Protective effects of hirudin against compartment syndrome in rabbits through the activation of Nrf2/HO-1

ABSTRACT Compartment syndrome generates an oxidative condition causing the death of skeletal muscle cells. Hirudin has antioxidant and anti-inflammatory properties. However, its correlation with the pathway of Nrf2/HO-1 for the protection of the skeletal muscle is unknown. We aimed to evaluate the protective efficacy of double-doses of hirudin in compartment syndrome and its association with Nrf2/HO-1 expression. Compartment syndrome was induced in rabbits and double-doses of hirudin (0-8 ATU/kg) were locally administered to select an optimal hirudin concentration that protects skeletal muscle from damage. The tissue structural changes, W/D ratio, lipid peroxidation level by MDA assay and inflammatory factors were determined in the skeletal muscle. To determine the musculoprotective efficacy of H8 at 72h timepoint after compartment syndrome, and its association with the Nrf2/HO-1 pathway, the following assays were performed by TUNEL assay and immunofluorescence: necrosis (high-mobility group box-1; HMGB1), Nrf2, and HO-1. In addition, the HO-1 mRNA was evaluated by qPCR. Hirudin in a dose of 8 ATU/kg (H8) presented the lowest levels of histological damage, fibrosis, W/D ratio and oxidative stress in the studied groups. Moreover, treatment with H8 markedly downregulated the level of inflammatory factors including TNF-a, IL-1β and IL-6. H8 showed a protective effect at 72h timepoint after compartment syndrome, as revealed by a decrease in the levels of all damage markers. Nuclear translocation Nrf2 and HO-1 staining in cytoplasm were increased, and the levels of HO-1 mRNA were also increased. In conclusion, double-doses of H8 alleviate the death of muscle cells induced by oxidative stress 72 h after compartment syndrome in rabbits. This protective effect is associated with the nuclear translocation of Nrf2 and an elevated expression of HO-1.