环磷酰胺腹腔注射诱导建立大鼠间质性膀胱炎模型的优化

Optimization of establishment of a rat model of cyclophosphamide-induced interstitial cystitis

目的探索环磷酰胺腹腔注射建立大鼠间质性膀胱炎模型的理想剂量。方法大鼠随机分七组,腹腔注射生理盐水作为对照或50 mg/kg、100 mg/kg、150 mg/kg、200 mg/kg、250 mg/kg和300 mg/kg环磷酰胺诱导建立间质性膀胱炎模型。用HE染色和Real-time PCR方法从组织学和分子水平评估不同剂量环磷酰胺对膀胱组织的致炎效果,采用尿动力学测定、行为量表和Von-Frey测试进行膀胱功能及感觉评定,综合评价各组大鼠建模情况。结果50 mg/kg组大鼠膀胱炎症指标和自发性痛觉过敏评分较对照组均无显著性差异。100 mg/kg组大鼠膀胱部分炎症指标较对照组显著增高(P<0.05),但自发性痛觉过敏与对照组无明显差异;150 mg/kg和200 mg/kg大鼠膀胱炎症指标较对照组明显增高(P<0.05),且出现自发性疼痛过敏(P<0.05),其中200 mg/kg组观察到大鼠在CYP注射后48 h内死亡;250 mg/kg和300 mg/kg组大鼠虽然膀胱炎症指标和自发性痛阈值均较对照组明显增高(P<0.05),但膀胱收缩力受损(P<0.05)且观察到大鼠在环磷酰胺注射后48 h内死亡。结论环磷酰胺(150 mg/kg)腹腔注射是一种建立大鼠间质性膀胱炎模型的理想方法,可同步模拟间质性膀胱炎的两大特征:膀胱炎症和自发疼痛,且兼顾了建模效率和大鼠存活率。

Objective To explore the establishment of a rat model of interstitial cystitis based on intraperitoneal injection of cyclophosphamide.Methods Saline or gradient concentrations of cyclophosphamide were intraperitoneally injected in rats to establish an animal model of interstitial cystitis.The grade of bladder inflammation was then estimated at the histological and molecular levels based on hematoxylin-eosin staining and real-time polymerase chain reaction.The rats’pain sensation was tested by both behavior recording and Von Frey examination.Mortality during the study was also recorded.Results The bladder inflammatory indices and pain sensitivity of the rats in the 150-,200-,250-,and 300-mg cyclophosphamide groups were significantly higher than those of the control rats.Urodynamic examination revealed impaired contraction capacity of the rats’bladders in the 250-and 300-mg cyclophosphamide groups.Rats in the 100-mg cyclophosphamide group showed observable inflammatory changes in their bladders without a significant increase in sensitivity to spontaneous visceral pain or somatic nociception.The rats in the 50-mg cyclophosphamide group showed no alteration of bladder inflammatory indices or pain sensitivity.Some rats died within 48 hours after cyclophosphamide injection in the 200-,250-,and 300-mg groups.Conclusions Intraperitoneal injection of cyclophosphamide is a feasible and reliable method for the establishment of a rat model of interstitial cystitis,showing the two critical features of this disease:bladder inflammation and pain sensation.Based on our data,we recommend 150 mg/kg as a suitable dose for the establishment of a rat model of interstitial cystitis.