Distribution of interstitial cells of Cajal in Meriones unguiculatus and alterations in the development of incomplete intestinal obstruction.

The interstitial cells of Cajal (ICCs) act as pacemaker cells that are involved in gastrointestinal (GI) motility disorders, although the pathogenesis of these disorders is still unclear. The GI tract of Mongolian gerbils shares similar anatomical features with that of humans, but no investigation of ICCs has been reported in the GI tracts of this animal. In the present study, we first observed the distribution and morphological features of ICCs in the Mongolian gerbil GI tract. The ICCs were mainly distributed within the smooth muscle layers (ICC-IM), the myenteric plexus (ICC-MY), the deep muscular plexus in the small intestine (ICC-DMP) and the submucosal surface of the circular muscle layer in the colon (ICC-SM). The density of the ICC-IM gradually decreased from the stomach to the colon, whereas the density of the ICC-MY gradually increased. Second, we compared differences in the ICCs between the control and obstructed intestines, and no significant difference was observed in the number of ICCs after 7 days of obstruction. However, the numbers were reduced by approximately day 14 of obstruction. The pattern of immunoreactivity also partly differed from that of the control group, i.e., a scattered and interrupted network of ICCs was often observed. Western blotting revealed that p-Kit and SCF were significantly reduced in the dilated intestines by day 14. Our results indicate that the Mongolian gerbil may be a good animal model for studying changes in ICCs that may contribute to the pathogenesis of GI motility disorders.