Male-specific colon motility dysfunction in the TashT mouse line.
BACKGROUND
In Hirschsprung disease (HSCR), the absence of myenteric neural ganglia in the distal bowel prevents motility and thereby causes functional intestinal obstruction. Although surgical resection of the aganglionic segment allows HSCR children to survive this condition, a number of patients still suffer from impaired motility despite having myenteric ganglia in their postoperative distal bowel. Such phenomenon is also observed in patients suffering from other enteric neuropathies and, in both cases, colonic dysmotility is believed to result from abnormalities of myenteric ganglia and/or associated interstitial cells of Cajal (ICC). To better understand this, we used a recently described HSCR mouse model called TashT.


METHODS
Intestinal motility parameters were assessed and correlated with extent of aganglionosis and with neuronal density in ganglionated regions. The neural composition of the myenteric plexus and the status of ICC networks was also evaluated using immunofluorescence.


RESULTS
TashT(Tg/Tg) mice display a strong male bias in the severity of both colonic aganglionosis and hypoganglionosis, which are associated with male-specific reduced colonic motility. TashT(Tg/Tg) male mice also exhibit a specific increase in nNos(+) neurons that is restricted to the most distal ganglionated regions. In contrast, Calretinin(+) myenteric neurons, Sox10(+) myenteric glial cells, and cKit(+) ICC are not affected in TashT(Tg/Tg) mice.


CONCLUSIONS
Male-specific impairment of colonic motility in TashT(Tg/Tg) mice is associated with both severe hypoganglionosis and myenteric neuronal imbalance. Considering these parameters in the clinic might be important for the management of postoperative HSCR patients.
Molecular Genetics of Development Laboratory, Department of Biological Sciences and BioMed Research Center, Faculty of Sciences, University of Quebec at Montreal (UQAM), Montreal, Canada.
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AM
Touré
Molecular Genetics of Development Laboratory, Department of Biological Sciences and BioMed Research Center, Faculty of Sciences, University of Quebec at Montreal (UQAM), Montreal, Canada.
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B
Charrier
Molecular Genetics of Development Laboratory, Department of Biological Sciences and BioMed Research Center, Faculty of Sciences, University of Quebec at Montreal (UQAM), Montreal, Canada. pilon.nicolas@uqam.ca.
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Pilon
D000818:Animals; D003106:Colon / Q000503:physiopathology*; D005260:Female; D005769:Gastrointestinal Motility / Q000502:physiology*; D006627:Hirschsprung Disease / Q000235:genetics* / Q000503:physiopathology*; D056885:Interstitial Cells of Cajal / Q000502:physiology; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009197:Myenteric Plexus / Q000503:physiopathology
Hirschsprung disease; chronic constipation; enteric nervous system; myenteric plexus