Hyperbaric Oxygen Therapy in Rats Attenuates Ischemia-reperfusion Testicular Injury Through Blockade of Oxidative Stress, Suppression of Inflammation, and Reduction of Nitric Oxide Formation

Abstract

To evaluate the therapeutic utility of hyperbaric oxygen (HBO) therapy on testicular ischemia/reperfusion (I/R) injury and elucidate the underlying molecular mechanism, we tested whether HBO therapy provided rescue of the testes after torsion in rats. Sprague-Dawley rats were randomly divided into 4 groups: control group, control plus HBO therapy, I/R group, and I/R plus HBO therapy. The I/R model was induced by torsion of the right testis. I/R in the testis resulted in disrupted seminiferous tubules, germ cell-specific apoptosis, followed by a marked reduction in testis weight and daily sperm production. HBO therapy preserved seminiferous tubules, suppressed apoptosis, and prevented testicular atrophy in I/R testes. HBO therapy abated oxidative stress in I/R testes, marked by reduced malondialdehyde formation, enhanced activities of superoxide dismutase and heme oxygenase 1 (HO-1), and decreased activities of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and xanthine oxidase. HBO therapy resulted in a reduction of myeloperoxidase (MPO) activity in I/R testes, a marker of neutrophil recruitment. HBO therapy suppressed inflammation in I/R testes, marked by reduced messenger RNA (mRNA) levels of tumor necrosis factor-α (TNF-α), interleukin-1beta (IL-1β), and CD44. Furthermore, HBO therapy suppressed the activation of nuclear factor kappa B (NFκB), p38, and c-JUN-N-terminal kinase (JNK) signaling pathways in I/R testes. In addition, HBO therapy reduced nitric oxide formation in I/R testes through suppression of inducible nitric oxide synthase and dimethylarginine dimethylaminohydrolase. HBO therapy in rats attenuated I/R-induced testicular injury, possibly through abating oxidative stress, suppressing inflammation, and reducing nitric oxide formation.