大豆异黄酮对糖尿病模型大鼠肾组织nephrin蛋白表达的影响

Effect of soybean isoflavone on expression of nephrin in kidney tissue of diabetic model rats

目的观察大豆异黄酮(SI)对糖尿病大鼠肾组织nephrin表达的影响,探讨其对糖尿病肾病治疗作用的机制。方法健康SD大鼠一次性尾静脉注射链佐星60 mg·kg-1制备糖尿病大鼠模型,72 h后分别ig给予SI 40,120和360 mg·kg-1,每天1次,连续8周。8周后,血糖仪检测空腹血糖(FBG)水平;ELISA法检测24 h尿蛋白(UP);全自动生化分析仪检测血肌酐(SCr)、尿素氮(BUN)、丙二醛(MDA)和超氧化物歧化酶(SOD)含量;Western蛋白质印迹法检测肾组织nephrin、肿瘤坏死因子α(TNF-α)及NF-κB蛋白表达。结果与正常对照组相比,糖尿病模型对照组FBG,24 h UP,BUN,SCr及MDA均明显升高(P<0.05,P<0.01),SOD水平明显降低(P<0.01)。与模型对照组相比,SI 40,120和360 mg·kg-1组BUN水平明显降低(P<0.05,P<0.01),由(24.3±6.3)mmol·L-1分别降至16.8±4.9,13.4±5.4和(7.7±1.2)mmo·lL-1;SI 360 mg·kg-1组24 h UP由(1.26±0.45)mg显著降低至(0.88±0.15)mg(P<0.01),SCr由(56.4±8.4)μmo·lL-1显著降低至(35.3±4.3)μmo·lL-1(P<0.01),MDA水平由(8.32±1.40)μmo·lL-1显著降低至(5.33±0.95)μmol·L-1(P<0.01);SI 120和360 mg·kg-1组SOD水平由(125.5±2.4)kU·L-1明显升高至(144.2±9.2)和(169.2±3.2)kU·L-1(P<0.01)。SI 360 mg·kg-1组与120 mg·kg-1组比较,SCr,BUN及MDA水平显著降低(P<0.05,P<0.01),SOD水平显著升高(P<0.01)。与正常对照组相比,模型组肾组织nephrin蛋白表达显著降低(P<0.01),TNF-α表达显著升高(P<0.01);与模型对照组相比,SI 40,120和360 mg·kg-1组nephrin蛋白表达明显升高(P<0.01),SI 120和360 mg·kg-1组TNF-α及NF-κB表达明显降低(P<0.01)。结论 SI治疗糖尿病肾病的作用机制可能部分与其抗炎、抗氧化及增加nephrin表达有关。

OBJECTlVE To observe the effect of soybean isoflavone（ SI）on the expression of nephrin and investigate its protection mechanism in the kidney of diabetic rats. METHODS A diabetic rat modeI was induced after streptozocin（STZ）60 mg·kg-1 was injected into Sprague-DawIey rats. After 72 h,SI 40,120 and 360 mg·kg-1 was ip given to rats in SI groups,respectiveIy,once daiIy,for 8 weeks. The concentration of fasting bIood glucose（ FBG）was determined by a bIood glucose meter. Urine protein（UP）of 24 h was determined using ELISA. The concentration of serum creatinine（SCr）,bIood urea nitrogen（BUN）,malondialdehyde（mDA）and superoxide dismutase（SOD）was determined by an automatic biochemical analyzer. The expression of nephrin,tumor necrosis factor-α（TNF-α）and NF-κB protein in renal tissue was measured by Western bIotting,respectiveIy. RESULTS Compared with normal control group,the concentration of FBG,24 h UP,BUN,SCr and mDA in modeI group was all siginificantIy increased（P﹤0.05,P﹤0.01）,but SOD was decreased（ P﹤0.01）.Compared with modeI group,BUN in SI 40,120 and 360 mg·kg-1 groups decreased from（24.3±6.3）mmol·L-1 to（16.8±4.9）, （13.4±5.4）and（7.7±1.2）mmol·L-1 ,respectiveIy,24 h UP in SI 360 mg·kg-1 group decreased from （1.26±0.45）mg to（0.88±0.15）mg（ P﹤0.01）,SCr decreased from（56.4±8.4）μmol·L-1 to（35.3± 4.3）μmol·L-1（P﹤0.01）,mDA decreased from（8.32±1.40）μmol·L-1 to（5.33±0.95）μmol·L-1（P﹤0.01）, but SOD in SI 120 and 360 mg·kg-1 groups increased from（125.5 ±2.4）kU·L-1 to 144.2 ±9.2 and （169.2±3.2）kU·L-1（P﹤0.01）. Compared with SI 120 mg·kg-1 ,SCr,BUN and mDA in SI 360 mg·kg-1 group were all siginificantIy Iower（P﹤0.05,P﹤0.01）,but SOD was higher（P﹤0.01）. Compared with normal control group,the expression of nephrin protein greatIy decreased（P﹤0.01）,whiIe the expres-sion of TNF-α protein greatIy increased in modeI group（ P ﹤0.01）. Compared with modeI group,the expression of nephrin protein greatIy increased in SI 40,120 and 360 mg·kg-1 groups（P﹤0.01）,whiIe the expression of TNF-α and NF-κB protein greatIy decreased in SI 120 and 360 mg·kg-1 groups（P﹤0.01）. CONCLUSlON The mechanism by which SI protects the kidney may be partIy reIated to anti-inflammation,antioxidation and increasing the expression of nephrin in diabetic rats.