环磷酰胺诱导SD大鼠膀胱疼痛综合征模型的有效性

Urodynamic and histological evaluation of cyclophosphamide-induced bladder pain syndrome in SD rats

目的:用环磷酰胺腹腔注射的方法建立SD大鼠膀胱疼痛综合征模型,从尿动力学与组织学层面评估模型的有效性,为膀胱疼痛综合征的临床研究奠定动物学基础,并进一步指导临床治疗。方法:将32只8周龄SD大鼠随机分为4组,包括急性实验组、急性对照组、慢性实验组、慢性对照组,每组8只。急性实验组在第1天测完尿动力学数据后即刻行腹腔注射环磷酰胺150 mg/kg,第3天再次行尿动力学检查,之后处死大鼠,获取膀胱组织。慢性实验组第1天测量尿动力基线数据后,在第1、4、7天腹腔注射环磷酰胺75 mg/kg,第8天再次测量尿动力学数据后处死大鼠,得到膀胱组织。急性对照组与慢性对照组在腹腔注射等量生理盐水,尿动力学测量时间点与对应的实验组一致。苏木精-伊红(hematoxylin-eosin staining,HE)染色评估膀胱组织病理学改变。结果:急性与慢性每组的对照组和实验组的尿动力学基线水平差异无统计学意义。急性实验组给药后尿动力学最大膀胱容量显著减小(t=-2.961,P<0.05),组织学可看到严重的间质水肿、明显的炎性细胞浸润、黏膜水肿和黏膜下出血,部分尿路上皮缺失,符合急性膀胱炎表现。慢性实验组给药后可看到尿动力学最大膀胱容量显著减小(t=-3.886,P<0.05),膀胱顺应性较对照组降低,但差异无统计学意义,慢性实验组组织学表现为尿路上皮剥脱、间质水肿、黏膜下出血和淋巴细胞等炎性细胞浸润,血管分布密集。结论:急性实验组单次腹腔注射环磷酰胺可诱导大鼠产生膀胱疼痛综合征急性发作的膀胱炎症表现,慢性实验组反复注射环磷酰胺可诱导大鼠产生慢性膀胱疼痛综合征慢性炎症的组织学改变,但急性与慢性实验组膀胱功能并未出现明显受损。

Objective:To establish a model of bladder pain syndrome in SD rats by cyclophosphamide intraperitoneal injection,to evaluate the effectiveness of the model from the urodynamic and histological levels,to lay a zoological foundation for the clinical study of bladder pain syndrome,and to further guide clinical treatment.Methods:Thirty-two 8-week-old SD rats were randomly divided into 4 groups,including acute test group,acute control group,chronic test group,and chronic control group,with 8 rats in each group.The acute test group received intraperitoneal injection of cyclophosphamide 150 mg/kg immediately after the measurement of urodynamic data on the first day,and urodynamic examination was performed again 2 days later.After that,the rats were sacrificed to obtain bladder tissue.In the chronic test group,after measuring the baseline data of urodynamics on the first day,cyclophosphamide 75 mg/kg was intraperitoneally injected on the first,fourth,and seventh days,and the rats were sacrificed after measuring the urodynamic data again on the eighth day to obtain bladder tissue.The acute control group and the chronic control group were injected with the same amount of normal saline during intraperitoneal injection,and the urodynamic testing time point were consistent with the corresponding test groups.Histopathological changes of the bladder were assessed by HE staining.Results:In each acute and chronic group,there were no intragroup differences in baseline urodynamic levels between the test and control groups.The urodynamic maximum bladder volume was significantly reduced in the acute test group after administration(t=-2.961,P<0.05),histologically,severe interstitial edema,obvious inflammatory cell infiltration,mucosal edema and submucosal hemorrhage,and partial urothelium were absent could be seen,which were consistent with acute cystitis performance.The urodynamic maximum bladder capacity was significantly reduced in the chronic test group after administration(t=-3.886,P<0.05),and the bladder compliance was lower than that in the control group,but not significant,the histological manifestations were urothelial exfoliation,interstitial edema,submucosal hemorrhage,infiltration of inflammatory cells such as lymphocytes,and dense vascular distribution.Conclusion:In the acute test group,a single intraperitoneal injection of cyclophosphamide could induce acute bladder inflammation in the rats.In the chronic test group,repeated injections of cyclophosphamide could induce histological changes in chronic inflammation of chronic bladder pain syndrome in the rats.But the bladder function was not significantly impaired.