内皮型一氧化氮合酶在大鼠糖尿病膀胱病变中的作用

目的 探讨大鼠糖尿病膀胱病变组织中内皮型一氧化氮合酶(eNOS)的表达及意义.方法 雄性SD大鼠36只.随机分为正常组、多尿组和糖尿病组,每组12只.采用尿动力学方法对大鼠膀胱容量、单次排尿量、膀胱内最大压力、残尿壁和排尿率等指标进行评价,应用RT-PCR和蛋白质印迹方法检测大鼠膀胱组织中eNOS mRNA和蛋白质的表达水平,统计学分析其与膀胱功能的相关性.结果 6周时正常组大鼠最大膀胱容量、单次排尿量、残余尿量分别为(0.75±0.04)、(0.70±0.02)和(0.06±0.00)ml,多尿组分别为(1.62±0.15)、(1.52±0.30)和(0.11±0.01)ml,糖尿病组分别为(2.29±0.16)、(2.06±0.25)和(0.23±0.01)ml,与正常组和多尿组相比,差异具有统计学意义(P＜0.01);12周时正常组上述指标分别为(0.86±0.06)、(0.80±0.04)和(0.07±0.00)ml,多尿组分别为(1.93±0.10)、(1.77±0.11)和(0.13±0.02)ml,糖尿病组分别为(2.65±0.26)、(2.09±0.21)和(0.56±0.06)ml,各组间差异具有统计学意义(P＜0.01).糖尿病组与6周时相比,各指标增加,其中残余尿量差异具有统计学意义(P＜0.01).6周时3组排尿率分别为(93.3±2.1)%、(93.2±2.7)%和(90.0±2.5)%,组间差异无统计学意义(P＞0.05);12周时分别为(93.1±2.2)%、(93.8±3.2)%和(78.1±2.6)%,糖尿病组小于其他2组(P＜0.05).各组膀胱内压力差异无统计学意义.糖尿病组膀胱压力曲线出现压力小波动,曲线不规则.6周时各组膀胱组织中eNOSmRNA表达相对灰度值分别为0.81±0.12、0.90±0.12和1.98±0.16,糖尿病组高于其他2组,差异具有统计学意义(P＜0.01);12周时为0.87±0.17、1.05±0.11和2.89±0.23,糖尿病组与6周时相比增加(P＜0.01).6周时各组eNOS蛋白表达相对灰度值分别为0.98±0.12、0.93±0.14和2.28±0.16,糖尿病组高于其他2组(P＜0.01);12周时为1.03±0.13、1.14±0.11和3.12±0.20,糖尿病组与6周时相比增加(P＜0.01).糖尿病组大鼠膀胱eNOS蛋白表达强度与排尿率旱负相关(r=-0.669,P＜0.01).结论 膀胱组织中eNOS mRNA和蛋白表达上调可能参与了糖尿病膀胱病变的发生发展.

Role of endothelial nitric oxide synthase in the pathogenesis and development of diabetic cystopathy in STZ-induced diabetic rat model

Objective To investigate the role of endothelial nitric oxide synthase(eNOS)in the pathogenesis and development of diabetic cystopathy.Methods Diabetic model was established by a single intra-peritoneal injection of 60 mg/kg STZ in male Sprague-Dawley rats.Thirty-six rats were randomly divided into 3 groups:normal control,diuresis control and diabetes groups each(n=12).Examinations were performed at 6W and 12W after injection of STZ.Cystometry was taken to evaluate the bladder function.Expression levels of eNOS mRNA and protein were assessed with RT-PCR and Western blot assays respectively and their correlations with bladder function index were analyzed.Results The bladder capacity,single voiding volume and post-voiding volume at 6W were(0.75±0.04),(0.70±0.02)and(0.06±0.00)ml in normal group,(1.62±0.15),(1.52±0.30)and (0.11±0.01)ml in diuresis group,and(2.29±0.16),(2.06±0.25)and(0.23±0.01)ml in diabetic group.Compared with normal and diuresis groups,they were significantly increased in diabetic group(P＜0.01).At 12W,they were(0.86±0.06),(0.80±0.04)and(0.07±0.00)ml in normal group,(1.93±0.10),(1.77±0.11)and(0.13±0.02)ml in diuresis group,and(2.65±0.26),(2.09±0.21)and(0.56±0.06)ml in diabetic group.Post-voiding volume increased significantly compared with that at 6W in diabetic group(P＜0.01).At 6W,voiding efficiencies of each group were(93.3±2.1)%,(93.2±2.7)%and(90.0±2.5)0A,with no significant difference.While at 12W they were(93.1±2.2),(93.8±3.2)and(78.1±2.6)%.Voiding efficiency was significantly reduced in diabetic group compared with other 2 groups.No significant difference was observed among bladder pressures of each group.Expression levels of eNOS mRNA from each group at 6W were 0.81±0.12,0.90±0.12,and 1.98±0.16.Compared with normal and diuresis groups,eNOS mRNA expression level significantly increased in diabetic group(P＜0.01).while at 12W they were 0.87±0.17,1.05±0.11,and 2.89±0.23 respectively.Compared with that at 6W,expression level of eNOS mRNA significantly increased at 12W in diabetic group(P＜0.01).Expression levels of eNOS protein were 0.98±0.12,0.93±0.14,and 2.28±0.16.eNOS protein expression level significantly increased in diabetic group,compared with normal and diuresis groups(P＜0.01).At 12 W they were 1.03±0.13,1.14±0.11,and 3.12±0.20,respectively.Compared with that at 6W,expression level of eNOS protein significantly increased at 12W in diabetic group(P＜0.01).The expression level of eNOS mRNA was negatively correlated with voiding efficiency in diabetic group(r=-0.669,P＜0.01).Conclusion The up-regulated expression levels of both eNOS mRNA and protein may participate in the pathogenesis and development of diabetic cystopathy.