Objective To investigate the protective effect of placental mesenchymal stem cells(P-MSCs)on pancreatic trauma(PT)in rats.Methods Sixty healthy adult male SD rats were randomly divided into control group,pancreatic trauma group(inject 1 ml of PBS solution locally in the pancreatic injury area and around the trauma area),and P-MSCs group[inject 1 ml of P-MSCs(1×106/ml)locally in the pancreatic injury area and around the trauma area],with 20 rats in each group.The pancreatic trauma rat model was established using a traumatic pressure of 400 kPa.Five rats were sacrificed at 1,3,5,and 7 d after modeling in each group,and serum and pancreatic tissue were collected.HE staining was used to observe the pathological changes of pancreatic tissue and pathological scores were performed.The ELISA method was used to measure the concentrations of serum amylase(AMS),lipase(LPS),tumor necrosis factor-α(TNF-α),interleukin-6(IL-6),IL-10,and transforming growth factor-β1(TGF-β1),as well as the activities of myeloperoxidase(MPO)and superoxide dismutase(SOD)in pancreatic tissue.The TUNEL method was used to observe the level of apoptosis in pancreatic tissue was observed by the TUNEL method.Results Compared with control group,pancreatic trauma group and P-MSCs group showed significant differences after pancreatic trauma,including the generation of peritoneal fluid increased(P<0.05),the ratio of pancreas to body weight and the total score of pancreatic tissue pathological damage increased(P<0.05),and serum levels of AMS,LPS,TNF-α,IL-6,and MPO activity increased early and showed a decreasing trend over time(P<0.05),while anti-inflammatory factors IL-10 and SOD activity showed an increasing trend over time(P<0.01),level of TGF-β1 in the early decline showed an upward trend over time(P<0.01),and the apoptosis index(AI)significantly increased(P<0.001).Compared with pancreatic trauma group,P-MSCs group showed an improvement in the overall morphology of pancreatic tissue,the generation of peritoneal fluid decreased(P<0.001),the pancreas to body weight ratio and the total score of pancreatic tissue pathological damage decreased(P<0.05),and serum levels of AMS,LPS,IL-6,TNF-α and MPO activity returned to normal levels faster(P<0.05);and the rate of anti-inflammatory factors IL-10,TGF-β1 and SOD activity elevation increased(P<0.05),the AI increased(P<0.001).Conclusion P-MSCs can achieve therapeutic effects on pancreatic trauma in rats by promoting pancreatic tissue repair,reducing local and systemic inflammation,improving tissue oxidative stress,and enhancing pancreatic acinar cell apoptosis.