Hyperbaric oxygen preconditioning ameliorates anxiety-like behavior and cognitive impairments via upregulation of thioredoxin reductases in stressed rats

Abstract

The present study examined the protective effect of hyperbaric oxygen preconditioning (HBO-PC) and the role of thioredoxin reductase (TrxR) in a post-traumatic stress disorder (PTSD)-induced rat model by using single prolonged stress (SPS). Rats were randomly divided into Sham, HBO, SPS and HBO + SPS groups. HBO-PC was conducted by exposing rats to 100% oxygen at 2.5 atm absolute for 1 h each day for 5 consecutive days. SPS was performed 24 h after the last HBO-PC conditioning event. At 1 h, 6 h, 12 h, 24 h and 72 h after SPS, TrxR mRNA expression was analyzed in the hippocampus; Nissl and TUNEL staining were performed at 72 h after SPS. The results indicated that HBO-PC was able to significantly preserve viable neurons in the CA1 subfield of hippocampus following SPS exposure, as evidenced by reduced amounts of CA1 neuronal apoptosis. Furthermore, HBO-PC upregulate the expression of TrxR-1 and TrxR-2 mRNA in the hippocampus at 6 h and 12 h after SPS exposure and ameliorated anxiety-like behavior and cognitive impairments normally induced by SPS. Taken together, these findings suggest that HBO-PC is beneficial for the improvement of anxiety-like behavior and cognitive impairments induced by SPS exposure, and this effect might be associated with inhibition of neuronal apoptosis via upregulation of TrxR in stressed rats.