Roux—en—Y胃旁路术对2型糖尿病大鼠肾功能的影响

Effects of Roux-en-Y gastric bypass on the renal function of rats with type 2 diabetes mellitus

目的探讨Roux—en—Y胃旁路术对2型糖尿病大鼠肾功能的影响。方法采用高脂高糖饮食联合腹腔注射小剂量链脲佐菌素（streptozocin，STZ，35肛∥g）方法建立2型糖尿病大鼠模型。将造模成功的糖尿病SD大鼠分为3组：糖尿病组（8只），假手术组（8只），手术组（14只）；另取正常SD大鼠作为正常组（8只）。术前、术后8周检测大鼠空腹血糖，术前及术后4、8周测定血清BUN、Cr；术后8周取肾组织进行病理组织学观察，计算肾脏质量指数；免疫组织化学染色方法检测肾组织纤连蛋白、Ⅳ型胶原和TGF—B1的表达，采用Real—timePCR和Westernblot检测MMP-2、MMP-9mRNA和蛋白的表达。多组比较采用单因素方差分析，两两比较采用LSD检验。结果术后8周，糖尿病组大鼠血糖、BUN、Cr、肾脏质量指数分别为（15．9±1．6）mmol／L、（9．24-0．6）mmol／L、（44±4）~mol／L、（10．7±1．5）mg／g，手术组大鼠分别为（5．9±0．7）mmol／L、（6．64-0．4）mmol／L、（304-2）~mol／L、（8．6±0．6）mg／g，两组比较，差异有统计学意义（P〈0．05）。与正常组比较，糖尿病组、假手术组大鼠肾小球体积增大，系膜增生；手术组有明显改善。正常组大鼠肾脏皮质纤连蛋白、Ⅳ型胶原、TGF—B1免疫组织化学染色积分光密度值、MMP-2、MMP-9mRNA和蛋白的表达水平分别为664±23、864-5、524-6、1．00-4-0．04、644-4、1．004-0．20、48±5，糖尿病组大鼠分别为16654-44、7894-66、4594-35、0．52±0．13、514-6、0．364-0．05、384-4，假手术组大鼠分别为1701±55、7544-49、4254-42、0．544-0．19、484-5、0．434-0．09、394-4，手术组大鼠分别为11054-61、1954-11、1474-16、1．53±0．29、634-5、1．114-0．14、49-4-5，4组比较，差异均有统计学意义（F=1340．30，4982．50，2025．10，654．19，13．58，610．74，7．86，P〈0．05）。两两比较，差异均有统计学意义（P〈0．05）。结论Roux—eFl—Y胃旁路术可改善糖尿病大鼠肾功能，减少细胞外基质沉积，其作用机制可能与抑制TGF-β1表达和上调MMP-2、MMP-9mRNA和蛋白水平有关。

Objective To investigate the effects of Roux-en-Y gastric bypass on the renal function of rats with type 2 diabetes mellitus. Methods Rat models of type 2 diabetes mellitus were established by intraperitoneal injection of streptozotocin （35 p^g/g） and a high-fat diet. All the rats were randomly divided into diabetes group （8 rats） , sham operation group （8 rats） and Roux-en-Y gastric bypass group （ 14 rats）. Another 8 normal rats were selected in the normal control group. The level of fasting blood glucose was detected preoperatively and 8 weeks after the operation. The levels of blood urea nitrogen and creatinine were detected preoperatively and 4 and 8 weeks after the operation. Pathological changes of the renal tissue were observed and the indexes of kidney hyper- trophy were analyzed 8 weeks after the operation. The expressions of fibronectin, type iV collagen and TGF-~I were detected by immunohistochemieal staining. The mRNA and protein expressions of MMP-2 and MMP-9 were detected by Real-time PCR and Western blot, respectively. All data were analyzed using the analysis of variance or LSD test. Results In postoperative week 8, the levels of fasting glucose, blood urea nitrogen, creatinine and index of kidney hypertrophy were （15. 9 _＋ 1. 6） retool/L, （9. 2 _＋ 0. 6） retool/L, （44 ＋4） p.moL/L and （10.7 _＋ 1.5）mg/g in the diabetes group, and （5.9 _＋0.7） mmoL/L, （6.6 -＋0.4） mmol/L, （30 -＋2） p, mol/L and （ 8.6 -＋ 0.6） mg/g in the Roux-en-Y gastric bypass group, with significant difference between the 2 groups （ P 〈 0.05）. Compared with the normal control group, the volumes of glomerulus of kidney in the diabetes group and the sham operation group were greater, and mesangial proliferation was detected. The integral optical density of fibronectin, type 1V collagen, TGF-131, the mRNA and protein expressions of MMP-2 and MMP-9 were 664 ~ 23, 86 ＋ 5, 52 ＋ 6, 1. O0 -＋ 0.04, 64 _＋ 4, 1.00 ＋ 0.20, 48 ~ 5 in the normal control group, and 1665 ＋ 44, 789 -＋ 66, 459 ---35, 0.52 -＋0.13,51 -＋6, 0.36 ＋0.05, 38 -＋4 in the diabetes group, and 1701 -＋55,754 -＋49,425 -＋ 42, 0.54 ＋ 0.19, 48 -＋ 5, 0.43 -＋ 0.09, 39 ＋ 4 in the sham operation group, and 1105 -＋ 61, 195 -＋ 11, 147 ~ 16, 1.53 -＋ 0.29, 63 -＋ 5, 1. 11 -＋ 0. 14, 49 -＋ 5 in the Roux-en-Y gast,＇ic bypass group, with significant difference between the 4 groups （F= 1340. 30, 4982. 50, 2025. 10, 654. 19, 13.58, 610. 74, 7. 86, P 〈0.05）. Significant difference was detected in pairwise comparison （P 〈 0.05 ）. Conclusion Roux-en-Y gastric bypass surgery can improve the renal function of rats with type 2 diabetes mellitus, reduce deposition of extracellular matrix. Its mech- anism may be related to inhibition of TGF-131 expression and increase of MMP-2 and MMP-9 mRNA and protein expressions.