Effects of Xylopia aethiopica ethanolic fruit extract and Diclofenac Sodium on Nociception, inflammation and Sciatic Neuroarchitecture during Oxaliplatin therapy of Wistar Rat

Abstract

Oxaliplatin therapy presents a dose-limiting neuropathic pain that causes neurological/systemic inflammation.  Xylopia aethiopica (Negro pepper), as a medicinal plant, possesses analgesic properties. This study investigated the effects of ethanolic extract from Xylopia aethiopica on pain and inflammation in oxaliplatin therapy of Wistar rats. The rats were grouped into 5 groups (n=10): Except for the normal control, others were treated with oxaliplatin (8mg/kg of body weight, b.w.) once weekly. Toxicity study of Xylopia aethiopica Ethanoic Fruit Extract (XAEFE)   indicated a lethal dose of 7,483.31 mg/kg b.w. Except for the negative control, others were treated daily with diclofenac sodium (analgesic) at 10 mg/kg b.w. (positive control), XAEFE at 400 mg/kg b.w. and XAEFE at 800 mg/kg b.w.  respectively. Duration of treatments was 4 weeks after which they were assessed for nociception, Interleukin 1 beta (IL-1β), Interleukin 6 (IL-6) , monocytes and sciatic nerve histology. Writhing responses were significantly reduced in groups treated with XAEFE (P˂0.05). However, when compared against all the groups except for normal control, the commercial analgesic significantly reduced the writhes at P˂0.05.   At P˂0.05, the analgesic and XAEFE, at high dose, reduced the serum levels of IL-1β, IL-6 and monocytes when compared to negative group, with XAEFE showing increased reduction of IL-1β level when compared to the analgesic. Histological findings showed that XAEFE caused a normal sciatic nerve histology against those treated with the analgesic and oxaliplatin respectively. This study showed that Xylopia aethiopica may be more effective than the analgesic in offering protection against systemic inflammation and neurodegeneration.