Arachidonic acid metabolites,
prostaglandins and
leukotrienes are detected in clinical cases of herniated nucleus pulposus. However, little is known about their role in the associated symptoms like radicular
pain. The aim of the present study was to examine the role of
leukotrienes in an animal model of
hyperalgesia induced by application of autologus nucleus pulposus to sciatic nerve in rats.
Hyperalgesia was assessed employing noxious mechanical and thermal stimuli.
Zileuton, a
5-lipoxygenase inhibitor, dose dependently (25-100 mg/kg, p.o.), and
indomethacin (2 mg/kg, p.o.), a non-selective
cyclooxygenase inhibitor, significantly (P > 0.05) decreased mechanical as well as
thermal hyperalgesia on postoperative days 3, 5 and 7 as compared to the nucleus pulposus group. Further, co-administration of
zileuton (25 mg/kg, p.o.) with
indomethacin (2 mg/kg, p.o.) showed enhanced anti-hyperalgesic effect in both the paradigms as compared to effect per se. The present study, thus, suggested that
leukotrienes as well as
prostaglandins might play a significant role in
hyperalgesia induced by autologus nucleus pulposus in rats. The results suggested that dual inhibition approach of
5-lipoxygenase and
cyclooxygenase enzymes may prove beneficial in such conditions.