Objective To investigate molecular mechanisms of renal cell apoptosis on CIAKI in vivo, especially the involvement of Akt/ mTOR signal pathways. Methods Diabetic Sprague-Dawley rats were induced by intraperitoneal injection of streptozotocin. Ten weeks later the normal and diabetic rats were administered 60% meglumine diatrizoate ( DTZ) or normal saline ( 10 ml/ kg) injection for two days continuously. 24 h after the operation, the rats were killed, stored blood samples for examining blood creatinine and kidneys for immunohistochemistry and western blotting analysis. The expression of caspase-3 in the kidney was investigated by immunohistochemistry. Meanwhile, quantitative analysis of the Bcl-2, Bax, upstream signal molecule p-Akt and p-mTOR protein expression by western blotting was used to study renal cell apoptosis on CIAKI. Results Compared with diabetic group (D group), the serum creatinine was significantly increased in diabetes + contrast media (DTZ) group (DC group) after operation [(103. 89 ± 9. 01)μmol/ L vs. (71. 52 ± 7. 03) μmol/ L, P = 0. 000]. The creatinine clearance rate ( Ccr) was also significantly decreased in DC group after operation[(1. 49 ± 0. 33)ml/ min vs. (2. 60 ± 0. 54)ml/ min, P =0. 001]. Especially in the diabetic kidney, the expression of caspase-3 was also significantly increased after intravenous injection HOCM compared with normal saline. And the expression of anti-apoptosis Bcl-2 protein was significantly decreased in DC group after the induction of DTZ, while the expression of promoting apoptosis protein Bax was significantly increased (0. 90 ± 0. 13 vs. 1. 50 ± 0. 16; 0. 92 ± 0. 04 vs. 0. 51 ± 0. 05, both P = 0. 000) . The activity of upstream signal molecule p-Akt and p-mTOR was significantly decreased (0. 46 ± 0. 08 vs. 0. 68 ± 0. 07, P = 0. 002; 0. 19 ± 0. 04 vs. 0. 50 ± 0. 07, P = 0. 000) . Conclusions The ionic high osmolality CM induce severe renal cells apoptosis in diabetic rats through activating the caspase-3 apoptotic pathway that may be mediated by upstream Akt/ mTOR (inhibiting p-Akt and p-mTOR expression) signal pathways.%目的：探讨肾细胞凋亡在糖尿病大鼠造影剂急性肾损害(CIAKI)发病中的作用,并研究其对 Akt/ mTOR 信号途径的影响。方法雄性 SD 大鼠24只,遵循体质量分层随机原则分为正常对照组(N 组)、正常＋造影剂组(NC 组)、糖尿病对照组(D 组)和糖尿病＋造影剂组(DC 组),每组6只。以腹腔单剂量注射链脲佐菌素建立糖尿病模型；10周后经股静脉注射60％泛影葡胺(10 ml/ kg),连续2 d,建立 CIAKI 模型24 h 后处死大鼠留取标本,测血、尿肌酐值；免疫组化法检测肾内凋亡相关蛋白 caspase-3的表达；Western Blot 定量检测肾组织内 Bcl-2、Bax 及 Akt/ mTOR 信号通路关键蛋白的表达。结果与 D 组比较,DC 组注射泛影葡胺后血肌酐显著增加[(103.89±9.01)μmol/ L 比(71.52±7.03)μmol/ L,P ＝0.000],而肌酐清除率显著降低[(1.49±0.33) ml/ min 比(2.60±0.54)ml/ min,P ＝0.001]；肾内凋亡相关蛋白 caspase-3阳性表达量显著增加(17.55±0.86比10.02±1.48,P ＝0.000)；抗凋亡 Bcl-2蛋白表达则显著下降,而促凋亡 Bax 蛋白表达显著增加(0.90±0.13比1.50±0.16；0.92±0.04比0.51±0.05,均为 P ＝0.000)。糖尿病 CIAKI 时上游p-Akt和 p-mTOR 均表达下调(0.46±0.08比0.68±0.07,P ＝0.002；0.19±0.04比0.50±0.07,P ＝0.000)。结论离子型高渗造影剂可能通过抑制糖尿病大鼠 Akt/ mTOR 信号通路磷酸化激活介导肾细胞经线粒体 caspase-3途径凋亡而导致急性肾损伤。
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