Oral buprenorphine is anti-inflammatory and modulates the pathogenesis of streptococcal cell wall polymer-induced arthritis in the Lew/SSN rat

Abstract

This study was carried out to determine an effective regimen for pain management in streptococcal cell wall (SCW)-induced arthritis in female Lew/SSN rats. Forty weanling rats (in 2 groups) were trained to accept disks of jelly as part of their dietary regimen. At 8 weeks of age weighing 150 g, SCW arthritis was induced and sublingual buprenorphine tablets were incorporated into the jelly disks to alleviate the pain of acute arthritis, which developed 24 h post-induction. Group A rats received buprenorphine at a rate of 1 mg/kg 12 hourly. Group B rats received buprenorphine at a rate of 2 mg/kg 12 hourly. Both groups of rats were monitored for symptoms of distress using an adaptation of the Morton and Griffin scale of adverse reactions. Group A rats with severe arthritis required additional subcutaneous (s.c.) injections of buprenorphine to alleviate the adverse effects of arthritis. Group B rats, with twice the dose of buprenorphine did not require additional s.c. injections of buprenorphine. Histological sections of rat hocks indicated that the inflammation was suppressed in Group B rats. We concluded that oral administration of buprenorphine is an effective method of pain management in the pathogenesis of SCW-induced arthritis in Lew/SSN rats. In this model of arthritis, oral buprenorphine has a significant anti-inflammatory effect and appears to modulate the destructive arthritic phase in joints in this animal model of arthritis.