The Effect Of Fecal Microbiota Transplantation On Visceral Sensitivity In Mice With DSS-induced Colitis

Objective: To observe the effects of fecal microbiota transplantation(FMT) on the abdominal myoelectric activities(AMAs), expression of substance P(SP) and calcitonin gene-related peptide(CGRP) in lumbosacral spinal in mice with dextran sulfate sodium(DSS)-induced colitis, and to explore the effect of FMT on visceral sensitivity in mice.Methods: Forty C57BL/6 male mice were randomly divided into two groups: group A(control group, 10 mice) and group M(model group, 30 mice). The mice in group A were free to drink sterile distilled water from the first day, the mice in model group received 2.0% DSS orally for 7 days and then distilled water for the rest days. Then the group M were subdivided into group B(sterile saline, 10 mice), group C(Bifico, 10 mice), group D(fecal microbiota transplantation, 10 mice). On the 11 th day, the mice in group A were given 1.0ml of sterile saline, group B were given 1.0ml of sterile saline, group C were given 1.0ml of Bifico suspension, group D were given 1.0ml of fecal microbiota suspension intracolonically on days 11, 13 and 15, the amount of enema was divided into twice a day. All mice were observed closely and characteristics of stool and body weight of each mouse were recorded to assess the disease activity index(DAI). The colonic tissue damage was evaluated. The AMAs at different levels of colorectal distension(CRD) were recored. The expressions of SP and CGRP in spine cord were detected by immunohistochemistry after CRD.Results:1. In group B, the DAI(1.57±0.93) and histopathologic score(1.63±0.74) were significantly higher than in group A(0.17±0.28 and 0.33±0.52, P<0.05), group C(0.54±0.43 and 0.67±0.52, P<0.05) and group D(0.46±0.43 and 0.57±0.53, P<0.05). However, there were no significant difference found in the DAIand histopathologic score among group A, group C and group D(P>0.05).2. The AMAs with colonic distention by 0.04, 0.06, 0.08 ml were significantly decreased in group A(12.38±1.22, 17.89±1.16 and 21.37±0.87μV), group C(13.10±1.63, 17.40±1.10 and 22.17±1.01μV) and group D(12.48±0.99, 18.02±0.49 and 22.65±0.96μV) than in group B(14.69±1.14, 21.30±0.79 and 24.91±0.76μV, P<0.05).3. The expression of SP in lumbosacral spinal cord in group B(0.241±0.025) were significantly higher than in group A(0.168±0.027, P<0.05), group C(0.175±0.039, P<0.05) and group D(0.180±0.049, P<0.05), however, there were no significant difference found in the expression of SP among group A, group C and group D(P>0.05). There was no significant difference found in the expression of CGRP in lumbosacral spinal cord in all groups(P>0.05).4. There was a positive relationship between the mean optical destiny of SP and the AMAs with colonic distention by 0.04, 0.06, 0.08ml(r>0.00, P<0.05), but there was no correlation between the mean optical destiny of CGRP and the AMAs.Conclusion: Fecal microbiota transplantation can alleviate the visceral hypersensitivity of DSS-induced colitis in mice, and it can significantly decrease the expression of SP in mice lumbosacral spinal cord. It may reduce the visceral sensitivity by inhibiting SP expression in spinal dorsa1 horn.