Study On The Protective Effect And Mechanism Of MS-SOD On Intestinal Mucosal Injury Induced By Chemotherapy

Objective:Intestinal mucosal injury,including mucositis and diarrhea,is a common side reaction in the chemotherapy,which seriously affects the progress of chemotherapy and treatment results.But there are no effective treatment drugs,so it is urgent to develop safe and effective drugs in clinical practice.Superoxide Dismutase(SOD)can remove reactive oxygen species(ROS)and is considered as a potential drug to treat intestinal mucosal injury.MS-SOD(MS-Superoxide Dismutase)is a new type of manganese SOD,which has been granted a national patent with new sources and new functions.Compared with similar products,MS-SOD has prominent comprehensive advantages:heat resistance,acid and alkali resistance,trypsin resistance and pepsin resistance,so it can be orally administered without being degraded by gastrointestinal tract.However,there have been no reports on the pharmacological activity of MS-SOD.The purpose of this study was to investigate the protective effect of MS-SOD on intestinal mucosal injury caused by chemotherapy and to explore the active mechanism.Methods:Intestinal mucosal injury model was established in C57/BL6 mice and induced by 5-Fluorouracil(5-FU).This model was established to explore the protective effect of MS-SOD at different doses and at different times of administration.The preliminary efficacy of MS-SOD was determined by monitoring the body weight,diarrhea and blood in the stool of mice.At the time of anatomy,the intestinal length of mice was measured,and H&E(Hematoxylin and Eosin)staining was used to further determine the efficacy through pathological diagnosis.ROS content in the intestinal tissue in mice was detected using the special test kits.The expression of intestinal inflammation factors was detected by real-time fluorescence quantitative Polymerase Chain Reaction(PCR)technology.And the intestinal flora in mice was detected using the second generation sequencing.We study the effects of MS-SOD in this mice model and put forward the reasonable effective mechanism from the above several aspects to.In addition,in order to verify the safety of MS-SOD,immunogenicity detection of MS-SOD was conducted in this studyResults:The intestinal mucosal injury model of C57/BL6 mice was successfully constructed by injection of 50mg/kg 5-FU for 5 consecutive days,which showed the symptoms of weight loss,diarrhea and hematochezia in the mice.The results of tissue sections showed that the villi of the small intestine were significantly shortened and the recesses of the crypt disappeared after 5 days.At the same time of modeling,MS-SOD of 200,400 and 800U/10g were given for intervention,and the results showed that 800U/10g MS-SOD had a significant effect.Then,800U/10g MS-SOD was administered for 3,5,7 and 9 days respectively,and it was found that continuous administration for 5 days could alleviate intestinal mucosal injury.However,intestinal mucosa had the ability of self-recovery after the inj ection of molding agent was stopped,and the efficacy of MS-SOD was weak.Finally,800U/10g MS-SOD was determined to be the best therapeutic regimen for the model drug at the same time and continuously for 5 days,and the pharmacology mechanism was studied on this basisFirst,we detected the ROS and antioxidant capacity of small intestinal tissues,and found that MS-SOD could decrease ROS and increase the antioxidant capacity of tissues caused by 5-FU,and alleviate the level of oxidative stress.In addition,MS-SOD can reduce the expression of related pro-inflammatory factor mRNA and reduce the level of inflammation.Finally,the sequencing results of intestinal flora showed that after 5-FU modeling,the relative abundance of Verrucomicrobia increased.MS-SOD intervention changed this trendThe immunogenicity test showed that there was no specific antibody in the serum of mice after oral MS-SOD,so it was believed that MS-SOD would not cause immunogenicity after oral administration.At the same time,after 5 days of gavage with 2000U/10g MS-SOD,the mice showed no pathological manifestations in weight,fecal morphology,intestinal integrity or serology,indicating that the oral administration of high-dose MS-SOD was safe for miceConclusion:MS-SOD could alleviate the intestinal mucosal injury caused by 5-FU in mice,which was manifested as reducing the symptoms of weight loss,diarrhea and blood stool.It may exert its effects through the following three aspects:it reduced the content of reactive oxygen species and improved the antioxidant capacity in intestinal tissues;it reduced the level of inflammation;it changed the intestinal flora.In addition,this study verified that oral administration of MS-SOD did not cause immunogenicity.Therefore,MS-SOD,as a safe and effective new type of superoxide dismutase,is expected to be developed into clinical medicine.