What should be the ideal time for ischemic preconditioning in a laparoscopic rat model?

Pneumoperitoneum (Pp) induces an ischemia and reperfusion (I/R) injury as a result of released oxidative stress markers. Ischemic preconditioning (IP) is one of the used methods to reduce the harmful effects of Pp, which is a mechanism for reducing organ I/R injury by a brief period of organ ischemia. The aim of this study was to investigate the ideal time for IP in the laparoscopic model.

Thirty-two rats were assigned into four groups: group 1 (control, n = 8) was subjected to a sham operation. Group 2 (5-minutes IP, n = 8) was subjected to 5 minutes of Pp with 15 mm Hg of pressure followed immediately by 5 minutes of deflation, and after that, 60 minutes of Pp with 15 mm Hg, followed by 60 minutes of deflation. Group 3 (10-minutes IP, n = 8) was subjected to 10 minutes of Pp and 10 minutes of deflation. Group 4 (Pp only, n = 8) was subjected to 60 minutes of Pp with 15 mm Hg of pressure, followed by 60 minutes of deflation. At the end of the experiment, plasma malondialdehyde (MDA) values, the oxidative stress marker, and plasma-reduced glutathione (GSH) levels, the marker showing antioxidant activity, were determined.

Highest plasma MDA values were in group 4 (Pp only), followed by groups 2 and 3 and group 1 (P = 0.181). In addition, IP groups had almost the same values for MDA. Plasma GSH levels in the control group were significantly higher than those in the IP groups and the Pp-only group (P < 0.001). Similarly, as in MDA levels, no difference was found between plasma GSH levels of the IP 5-minutes and IP 10-minutes groups.

Five minutes of the IP model may be as reliable as 10 minutes of the IP model. In that case, 5 minutes of IP can be more suitable in reducing I/R injury in laparoscopy.