Effects of experimental ulcerative colitis on the myenteric neurons in the P2X7 knockout mice

Abstract The objective was to study the distal colon myenteric plexus and enteric glial cells (EGCs) in P2X7 receptor-deficient (P2X7-/-) animals after experimental ulcerative colitis on. 2, 4, 6-trinitrobenzene sulfonic acid (TNBS) was injected into distal colon of C57BL/6 (WT) and P2X7 receptor gene-deficient (P2X7-/-, KO) animals. Distal colon tissues were analysed 24 h and 4 d after administration. Double immunofluorescence was used for analyses and histology was used for morphological analysis. Quantitative analysis demonstrated 13.9% and 7.1% decreases in the number/ganglia of P2X7 receptor-immunoreactive (ir) in the 24 h-WT/colitis group and 4 d-WT/colitis, respectively. There was no reduction in the number per ganglia of neuronal nitric oxide synthase (nNOS)-ir, choline acetyltransferase (ChAT)-ir and PGP9.5 (pan neuronal)-ir neurons in the 4 d-KO/colitis group. There was a reduction by 19.3% in the number of glial fibrillary acidic protein (GFAP, EGC)-ir in the 24 h-WT/colitis group and a 19% increase in the number of these cells in the 4 d-WT/colitis group. There were no profile area changes in neurons in the 24 h groups. In the 4 d-WT/colitis and 4 d-KO/colitis groups, there was an increase in the profile neuronal area of nNOS, ChAT and PGP9.5. Histological analysis showed hyperaemia, oedema or cellular infiltration in the 24 h-WT/colitis groups and 4 d-WT/colitis groups. The 4 d-KO/colitis groups showed no histological changes.