Influence of psychological stress on free radical metabolism of masseter muscle in rats

LI Qiang; ZHANG Min; CHEN Yong-jin; HUANG Fei

Abstract：AIM: To study the influence of psychological stress on the free radical metabolism of masseter muscle in rats. METHODS: Seventy - two SD male rats were randomly divided into control group, psychological stress group (PS group) and foot shock group (FS group), with 24 rats in each group. The PS group rats were placed into the communication box to receive the psychological stress produced by FS group rats when they receive foot shock. All the rats were bred in the same conditions. PS group rats and control group rats were executed and sampled at 1 week (1 w) 、3 weeks (3w) and 5 weeks (5w) separately to measure the activity of superoxide dismutase (SOD) 、gluta-thione peroxidase(GSH - Px) and catalase (CAT) and the content of malondialdehyde (MDA) in masseter muscle of rats. RESULTS: There were no obvious change in free radical metabolism in masseter muscle of rats between PS group and control group after 1 week psychological stress(P <0.05). However, the activity of SOD 、GSH - Px and CAT de-creasd (P < 0.05) and the content of MDA increased (P < 0.05) in PS group 3 weeks after stress . Though the activity of SOD and GSH - Px in the PS group of 5 weeks were elevated in comparison to the 3 weeks PS group of (P <0.05), but both are lower than the control group(P <0. 05, P <0. 01), and the content of MDA is increased (P<0.05). CONCLUSION: Psychological stress could result in the imbalance of free radical metabolism in masseter muscle of rats,which may be one of the etiologyical factor of dysfunction induced of masseter muscle by psychological stress.