| Objective: to observe therapeutic effect of rat bone marrow derived mesenchymal stem cells(BM-MSCs)on radiation-induced small intestinal injury,to explore the effect of BM-MSCs on the expression of apoptosis gene in small intestine of rat exposure to radiation and analyze the relationship between them.Methods: forty-five rats were divided randomly into 3 groups(cont rol group?radiation group and treatment group),with 12 rats in each group.Radiation group was treated with a sing dose of 12 Gy whole b ody Co60 ? radiation,within 2 hours after which,radiation group wa s injected with 1 ml normal saline via tail vein;treatment group was treated with a sing dose of 12 Gy whole body Co60 ? radiation,with in 2 hours after which,treatment group was injected with 1 ml norma l saline containing 1×10^6 BM-MSCs;control group was only injecte d with 1 ml normal saline in the same manner in the same period.Clinical observation,including stool consistency?food intake?mentality?activity?gross appearance of small intestine and body weight,was per formed.On the fourth day following radiation,sample collection was performed.The collected small intestine sample was used for histologi cal examination after HE stain?observation of cell apoptosis after TU NEL stain and detection of expression of small intestine apoptosis gen e by gene chip technology,while the collected blood was used for det ection of serum IL-6 and endotoxin by ELISA.Results:1.clinical observation: gross appearance of small intestine of rat in control group is normal,which is characterized by no congestion and edema in small intestinal wall and no visible intestinal tympanites;in radiation group,obvious intestinal tympanites in small intestine and part of colon,particularly in small intestine near the ileocecal valve,and marked congestion and edema in small intestinal wall were observed;while in treatment group,congestion and edema of small intestinal wall were slight and intestinal tympanites was only observed in small intestine near the ileocecal valve;control group showed granular and black stool,while yellow and loose stool was observed in radiation group,which has no significant difference in treatment group compared with control group;in control group,rats were sensitive to external stimuli,active,in good mental status and ingested food normally;while in radiation group,rats were insensitive,inactive,in poor mental state and with obviously decreased food intake,which had no significant difference in treatment group compared with control group;fourth day after radiation,no significant difference was observed in weight loss in each group.2.villus height of small intestine: compared with control group,the villus height of small intestine in both radiation group and treatment group were significantly decreased,which was increased in treatment group while compared with radiation group(P < 0.05).3.intestinal mucosal injury score: compared with control group,intestinal mucosal injury score in both radiation group and treatment group were significantly increased,which was decreased in treatment group while compared with radiation group(P < 0.05).4.serum IL-6 concentration: compared with control group,serum IL-6 concentration in both radiation group and treatment group were significantly increased,which was decreased in treatment group while compared with radiation group(P < 0.05).5.serum endotoxin level: compared with control group,serum endotoxin level in both radiation group and treatment group were significantly increased,which was decreased in treatment group while compared with radiation group(P < 0.05).6.cell apoptosis in small intestinal crypt: compared with control group,cell apoptosis in intestinal crypt in both radiation group and treatment group were significantly increased,which was decreased in treatment group while compared with radiation group(P < 0.05).7.gene P53 expression of small intestine tissue: compared with control group,the fold change of gene p53 in small intestinal tissue in radiation group is 2.261,which is 0.453 in treatment group while compared with radiation group,suggesting that gene P53 expression of small intestinal tissue in rat exposure to radiation is down-regulated by BM-MSCs.Conclusion: BM-MSCs had therapeutic effect on radiation-induced small intestinal injury in rat,which may be related with its inhibitive effect on the expression of small intestinal gene P53.The small intestinal gene P53 may be a therapeutic target points for radiation-induced small intestinal injury. |
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