the antinociceptive effects of thymoquinone on acute postoperative pain: roles of spinal cord oxidative stress, inflammatory and apoptotic mechanisms involved

Pain is an important outcome of surgery, which in case of insufficient treatment can lead to chronic pain and its consequences (1). natural products with fewer side effects are used to optimize post-operative pain management. in the present study, the effect of thymoquinone (tq) on acute post-operative pain was investigated. the possible mechanisms were followed by measuring biomarkers of oxidative stress, inflammation and apoptosis in the spinal cord. celecoxib (clx), an inhibitor of the cyclooxygenase pathway, was used to compare the effects. acute post-operative pain was induced by surgical incision of the plantar skin and muscles (2). the tq and clx were orally administered and mechanical allodynia was measured using von frey filaments on days 1,2, 3, 5, 7, 9 and 11 after surgery. biomarkers of oxidative stress, inflammation and apoptosis were determined on post-operative days 1, 3 and 7. locomotor activity was also performed using an open-field test. in the vehicle-treated group, the fifty percentage of paw withdrawal threshold (pwt 50%) decreased at days 1, 2 and 3 and then, gradually returned to the pre-operative level. the tq (5 and 10 mg/kg) and clx (10 mg/kg) increased pwt 50%, and improved the spinal cord alterations of superoxide dismutase, malondialdehyde, tumor necrosis factor-alpha and caspase-3. locomotor activity was not affected by the above-mentioned treatments. oral administrations of tq and clx exhibited similar anti-allodynic effects. these mitigating effects might have occurred due to the inhibition of oxidative stress, inflammation and apoptosis in the spinal cord.