清醒大鼠急性高血糖模型的建立及其“肾毒性”损伤特点及机制研究

目的 建立大鼠清醒状态下急性高血糖模型,观察急性高血糖引起肾损伤的特点,并探讨其可能机制.方法 应用随机数字表法将Sprague-Dawley大鼠分为高糖组和对照组(n=10),颈静脉置管术后行高葡萄糖钳夹实验建立急性高血糖模型.术后第5天高糖组经颈静脉置管泵入50％葡萄糖溶液,使血糖维持于16 ～ 18 mmol/L;对照组以同等速度泵入生理盐水,实验持续6h,留取24 h尿液后处死大鼠并取材.光镜和透射电镜观察肾脏结构损伤,检测肾功能、尿微量白蛋白(UMA)及肾损伤分子-1(KIM-1)等肾损伤指标,检测超氧化物歧化酶(SOD)、丙二醛及8-羟基-2'-脱氧鸟苷(8-OHdG)评估氧化应激水平.结果 高糖组出现明显肾脏结构和功能损伤.结构上可见近曲小管细胞肿胀,细胞内线粒体肿胀、排列紊乱;与对照组相比,高糖组24 h UMA、KIM-1及中性粒细胞明胶酶相关载脂蛋白(NGAL)均显著升高(t=-2.969、-2.220、-2.791,P均＜0.05),而血清及肾组织SOD活性明显下降(t=2.537、2.599,P均＜0.05),血清丙二醛、肾组织丙二醛及尿8-OHdG明显升高(t=-2.532、-2.600、-2.968,P均＜0.05).结论 成功建立大鼠急性高血糖模型.急性高血糖可导致肾脏结构和功能损伤,以肾小管损伤为主,氧化应激及线粒体损伤参与急性高血糖“肾毒性”损伤的发生、发展.

The modeling of acute hyperglycemia in conscious rats and the kidney damaging characteristics and mechanism

Objective To establish the modeling of acute hyperglycemia,observe the characteristics of acute hyperglycemia induced kidney damages,and to explore its possible mechanisms.Methods Sprague-Dawley rats were divided into hyperglycemia group and control group according to the random number table,and underwent catheterization through jugular vein before acute hyperglycemic clamp to establish the modeling of acute hyperglycemia.Rats in hyperglycemia group were infused with 50％ glucose solution at the 5th day after the surgery to maintain the blood glucose between 16 and 18 mmol/L,and rats in control group were infused with normal saline for 6 hours.Then 24-hour urine was collected and the rats were killed.Renal structure alterations were observed under optical and transmission electron microscope,renal injury were evaluated by detecting renal function,urinary microalbumin (UMA) and kidney injury molecule-1 (KIM-1),and oxidative stress activation were assessed by detecting superoxide dismutase(SOD),malondialdehyde (MDA) and 8-hydroxy-2'-deoxyguanosine (8-OHdG).Results The renal morphologic and functional injuries were found in hyperglycemia group,and severe damages were found in tubular epithelial cells including the enlargement of epithelial cells,the swelling and disarrangment of mitochondria of epithelial cells.Compared with control group,UMA,KtM-1,and neutrophil gelatinase-associated lipocalin (NGAL) level were increased significantly in hyperglycemia group (t =-2.969,-2.220,-2.791,all P ＜ 0.05).Moreover,compared with control group,serum and renal SOD activity were decreased (t =2.537,2.599,all P ＜ 0.05),while serum MDA,renal MDA and urinary 8-OHdG level were increased significantly in hyperglycemia group(t =-2.532,-2.600,-2.968,all P ＜ O.05).Conclusions The acute hyperglycemia model in healthy rats are set up successfully.Acute hyperglycemia causes significant damages of renal morphology and functions,especially to tubular epithelial cells,mitochondria injuries and oxidative stress activation may play important roles in acute hyperglycemia induced kidney injuries.