Effects And Potential Mechanism Of Betulinic Acid On Intestinal Mucosal Injury Induced By Cyclophosphamide In Mice

Background:With the rapid development of animal husbandry,oxidative stress has become one of the common problems in large-scale farming.Oxidative stress can't be underestimated to the animal body since its hazards has been more and more serious.Therefore,the research and development of a variety of antioxidants to minimize its damage become more and more important.Betulinic acid(BA)is a pentacyclic triterpene extracted from the birch tree.BA exhibits a variety of biological activities,such as anti-tumor,anti-cancer,anti-oxidative stress,immunomodulatory,anti-virus and anti-inflammatory.However,the effect of BA on oxidative damage in intestine has not been demonstrated yet.Thus,the objectives of the present study are to investigate the effect that cyclophosphamide(Cy)induced intestinal mucosal injury via oxidative stress and immune injury could be ameliorated by BA and to understand its mechanism of action,which provide a theoretical basis for the establishment of new methods to alleviate intestinal injury and to explore new ways for the livestock and poultry immunomodulation,antioxidants,and livestock and poultry health culture.Objectives:1)To clarify the relationship between the protective effect of BA on intestinal mucosa and its activity of antioxidant stress;2)To explain the repairing effect of BA against in intestinal mucosa injury induced by Cy and its regulation mechanism.The current study would provide theoretical basis for further scientific research and industrial application of BA.Methods:A total of 50 male Kunming mice were randomly divided into five groups: the control group,the Cy group,the low,medium and high dose of BA with Cy group(0.05,0.5,and 5.0 mg/kg body weight,respectively).BA was administered orally to mice with 1% starch jelly daily for 14 days,while mice in control and Cy groups were given an equivalent amount of 1% starch jelly only.Mice were given a single dose of Cy intraperitoneal(50mg/kg body weight)8 h after the last administration of BA,while the control received an equal volume of sterile saline.Sixteen hours after Cy administration,the mice were weighed and sacrificed by cervical dislocation.The lymphoid tissue and liver were quickly excised.The activities of immunoglobulin sIgA in the ileal mucosa and the superoxide dismutase(SOD)in intestine,and the contents of reduced glutathione(GSH)and malondialdehyde(MDA)in intestine,and the levels of 23 cytokines in serum were measured,and the morphological changes of intestinal villi were observed by Hematoxylin and eosin(H& E)stain.The mRNA expression of Occludin,ZO-1,Claudin-1 and ???6 in intestine were detected by RT-PCR.Results:1)BA pretreatment inhibited the decline of SIgA level in intestinal mucosa induced by Cy,reduced the contents of GSH in small intestine,and decreased the contents of MDA and the activities of SOD in small intestine,liver and serum,and restored the morphology of intestinal villi in mice induced by Cy.2)BA pretreatment reduced the levels of IL-5?IL-12(p70)?IL-17?TNF-??IL-10 and the activities of AST,ALT,UREA in serum of mice induced by Cy.3)BA pretreatment increased the mRNA expression of Occludin,ZO-1,Claudin and ???6 in small intestine by RT-PCR which suggested BA could repair the intestinal mucosal barrier.Conclusions:BA has a protecting effect against Cy induced intestinal mucosal injury by enhancing antioxidant capacity and immunoregulation capability,and increasing the expression of tight junction proteins in intestine.