组织蛋白酶B和胱抑素C在糖尿病肾病大鼠肾组织中的表达及意义

目的： 观察糖尿病大鼠肾组织中组织蛋白酶B(CB)和胱抑素C(CC)的表达并探讨其在糖尿病肾病中的可能作用。方法: 将Wistar大鼠分成健康对照组(C组,n=30)和糖尿病组(M组,n=35)，糖尿病组给予STZ 55 mg/kg腹腔内注射，72 h后随机血糖>16.7 mmol/L为造模成功。分别在第4、8、16周各处死10只，在处死前留取24 h尿量测24 h尿白蛋白，留取血清标本测血肌酐，留取肾脏标本做免疫组化和实时荧光定量PCR测CC、CB、Ⅳ型胶原(colⅣ)、纤维连接蛋白(FN)的表达情况。结果: C组的各项指标各时点均未见到有显著变化，与第4周相比，第8周M组大鼠内生肌酐清除率(Ccr)和24 h尿白蛋白显著升高(P<0.01)，免疫组化和PCR结果显示CB、CC、colⅣ、FN在第8周出现明显上调(P<0.01或P<0.05)，CB在16周下调(P<0.01),而CC显著上调(P<0.01)。相关分析显示CB的表达与24 h尿蛋白、colⅣ、FN蛋白表达和mRNA表达呈负相关（P<0.01）。结论: 糖尿病大鼠肾组织存在CB和CC平衡的失调，这可能是引起糖尿病肾病细胞外基质沉积的原因之一。

Expression of cathepsin B and cystatin C and its potential role in diabetic rats

AIM: To observe the expressions of cathepsin B (CB) and cystatin C (CC) in different stage of diabetic rats and to investigates their potential roles.METHODS: Sixty rats were divided into diabetes mellitus group induced by intravenous injection of streptozotocin (55 mg/kg) and normal group injected with citrate buffer. Ten rats were sacrificed respectively at the end of fourth week, eighth week and sixteenth week in both groups. 24 h urine excretion was collected in rats before sacrifice. The blood and the kidney were also collected. The mRNA and protein expressions of CB and CC in kidney were detected by real time PCR and immunohistochemical staining, respectively.RESULTS: At the end of eighth week, the expression of Ccr, 24 h urinary protein excretion, CB, CC in diabetic rats increased significantly, compared to the results at the fourth week (P<0.01 or P<0.05). With the aggravation of diabetic nephropathy, the expressions of CC, colⅣ, FN and 24 h urinary protein excretion were up-regulated significantly (P<0.01 or P<0.05). The expression of CB in diabetic rats was up-regulated at eighth week significantly (P<0.01), whereas, at the end of sixteenth week it was down-regulated significantly (P<0.01). The 24 h urinary protein excretion, the expressions of colⅣ at protein and mRNA levels and FN were negatively correlated with CB (P<0.01).CONCLUSION: The unbalance of CB and CC exists in diabetic nephropathy renal tissue, which is likely to lead to the accumulation of extracellular matrix.