Comparative analysis of c-kit gene expression and c-Kit immunoreactivity in horses with and without obstructive intestinal disease

Previous immunohistochemical studies targeting the receptor tyrosine kinase (c-Kit) have demonstrated an apparent reduction in the number of gastrointestinal pacemaker cells--the interstitial cells of Cajal (ICC)--in horses with intestinal motility disorders. This study compared the level of transcription of the c-kit gene encoding this receptor in horses with and without such motility disorders. Transcription levels of this gene were also compared to the density of ICC immunohistochemically positive for the c-Kit antigen. Intestinal samples were collected from 18 horses with intestinal disease and from 15 control animals. Following gene extraction and identification, real-time quantitative analysis of c-kit and a control gene, ACTB (β-actin), was carried out on all samples and the density of the c-Kit-positive ICC compared. There was a significant reduction in c-Kit immunoreactivity in the ICC of horses with large intestinal obstructive disorders relative to controls but no significant difference in the transcription of the c-kit gene between normal and affected animals. Further studies will be required to elucidate the mechanisms regulating c-Kit expression and to assess the pathophysiological significance of these findings.