Figure 6.

mGluR5 antagonist MTEP significantly prevents intestinal epithelial barrier dysfunction, but has no obvious influence on the proproliferative effect of GLM in TPN mice. A–C) Intestinal villi and crypt measurements (A), PCNA- and BrdU-positive rate in the intestinal mucosal crypt (B), and levels of PCNA and pAkt (C). No significant differences in any of the measurements were observed with MTEP exposure in the WT or T1R3KO TPN + GLM (75 mM) mice. D) Ussing chamber and FITC-dextran permeability results. MTEP exposure significantly blocked the decline in TER and the increase in the FITC permeability rate induced by TPN + GLM treatments (75 mM), when compared with saline treatment in WT or T1R3KO mice. E) Protein expression of occludin and ZO-1 of isolated small-bowel IECs, determined by immunoanalysis. F) Representative images of IF staining of the TJ proteins occludin and ZO-1 in the villus region, with DAPI counterstaining. MTEP exposure markedly prevented the decline in occludin protein expression induced by TPN + GLM (75 mM) treatment when compared with saline treatment in WT or T1R3KO mice. Values are means ± sd (error bars). ns, not significantly different. *P < 0.05.