糖尿病大鼠晶状体高糖代谢记忆机制的研究

Study on the mechanism of metabolic memory in the lens of diabetic rats

目的观察糖尿病大鼠在高血糖状态下晶状体形态及上皮细胞凋亡的变化，探讨晶状体是否存在高糖代谢记忆及其发生的机制。方法动物实验研究。对2012年7月至2013年4月将40只雄性SD大鼠，按概率随机分为正常对照组（N）和实验组。用链脲佐菌素（STZ）制作糖尿病模型，分为无代谢记忆组（NM）、代谢记忆组（MM）、糖尿病组（DM）。每周测体重、血糖，观察晶状体形态，12周取材用TUNEL法检测晶状体上皮凋亡细胞，计算凋亡百分率。结果N组和NM组晶状体全程保持透明；MM组在后6周中，晶状体混浊度逐渐加深。N组与NM组的LEC凋亡百分率差异无统计学意义（P〉0．05）；MM组与NM组相比较、DM组与NM组相比较，其LEC凋亡百分率的差异具有统计学意义（P〈0．01）。结论大鼠晶状体存在高糖代谢记忆效应。晶状体上皮细胞的凋亡途径参与了高糖代谢记忆，早期控制血糖，可以防止LEC的凋亡；长期处于高血糖状态后，即使后期血糖水平降低，LEC仍持续凋亡。

Objective To observe morphologic changes of lens and apoptotic characteristics of lens epithelial cells （LEC） in diabetic rats, to investigate whether metabolic memory effects on lens and discuss its mechanisms. Methods Male Sprague-Dawley （SD） rats were randomized into nor- mal （N） group and experimental groups. The experimental groups were induced by Streptozotocin （STZ） and randomized into the non-metabolic memory （NM） group, the metabolic memory （MM） group and the diabetic mellitus （DM） group. Body weight and blood glucose were monitored and morphology of lens were observed weekly. Samples of lens were collected on 12th week, apoptosis of LEC was monitored by TUNEL staining and percentage of apoptotic LEC was calculated. Re- suits The lens in N group and NM group had maintained transparent; the lens in MM group were aggravated during 6 weeks of blood glucose good control that followed 6 weeks of poor control. Ac- cording to the percentage of apoptotic LEC, there was no statistical significance between N group and NM group （P 〉0.05）; there was statistical significance between MM group and NM group, DM group and NM （P 〈0.01）. Conclusions Metabolic memory effects on lens of diabetic rats. Apopto- sis of LEC contributes to metabolic memory, the early good glycemic control can suppress apoptosis of LEC; if good glycemic control is established after a profound period of poor glycemic control, and apoptosis activation of LEC is still sustained.