA组表达较DM上升(P<0.05),但在C组与CA组中未出现这种显著性的改变(P>0.05)。结论:黄芪多糖能够降低血糖,糖尿病大鼠早期视网膜Muller细胞Kir2.1蛋白表达下降,而黄芪多糖对于逆转这一早期的改变可能起到一定作用,从而起到减少糖尿病视网膜病变发病率的作用。

Effects of Astragalus Polysaccharide on the Expression of Kir2.1 of Muller Cells of Retina in STZ-Induced Diabetes Mellitus Rats

Objective: To investigate the effects of astragalus polysaccharide(APS) on the kir2.1 expression of Muller cells of STZ-induced type 2 diabetes mellitus(T2DM) rats.Methods: Male SD rats(SPF,n=44) were randomized to four groups: control group(C,n=10),APS control group(C APS,n=10),diabetic group(DM,n=8) and APS treated group(DM APS,n=8) which were established by high fat feeding with small dosage STZ injection(25 mg/kg).Half of diabetic and normal rats was administered with APS(700 mg per kilogram per day) for 8 weeks.Blood glucose and oral glucose tolerance test was a observed pre-and post-APS therapy.By using RT-PCR,amplified cDNA products by RT-PCR for Kir2.1 were detected.Results: Compared with C group,there was a significant increase in blood glucose level and marked derease in oral glucose tolerance test in diabetic rats(P<0.01) which was alleviated by the treatment with APS for 8 weeks(P<0.01).While such changes didn't occur in normal SD rats treated with APS.By using RT-PCR,the expression of Kir2.1 mRNA was down-regulated in the retina Muller cells of STZ-induced T2DM rats.After APS therapy for 8 weeks,the expression of Kir2.1 mRNA was significant higher than those in the Muller cells of STZ-induced T2DM rats.However,these significant alternations did not occur in the two non-diabetic control groups.Conclusion: The expression of Kir2.1 of Muller cells decreases in STZ-induced T2DM rats,and APS may have a protective effect on Muller cells so as to reduce the morbidity of diabetic retinopathy.