Role of dopamine receptor in intestinal mucosal barrier change after brain injury in rats / 中华创伤杂志

ABSTRACT

Objective To investigate the effect of dopamine receptor in intestinal mucosal barrier function after brain injury in rats.Methods Twenty-four rats were allocated to control group,brain injury group,dopamine receptor group,and dopamine antagonist group according to the random number table,with 6 rats per group.Feeney' s weight-drop model was introduced to generate rat models of brain injury.Intestinal mucosal specimens were harvested at postoperative 7 days to evaluate intestinal mucosal morphology by HE staining,expressions of dopamine receptor D1 (DRD1) and dopamine receptor D2 (DRD2) by immunohistochemistry,and mRNA and protein expressions of DRD1 and DRD2 by real-time PCR and Western blot.Meantime,urinary samples were collected to measure lactulose to mannitol ratio (L/M) by high performance liquid chromatography (HPLC).Results Intestinal villus integrity was disrupted in brain injury group and dopamine receptor group when compared to control group,but it remained relatively intact in dopamine antagonist group.Ratio of L/M in brain injury group and dopamine receptor group was similar (0.192 ± 0.080 vs 0.183 ± 0.090,P ＞ 0.05),far higher than 0.037 ± 0.008 in control group (P ＜0.01),but it was reversed in dopamine antagonist group (0.071 ± 0.008,P ＜ 0.01).Real-time PCR showed DRD1 and DRD2 mRNAs expressed in brain injury group and dopamine receptor group were similar (0.764 ± 0.074 vs 0.718 ± 0.065,0.439 ± 0.051 vs 0.408 ± 0.090,P ＞ 0.05),far higher than 0.189 ± 0.008 and 0.076 ± 0.011 in control group (P ＜ 0.01),but both lowered in dopamine antagonist group (0.386 ± 0.071,0.270 ± 0.092,P ＜ 0.01).estern blot analysis showed DRD1 and DRD2 proteins in brain injury group and dopamine receptor group were similar,but both were far higher when compared to control group (P ＜ 0.01).Conclusion Impaired intestinal mucosal barrier may be relate to the up-regulated dopamine receptor in intestinal mucosa after brain injury in rats.