Effects of Morphine Dependency on Intervertebral Disc in the Rat

Background: a large proportion of patients presenting withlumbar disc disease are opium addicts in our region. it was,therefore, hypothesized that morphine might affect the intervertebraldisc. we investigated the histological findings ofmorphine dependency on intervertebral discs in rat.methods: forty nmri adult male rats (230-250 g) placed onordinary diet and received aqueous solution of morphine. thesolution contained 0.1 rng/ml on the first day which graduallyincreased to 0.3 mg/ml during the first week, then continued at0.4 mg/ml for four, seven and 11 weeks. morphine dependencywas confirmed by the presence of withdrawal syndromesusing intraperitoneal naloxone at the end of each period. theh&e stained tissues were used to study the structure of discand evaluation of degenerative changes.results: except for vascular proliferation of nucleus pulposus,an increase in the rate of matrix fibrillation, fibrosis, hyalinization,and dehiscence of nucleus pulposus was seen in morphinedependent rats compared with control group although itwas not statistically significant possibly owing to relativelylow sample size which limited the power to precisely revealthe difference. the duration of dependency did not affect thepathologic markers.conclusion: the results of this study suggest that morphinedependency induces some pathologic changes in the intervertebraldisc of the rat. further investigation into degenerativemarkers with larger sample size is required.