Abnormal enteric innervation identified without histopathologic staining in aganglionic colorectum from a mouse model of Hirschsprung's disease

Abstract Purpose The piebald lethal mouse with a deletion of endothelin-B receptor gene (EDNRB) is a model for Hirschsprung's disease (HD), whereas the SOX10 gene is vital for the development of intestinal neural crest–derived cells. Recently, we created a SOX10 transgenic mouse with intestinal neural crest–derived cells visible with enhanced green fluorescent protein (VENUS), that is, SOX10-VENUS+ /EDNRBsl/sl to investigate intestinal innervation in HD. Methods SOX10-VENUS+ /EDNRBsl/sl (n = 30) were compared with wild-type littermates as controls (EDNRBs/s , n = 30). Mice were killed on days 3, 7, or 12 of age. The entire colorectum was excised, fixed with 4% paraformaldehyde, and examined using fluorescence microscopy alone without staining. Results In normoganglionic colorectum from controls, a grid network of nerve fibers/glial cells was visualized that connected smoothly with extrinsic nerve fibers running along the colorectal wall. In aganglionic colorectum from SOX10-VENUS+ /EDNRBsl/sl mice, there was no grid network and more extrinsic nerve fibers than controls that invaded the colon wall becoming elongated with branching fibers. Normoganglionic colon from controls and SOX10-VENUS+ /EDNRBsl/sl mice appeared the same. Innervation patterns did not change over time. Conclusion This is the first time for abnormal enteric innervation in aganglionic colon in a model for HD to be visualized without staining.