Anorectal neural crest derived cell behavior after the migration of vagal neural crest derived cells is surgically disrupted: implications for the etiology of Hirschsprung’s disease

Abstract

In Hirschsprung's disease (HD), thick extrinsic nerve fibers can be associated with the aganglionic segment in the anorectum. We surgically disrupted the migration of vagal neural crest cell-derived cells (vagal NCC) in embryos from transgenic mice we created previously (SOX10-VENUS Tg) which have the SOX10 gene labeled with Venus (V), a green fluorescent protein, to observe sacral NCC activity in the anorectum. Proximal colon harvested from SOX10-VENUS Tg embryos on day 10.5 (n=10) was transected at the ascending colon. V-positive sacral NCC in the anorectum were observed during organ culture under fluorescence stereoscopic microscopy, and compared with non-transected control specimens (n=10). In transected specimens, no V-positive sacral NCC were identified initially in the anorectum. By day 2, there were thick beaded sacral NCC in the anorectum in 6/10 (60%) that migrated steadily to the transected end over 3-4days. In controls, thinner and shorter V-positive sacral NCC began migrating cranially on day 2, and were met by distally migrating vagal NCC. Disruption of vagal NCC migration appears to induce sacral NCC activity in the anorectum, suggesting that thick extrinsic nerve fibers seen in HD may be a secondary phenomenon.