The development of colon innervation in trisomy 16 mice and Hirschsprungs disease

Table 1 The development of the colon and mensenteric innervation of trisomy 16 mice and their normal littermates in chronological sequence

	ED13		ED14		ED15		ED16		ED17		ED18
	N	T	N	T	N	T	N	T	N	T	N	T
PM	-	-	+	-	++	+	++	+	+++	++	+++	++
PS	-	-	-	-	-	-	+	-	++	-	+++	-
MF	-	-	+	+	++	++	+++	+++	+++	+++	+++	+++

N: Normal littermates; T: Trisomy 16 mice. PM: Myenteric plexus; PS: Submucosal plexus; MF: Mesentery nervour fiber; -: No neurons and immunoreactive nerve fibers detected; +: A few scattering neurons and no enteric plexus or sparse immunoreactive fibers detected; +: Lowly developed enteric plexus or moderate immunoreactive fibers detected; +++: Moderately developed enteric plexus or abundant immunoreactive fibers detected; ++++: Fully developed enteric plexus or very abundant immunoreactive fibers detected.