The Antioxidant and Anti-Inflammatory Effects of Ischemia Post-Conditioning on the Injury Induced by Ischemia/Reperfusion in the Rat Liver

Ischemia-reperfusion injury (IRI) can induce major changes in the function of different organs, including the liver. Studies have indicated that ischemic post-conditioning (HIPO) can protect the tissues against ischemia-reperfusion injury.

To investigate the antioxidant and anti-inflammatory effects of ischemia post-conditioning against the IRI of the rat liver through four 30-second cycles of alternating ischemia and reperfusion, before 24-hour persistent reperfusion.

Fifteen rats were randomly divided into 3 groups 1) operation control group, 2) ischemia-reperfusion (IR) group whose liver was exposed to 60-miute ischemia of by 24-hour reperfusion and 3) ischemic post-conditioning (IR+IPO) group underwent the same procedure as the second group except that before persistent reperfusion, the rats were subject to post-conditioning by four 30-second cycles of alternating ischemia and reperfusion. The changes induced by IRI and the antioxidant and anti-inflammatory effects of ischemic post-conditioning were assessed by the serum level of IL-6 using the ELISA method, malondialdehyde (MDA), and total antioxidant capacity (TAC). 

Ischemic post-conditioning potentiated antioxidant effects and reduced the inflammation caused by the IR in the liver. The serum level of IL-6 reduced from 394.4±126.4 to 124.4±29.07 pg/ml (post-conditioning group), and the tissue MDA reduced from 431.4±76.53 to 207.2±25.77 nmol/g) compared to the IR group. The data revealed that the levels of the indices returned almost to the level of the operation control group (P<0.001). Additionally, the total antioxidant capacity of the liver significantly improved (P<0.01) from 11.58±1.87 (in the IR group) to 17.53±2.51 mmol/mg (in the IR+IPO group).

The study demonstrates that the protective effect of ischemic post-conditioning against IR-induced injury may be mediated through decreasing inflammation and improving antioxidant activities.