Effects of intraperitoneal hydrogen injection on nitric oxide synthase mRNA and malondialdehyde following limb ischemia-reperfusion in rabbits.

Objective: The purpose of this study was to investigate the effects of intraperitoneal hydrogen (H2) injection on the mRNA expression levels of inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS) as well as the serum malondialdehyde (MDA) level in a rabbit model of limb ischemia-reperfusion (I/R)-induced skeletal muscle injury.

Methods: To establish the hind limb I/R animal model, 30 rabbits were randomly assigned to one of 3 groups: sham, I/R, and ischemia-reperfusion + H2 (IRH). An intraperitoneal injection of H2 was given to the IRH group, while an equivalent amount of air was given to the sham and I/R groups. At 3, 6, 12, and 24 h after reperfusion, serum MDA level as well as skeletal muscle iNOS and eNOS mRNA expression levels were determined.

Results: Both iNOS mRNA expression and serum MDA levels were higher in the I/R group than the sham group (p<0.01) and lower in the IRH group than the I/R group (p<0.01, p<0.05, respectively) at various time points after reperfusion. The eNOS mRNA expression level exhibited no significant difference between the I/R and sham groups after reperfusion but was significantly higher in the IRH group than in the sham group (p<0.01, p<0.05, respectively).

Conclusion: During the I/R process, the expression of iNOS mRNA was up-regulated along with an increase in MDA. Intraperitoneal injection of H2 can down-regulate iNOS mRNA expression and up-regulate eNOS mRNA expression in the I/R process, suggesting a protective effect of H2 in I/R-induced skeletal muscle injury.