膀胱出口梗阻后大鼠逼尿肌细胞内质网形态及GRP78表达的研究

目的观察膀胱出口部分梗阻后膀胱重构中,逼尿肌平滑肌细胞内质网形态及内质网应激标志性蛋白——葡萄糖调节蛋白78(GRP78)的表达情况,探讨内质网应激在膀胱重构机制中可能的作用。方法雄性Wistar大鼠40只,随机分为假手术组10只,梗阻2周组15只,梗阻4周组15只,采用经会阴途径球部尿道部分结扎的方法建立膀胱出口部分梗阻模型。采用透射电子显微镜观察逼尿肌平滑肌细胞的超微结构,通过免疫组化和Real-time PCR分别检测逼尿肌中GRP78蛋白及mRNA表达变化。结果假手术组、梗阻2周组和梗阻4周组大鼠膀胱逼尿肌细胞GRP78蛋白阳性表达率分别为(3.37±0.38)%、(51.22±0.27)%、(27.02±1.85)%,梗阻2周组大鼠膀胱逼尿肌中GRP78阳性表达明显增多,与假手术组相比有明显差异(P0.01),梗阻4周组大鼠逼尿肌中GRP78阳性表达增多,与假手术组相比有明显差异(P0.01),但比梗阻2周组表达量减少(P0.01)。各组GRP78mRNA表达量分别为(22.21±1.58)、(30.62±2.49)、(24.52±2.24),梗阻2周组大鼠膀胱逼尿肌细胞GRP78mRNA表达较假手术组明显增加(P0.01);与梗阻2周组相比,梗阻4周组大鼠膀胱逼尿肌细胞GRP78mRNA表达量下降,有显著性统计学意义(P0.01),梗阻4周组与假手术组相比无统计学意义。结论在梗阻后膀胱重构过程中,逼尿肌平滑肌细胞内质网形态有明显损伤性变化,GRP78蛋白及mRNA表达水平明显增加,提示内质网应激参与膀胱重构的进展。

Micromorphology of endoplasmic reticulum and GRP78 expression in bladder de- trusor reconstruction of male rat model of partial bladder outlet obstruction

Objective To observe the micromorphology of bladder detrusor and the expression of biomarker of endoplas- mic reticulum stress （glucose-regulated protein 78, GRP78） in bladder reconstruction of male rat model of partial bladder outlet obstruction, to explore the role of endoplasmic reticulum stress in bladder reconstruction. Methods A total of 40 male Wistar rats were divided into control group （sham group, n 10）, 2-week obstruction group （n =15） and 4-week obstruction group （n = 15）. The microstructrue of bladder detrusor smooth cells was observed with transmission electron microscope. The expres- sion of protein and mRNA of GRP78 were detected with immunohistochemical and real-time PCR methods. Results The ex- pression of GRP78 protein was （3.37＋_0.38） ~, （51.22±0.27） % and （27.02± 1.85） % in sham-operated group, 2- week and 4-week group, respectively. There was significant difference between 2-week and 4- week group （P〈0.01）. The difference between sham-operated group and obstruction groups was significant （P〈O. The expression of GRP78 mRNA was （22.21 ± 1.58）, （30.62±2.49）, （24.52±2.24） in sham-operated group, 2- week and 4-week group, respectively. There was signifi- cant difference between sham-operated group and 2-week group （P〈0.01）. The difference between 2-week group and 4-week group was significant （P〈0.01）. Conclusions In the process of bladder reconstruction after partial bladder outlet obstruc- tion, there is an evident change in the morphology of bladder detrusor cells endoplasmic reticulum, and expression of protein and mRNA of GRP78. This suggests that endoplasmic reticulum stress plays a role in the process of bladder reconstruction.