Effects of pneumoperitoneum preconditioning on endothelial progenitor cells and renal protective mechanism in rats

Abstract

To explore the pneumoperitoneum-mediated renoprotective effects of preconditioning, mobilizing and homing of endothelial progenitor cells (EPCs) in rats. A total of 40 rats were randomized by a numerical table into 5 groups of gasless (C), pneumoperitoneum injury (Pp), long-term pneumoperitoneum preconditioning (P-L), mid-term pneumoperitoneum preconditioning (P-M) and short-term pneumoperitoneum preconditioning (P-S). C group had a pneumoperitoneum pressure of 0 mmHg; Pp group 15 mmHg, time 60 min; P-L, P-M, P-S groups were deflated and deflated preconditioning before pneumoperitoneum, then the same as Pp group, P-L group: inflation time was 25 min, gas discharge time 10 min; P-M group: 15 min, 10 min; P-S group: 5 min, 10 min. At 24 h post-operation, the animals were sacrificed by destroying cervical spine. And the specimens of venous blood and kidneys were harvested. Also the extent of renal injury, the homing of EPCs, the proliferation and angiogenesis of renal endothelial cell and the expression of angiogenic growth factor were analyzed. Compared with Pp group, P-L, P-M and P-S groups exhibited significant improvements in renal function, morphology and histological score (1.88 ± 0.35, 1.63 ± 0.52, 1.75 ± 0.46 vs 2.38 ± 0.52, all P < 0.05). The histological scores of P-M and P-S groups improved significantly versus P-L group (both P < 0.05). P-M and P-S groups showed no significant difference in histological score (P > 0.05). The number of EPCs in kidneys increased in P-L, P-M and P-S groups versus Pp group (2.18% ± 0.14%, 2.87% ± 0.29%, 2.90% ± 0.24% vs 1.73% ± 0.19%, all P < 0.05). The EPCs numbers of P-M and P-S groups were more than that of P-L group (both P < 0.05). And no significant difference existed between P-M and P-S groups (P > 0.05). Compared with Pp group, EPCs of P-L, P-M and P-S groups markedly increased in kidneys. No significant difference existed between P-M and P-S groups, but P-L group was the lowest. Also there was an up-regulated expression of stromal cell derived factor 1-α in pretreated kidneys versus Pp group (all P < 0.05). And P-M and P-S groups increased markedly. Pneumoperitoneum-mediated preconditioning protects against kidney injury by promoting EPC homing and enhancing endothelial cell and vascular proliferations. And short and medium-term preconditioning protocols are more effective for protecting kidneys.