[Effects of intraperitoneal injection of marrow mesenchymal stem cells on intestinal barrier in acute pancreatitis].

OBJECTIVE: To explore the effects of intraperitoneal injection of mesenchymal stem cells (MSC) on intestinal barrier in serve acute pancreatitis (SAP) rats. METHODS: MSC were harvested and cultured from femurs of one male SD rat. And 30 female SD rats were divided into 3 groups: control group (n = 6), SAP group (n = 12) and MSC transplantation group (n = 12). SAP was induced by intraperitoneal injection of L-arginine (2 g/kg) twice in SAP and MSC groups. In MSC group, the third-generation MSC (5×10(6)) were injected intraperitoneally once daily for 3 days. All rats were sacrificed after 72 h. The histomorphologic alternations of small intestine were measured to evaluate the therapeutic effect of MSC transplantation. Reverse transcription (RT)-PCR were used to identify the expression of TNF-α mRNA and IL-1ß mRNA in small intestine and pancreas. Small intestine and pancreatic samples were examined for the engraftment of donor-derived MSC by Y chromosome in situ hybridization analysis. RESULTS: Compared with SAP group, histomorphologic alternations of small intestine significantly lower in MSC group (4.17 ± 0.28 vs 3.00 ± 0.33, P < 0.05). The relative expression quantity of TNF-α mRNA and IL-1ß mRNA in pancreas were both significant higher in SAP and MSC groups than those in control group (3.10 ± 0.73 and 1.92 ± 0.37 vs 0.51 ± 0.24, 4.60 ± 0.59 and 2.43 ± 0.39 vs 1.15 ± 0.18, all P < 0.05). Compared with SAP group, the expression quantity of TNF-α mRNA and IL-1ß mRNA in pancreas significantly lower in MSC group (both P < 0.05). The relative expression quantity of TNF-α mRNA and IL-1ß mRNA in small intestine were both significant higher in SAP and MSC groups than those in control group (2.73 ± 0.91 and 1.55 ± 0.48 vs 0.62 ± 0.20, 5.20 ± 0.94 and 2.10 ± 0.34 vs 0.99 ± 0.10, all P < 0.05). The expressions of TNF-α mRNA and IL-1ß mRNA in MSC group were lower than those in SAP group (both P < 0.05). Sry gene was not detected in pancreatic and intestinal tissue of MSC-treated rats. CONCLUSIONS: Syngraft MSC exert protective effects on pancreas and small intestine injury. And their beneficial effects are primarily mediated via indirect actions but not by their differentiation into target cells.