慢性避水应激法建立大鼠肠易激综合征模型及其评价

Establishment of irritable bowel syndrome model in rats by chronic water avoidance stress method and its evaluation

目的:探讨慢性避水应激(WAS)法建立肠易激综合征(IBS)大鼠模型的方法,并评价其可行性。方法:30只雄性清洁型Wistar大鼠,随机分为对照组(n=10)和模型组(n=20),模型组大鼠每日采用WAS法诱导1 h,连续干预造模10 d;对照组大鼠不进行任何干预。造模结束后,观察并记录2组大鼠一般情况和体质量,采用高架十字迷宫(EPM)实验检测2组大鼠进入开放臂次数(OE)百分率和进入开放臂时间(OT)百分率,腹壁撤回反射(AWR)实验检测2组大鼠内脏敏感性,心电图检查2组大鼠心率变异性(HRV),腹外斜肌肌电图(EMG)检测2组大鼠结直肠痛敏阈值,多通道生理信号记录仪检测2组大鼠结肠慢波频率。结果:2组大鼠在整个造模期间均无死亡情况,造模结束后,模型组大鼠均伴有精神状态欠佳、自主活动减少、少动、皮毛散乱且无光泽、易激惹和肛门口不净等情况;对照组大鼠精神状态、自主活动、皮毛和肛周无明显变化。与对照组比较,模型组大鼠体质量明显降低(P<0.05)。EPM实验,与对照组比较,模型组大鼠OE百分率和OT百分率均明显降低(P<0.01)。AWR实验,模型组中AWR半定量评分≥3分大鼠共12只,内脏痛大鼠模型造模成功率为60%。与对照组比较,模型组大鼠低频信号(LF)和LF/高频信号(HF)比值均明显升高(P<0.01),HF明显降低(P<0.05)。EMG法,与对照组比较,模型组大鼠结肠痛敏阈值明显降低(P<0.01),结肠慢波频率明显升高(P<0.01)。结论:采用WAS法建立IBS大鼠模型,大鼠行为及精神情绪改变、内脏敏感性升高、结肠慢波频率加快和自主神经系统平衡性紊乱,WAS法可作为一种有效的造模方式,用于观察和评价IBS治疗的相关药物及干预方法。

Objective:To discuss the method for establishing the rat models of irritable bowel syndrome(IBS) by chronic water avoidance stress(WAS) method,and to evaluate its feasibility.Methods:Thirty male Wistar rats were randomly divided into control group(n=10) and model group(n=20).The rats in model group were induced by WAS method for 1 h everyday,lasting for 10 consecutive days;the rats in control group underwent no interventions.After modeling,the general conditions and body weights of the rats in two groups were observed and recorded.The elevated plus maze(EPM) test was used to detect the percentages of the number of open arm entries(OE) and the time spent in open arms(OT) of the rats in two groups;the abdominal withdrawal reflex(AWR) test was used to assess the visceral sensitivity of the rats in two groups;electrocardiography was used to detect the heart rate variability(HRV) of the rats in two groups;electromyography(EMG) of the external oblique muscle was used to detect the colorectal pain sensitivity thresholds of the rats in two groups;multi-channel physiological signal recorder was used to monitor the slow wave frequency of the colon of the rats in two groups.Results:There were no death rats in both groups during the modeling period.After modeling,the rats in model group exhibited poor mental status,reduced spontaneous activity,hypoactivity,disordered and dull fur,irritability,and unclean anal areas;whereas,the rats in control group showed no significant changes in the mental state,spontaneous activity,fur,and perianal area.Compared with control group,the body weight of the rats in model group was significantly decreased(P<0.05).The EPM test results showed that compared with control group,the OE percentage and OT percentage of the rats in model group were significantly decreased(P<0.01).The AWR test results showed that 12 rats in model group scored ≥3 points,indicating that the successful rate in creating the visceral pain models was 60%.Compared with control group,the low frequency(LF) signals and the ratio of LF/high frequency(HF) of the rats in model group were significantly increased(P<0.01),and the HF was significantly decreased(P<0.05).The EMG results showed that compared with control group,the coloretal pain sensitivity threshold of the colon of the rats in model group was significantly decreased(P<0.01),and the slow wave frequency of the colon was significantly increased(P<0.01).Conclusion:The WAS method for establishing the rat model of IBS effectively demonstrates the changes in behavior and mental state,increased the visceral sensitivity,accelerated colonic slow wave frequency,and autonomic nervous system imbalance;the WAS method can serve as an effective modeling approach for observing and evaluating the related drugs and interventions on treatment of IBS.