Comparison of the effects of low intra-abdominal pressure and ischaemic preconditioning on the generation of oxidative stress markers and inflammatory cytokines during laparoscopy in rats.

Background: Pneumoperitoneum (Pp) induces ischaemia in intra-abdominal tissues. We investigated the effects of ischaemic preconditioning (IP) and low-pressure Pp methods used to reduce ischaemic injury during Pp on oxidative stress and inflammatory cytokine response.

Methods: Thirty-two rats were divided into four groups. Rats in the control group were subjected to only anaesthesia for 90 min. The other groups were subjected to Pp for 60 min with 15 (Pp15), 10 (Pp10) or 15 mmHg intra-abdominal pressure (IAP) after IP (IPPp15), all of which were followed by deflation (D) for 30 min. IP was defined as 10 min of Pp with 15 mmHg IAP followed immediately by 10 min of D. Peritoneum and blood samples collected at the end of the experiment were examined to determine inflammatory cytokine [tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6)], oxidative stress [malondialdehyde (MDA)] and antioxidant [reduced glutathione (GSH) and glutathione reductase (GR)] levels.

Results: Blood and peritoneum MDA values and peritoneum TNF-alpha and IL-6 values decreased, while GR values increased in the Pp10 group in comparison with the Pp15 group. Blood and peritoneum MDA, TNF-alpha and IL-6 values decreased and GR values increased in the IPPp15 group in comparison with the Pp15 group. Blood MDA and IL-6 values in the IPP15 group were lower than those in the Pp10 group, whereas GR values were higher in the former. Except for high peritoneal IL-6 levels, no difference was found between the parameters in the IPP15 and those in the control group.

Conclusions: IP may be more effective than low-pressure Pp in reducing ischaemic insult associated with laparoscopy.