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

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

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。

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 nag 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 sig- nificant 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.