硫辛酸对大鼠糖尿病角膜病变的保护作用

目的探讨消旋-硫辛酸(LA)对大鼠糖尿病角膜病变的抑制作用。方法将37只7周龄Brown-Norway(BN)系大鼠随机分为对照组(CTL组)、糖尿病组(DM组)和治疗组(LA组)。2%链脲霉素(STZ)尾静脉注射制作糖尿病组和治疗组的糖尿病模型,治疗组大鼠饲料中添加0.3%LA。测定体重、食量、血糖值作为评价全身状态的指标,并在麻醉剂点眼及紫外线照射的条件下观察3组大鼠角膜上皮损伤程度及LA的修复作用。结果 CTL组的存活率是100%,DM组及LA组的存活率在发病5个月时分别为36%和71%。平均体重的顺序为CTL组>LA组>DM组,摄食量则为DM组>CTL组>LA组。在未施加干预因素的情况下,DM组和LA组自糖尿病诱发后3个月开始观察到了较正常对照组明显的角膜损伤,损伤程度DM组>LA组,但组间差异未见统计学意义。麻醉剂点眼后CTL、DM、LA组的角膜损伤值分别是4.66±0.85、6.51±1.81、5.99±2.42。DM组和LA组与点眼前相比均有显著的上升,但点眼后比较两组角膜损伤值未见统计学差异。紫外线照射联合点眼剂治疗后,CTL组、DM组、LA组的角膜损伤值分别为4.56±0.47、5.8±1.49、4.96±0.63。各组间差异均有统计学意义(P<0.05)。血糖值的顺序为DM组>LA组>CTL组,三组间差异均有显著意义(P<0.01)。结论糖尿病大鼠角膜上皮经麻醉剂点眼及紫外线照射后损伤修复延迟,而口服LA可有效降低STZ所致糖尿病大鼠的血糖浓度,抑制角膜病变的发生。LA在角膜中的生化特性有待进一步的研究。

Protective effect of lipoic acid on streptozotocin-induced diabetic keratopathy in rats

Objective To investigate the protective effect of DL-lipoic acid（LA） on streptozotocin-induced diabetic keratopathy in rats.Methods 37 female Brown-Norway（BN） rats of 7-week-old were divided into 3 groups comprising of the control group（CTL group）,diabetic mellitus group（DM group） and diabetic mellitus treated with 0.3% LA in diet（LA group）.Diabetes was induced by a single caudal vein injection of 2% streptozotocin.Powdered food mixed with 0.3% LA was given in LA group.To assess the general body state of the rats,we observed the changes of weight,daily diet amount and blood glucose level in rats.We observed the keratopathy caused by 0.4% Benoxil eyedrops and ultraviolet ray irradiation plus vitamin B2 interval eyedrops,and investigated LA＇s protective effect on the corneal injury.Results The survival rates in 3 groups were CTL 100%,DM 36% and LA 71% respectively.The mean body weight was DMCTLLA,and the daily diet amount was DMCTLLA.EAS-1000 scanning revealed severe corneal injury in DM,mild in LA,and no in CTL 3rd month after injection of 2% streptozotocin.The injury severity level was DMLA,but with no significant difference between 2 groups.Corneal injury values by anesthetic eyedrops were 4.66±0.85 in CTL group,6.51±1.81 in DM group,5.99±2.42 in LA group.Corneal injury values of DM and LA groups significantly increased after anesthetic eyedrops,but with no significant difference between 2 groups.Corneal injury values by ultraviolet ray irradiation plus vitamin B2 interval eyedrop were 4.56±0.47 in CTL group,5.8±1.49 in DM group,4.96±0.63 in LA group with significant difference between each 2 groups（0.05）.Blood glucose level was DMLACTL group（0.01）.Conclusion LA prevented diabetes-induced impairment and repair delay in rats＇cornea and effectively reduced STZ-induced blood glucose and inhibited diabetic keratopathy in rats.