The Effect of Oral Administration of Withania Somnifera Root on Formalin-Induced Pain in Diabetic Rats

Introduction: Hyperalgesia is considered as one the marked signs of subchronic diabetes mellitus that could affect the life style of the patients. With considering the potential anti-diabetic effect of the medicinal plant Withania somnifera (WS)(ashwagandha), this study was designed to investigate the analgesic effect of WS on formalin-induced nociceptive responses (standard formalin test) in diabetic rats. Methods: Rats were divided into control, WS-treated control, diabetic, sodium salicylate (SS)-treated control and diabetic and WS-treated diabetic groups. For induction of diabetes, streptozotocin (STZ) was used at a single dose. The treatment groups received oral administration of ashwagandha -mixed rat pellet (6025%) for two months; Results: The results showed that diabetic rats exhibited a higher score of pain at both phases of the formalin test and WS-treated diabetic rats exhibited a lower nociceptive score at both phases of the test (p 0.05). Meanwhile, SS administration significantly reduced pain score only at chronic phase of the test in the diabetic group (p 0.01). Discussion: Taken together, these results indicate that two-month administration of ashwagandha could attenuate nociceptive score in an experimental model of diabetes mellitus and this may be considered as a potential treatment for painful diabetic neuropathy.