RESUMO
Objective:To establish a rat model of experimental aganglionosis for MSCs transplantation,and to observe its biological features in rat.Methods:Ninety Sprague Dawley rats,8～9 weeks old,were randomly divided into two groups:treatment group(n45) and control group(n45).All animals were operated upon under Ketamine anesthesia.In treatment group,0.1% benzalkonium chloride (BAC) was applied onto the serosa for 40 minutes,and then the colon was washed well with 0.9% normal saline.For the control group,0.9% saline was applied using the same method in treatment group.Macroscopic and microscopic observations,contrast roentgenogrphy of colon,colon manometry,pharmacologic examinations for contraction of colonic smooth muscle and the expression of AchE,nestin,Chrm3 by RT-PCR were performed at an interval of 1week,2weeks,3weeks,4weeks and 8weeks after operation.Results:1 week after BAC treatment,the rats had abdominal distention.Roentgenographic examination and autopsy revealed a narrowed segment accompanied by distended proximal colon filled with massive feces,and the longer the duration after treatment,the more serious the distention.Manometry showed the abolition of reflex contraction in colonic smooth muscle,and pharmacologic examinations indicated supersensitivity to acetylcholine. Histologic examinations revealed transparent reduction and vacuolation of ganglion cells 1 week after BAC treatment with complete disappearence of 3 weeks after BAC treatment.Conclusion:The animal model for experimental aganglionosis is successfully established by applying 0.1%BAC onto the serosa of descending colon,which provides an experimental basis for the future MSCs transplantation and differentiation into neuronal cells in rat colon.