Hypoxia preconditioning protects Ca(2+)-ATPase activation of intestinal mucosal cells against R/I injury in a rat liver transplantation model

AIM: To investigate the effect of ischaemia and reperfusion (I/R) injury on the Ca(2+)-ATPase activation in the intestinal tissue of a rat autologous orthotopic liver transplantation model and to determine if hypoxia preconditioning (HP) therapy induces HIF-1α to protect rat intestinal tissue against I/R injury. METHODS: Rats received non-lethal hypoxic preconditioning therapy to induce HIF-1α expression. We used an autologous orthotopic liver transplantation model to imitate the I/R injury in intestinal tissue. Then, we detected the microstructure changes in small intestinal tissues, Ca(2+)-ATPase activity, apoptosis, and inflammation within 48 h postoperatively. RESULTS: HIF-1α expression was significantly increased in intestinal tissue at 12 h postoperatively in rats that were exposed to a hypoxic environment for 90 min compared with a non-HP group (HP vs AT, P = 0.0177). Pathological analysis was performed on the intestinal mucosa cells, and the cells in the HP group appeared healthier than the cells in the AT group. The Ca(2+)-ATPase activity in the small intestinal cells in the AT group was significantly lower after the operation, and the Ca(2+)-ATPase activity in the HP group recovered faster than that in the AT group at 6 h postoperatively (HP vs AT, P = 0.0106). BCL-2 expression in the HP group was significantly higher than that in the AT group at 12 h postoperatively (HP vs AT P = 0.0010). The expression of the inflammatory factors NO, SOD, IL-6, and TNF-α was significantly lower in the HP group than in the AT group. CONCLUSION: Hypoxia-induced HIF-1α could protect intestinal mucosal cells against mitochondrial damage after I/R injury. HP could improve hypoxia tolerance in small intestinal mucosal cells and increase Ca(2+)-ATPase activity to reduce the apoptosis of and pathological damage to intestinal cells. HP could be a useful way to promote the earlier recovery of intestinal function after graft procedure.