[Establishment of a canine slow transit constipation model and evalution of defecation, gastrointestinal transit and pathological sections].

Objective: To establish a canine model of slow transit constipation (STC), and to test the changes in defecation, gastrointestinal transit time and pathology sections. Methods: Baseline information was measured in 8 beagle dogs, and these dogs were randomly divided into the control group and the model group. The dogs in model group were given a diet of canned meat, as well as a combination of compound diphenoxylate and alosetron hydrochloride for 5 weeks. Dogs in control group were given normal diet with no special intervention. Stool frequency and consistency were observed and recorded daily, and the gastrointestinal transit time (GITT) were measured every week. All animals underwent the midline laparotomy and the colonic tissues were taken from the rectosigmoid colon, then investigated by light microscopy, electron microscopy, and immunohistochemistry to evaluate changes of protein gene product 9.5(PGP9.5), synaptophysin and c-kit between two groups. Results: 8 beagle dogs underwent all experiment items successfully.Both of the stool frequency and scores of stool consistency decreased in model group(F=6.568, P=0.043; F=25.954, P=0.002). GITT delayed in model group(F=42.573, P=0.001). After 5 weeks of intervention, in the model group, the myenteric neurons and interstitial cells of Cajal showed damage such as swelling of mitochondria under electron microscopy, and both of the PGP9.5 and synaptophysin integrated option density of rectosigmoid colon were decreased (t=3.471, P=0.013; t=2.506, P=0.046)under immunohistochemistry. The c-kit integrated option density showed no statistically significant differences between two groups(t=1.709, P=0.138). Conclusions: The canine model of STC which was consistent with clinical symptoms and pathological changes was successfully established, and it can be used to observe and evaluate the therapeutic effect of electrical stimulation, surgery and so on.目的： 建立慢传输型便秘(STC)犬模型，并检测其排便、胃肠传输及结肠组织病理学改变情况。 方法： 观察和记录8只比格犬的基线信息，将犬随机分为对照组和造模组，造模组给予肉制罐头饮食联合口服复方地芬诺酯、盐酸阿洛司琼共计5周，监测2组犬的排便次数、大便性状，测定胃肠传输时间(GITT)并进行比较。开腹手术取直乙交界处的全层结肠组织，通过光镜、透射电镜进行组织学观察；通过免疫组织化学染色检测2组犬结肠神经组织标志物蛋白基因产物9.5(PGP9.5)、突触素、Cajal间质细胞(ICC)标志物c－kit的表达水平并进行比较。 结果： 8只犬均顺利完成所有实验项目，造模干预后，造模组大便干硬明显，排便频率、大便性状得分均较对照组下降(F＝6.568, P＝0.043; F＝25.954, P＝0.002)；造模组GITT较对照组延长(F＝42.573, P＝0.001)。电镜下可见造模组肌间神经丛神经元和Cajal间质细胞出现核周间隙增大、线粒体肿胀、内质网扩张等损伤。免疫组化示造模组结肠组织PGP9.5、突触素累计光密度值较对照组降低(t＝3.471, P＝0.013; t＝2.506, P＝0.046), c－kit累计光密度值2组间差异无统计学意义(t＝1.709, P＝0.138)。 结论： 成功建立了符合临床表现及病理学变化特点的STC犬模型，该模型可用于电刺激、外科手术等复杂操作的疗效观察和评价。.