Evaluation of the Effect of Acute and Chronic Restraint Stress on Inducible Nitric Oxide Synthase and Nitric Oxide Levels in Wound Healing Process in Rat

Considering that stress slows down wound healing, the main purpose of this study was to investigate the effects of acute and chronic restraint stress on inducible Nitric Oxide synthase (iNOS) and Nitric Oxide (NO) concentrations in wound tissue in rat.

48 male and female rats in 6 groups (n=8) including male control, male animals exposed to acute stress, male animals exposed to chronic stress, female control, female animals exposed to  acute stress and female animals exposed to chronic stress were used in this study. Tissue samples were collected on the 3rd and 7th days after wound creation. iNOS concentration were measured by ELISA method and the concentration of NO was measured by determining nitrite concentrations in the samples using Griess reagent.

Acute (P< 0.001) and chronic (P< 0.05) stress caused a significant increase in iNOS concentrations on the 3rd  and 7th days post wounding in male animals comparing to the control group. The concentration of iNOS was significantly increased in female animals only in the group exposed to the acute stress and on the 3rd day compared to the control group (P< 0.05). Acute and chronic stress caused a significant (P < 0.001) increase in NO concentrations in male animals when compared with the control group. NO concentrations was increased significantly in female animals exposed to acute stress comparing to the control group on 3rd day post wounding (P< 0.001).

Stress induced elevations in iNOS and NO concentrations could be one of the mechanisms underlying delayed wound healing by stress.