Study on anti inflammatory effect of scorpion (Mesobuthus eupeus) venom in adjuvant-induced arthritis in rats

Rheumatoid arthritis is an autoimmune disease that causes chronic inflammation of the joints as well as other organs in the body. Adjuvant-induced arthritis models in inbred rats serve as relevant models for RA, having many clinical similarities to this disease. Using honey bee venom as a treatment for Rheumatoid arthritis is an ancient therapy in various parts of the world. However scorpion venom neurotoxins are responsible for toxicity and pharmacological effects. Twenty-five Wistar male rats weighing 110-130 g were divided in 5 groups and Arthritis was induced in them, using Freund’s adjuvant, except in group 1. In group 2 after the induction of arthritis no treatment was given. Group 3 received Betamethasone as an anti-inflammatory medicine. Venom (5µg/rat) was used in group 4 as a treatment and Group 5 received crude venom (10µg/rat) as treatment, after R.A induction, all the animals received treatment near the site of tibio-tarsal joint subcutaneously. The clinical features of the adjuvant induced arthritis like difficulty in movement and edema in joint appeared 3 days after inoculation of adjuvant. The onset of inflammation was explosive occurring 13-15 days post inoculation with a peak onset at day15. After the treatment of rats, there was a significant reduction in score of arthritis index in all treated animals. The changes in size of tibio-tarsal joint region in groups 4 and 5 which received crude scorpion venom and group 3 with Betamethasone treatment after arthritis development decreased. At the end of experiment, blood collection for WBCs count was carried out. In 2 (untreated rats) and Betamethasone treated rats, there was a significant rise in WBCs count. However in venom treated rats the rise in WBCs was not significant as compared to group 1 rats. The present study demonstrated that the scorpion (Mesobuthus eupeus) venom could be effective as anti-arthritis agent in animal model of acute inflammation. More studies are needed to be carried out to find the mechanism of the venom and exact therapeutic doses of the venom for acting as anti-arthritis agent.