Plasmodium berghei-induced malaria decreases pain sensitivity in mice

Onderstepoort Journal of Veterinary Research

Field Value
Title Plasmodium berghei-induced malaria decreases pain sensitivity in mice
Creator Oyewole, Aboyeji L. Akinola, Oluwole Owoyele, Bamidele V.
Subject Health science; biology; veterinary science inflammatory pain; malaria; infection pain; behaviour; opioidergic; serotoninergic
Description Various types of pain were reported by people with Plasmodium falciparum and were mostly attributed to a symptom of malarial infection. Neural processes of pain sensation during malarial infection and their contributions to malaria-related death are poorly understood. Thus, these form the focus of this study. Swiss mice used for this study were randomly divided into two groups. Animals in the first group (Pb-infected group) were inoculated with Plasmodium berghei to induce malaria whilst the other group (intact group) was not infected. Formalin test was used to assess pain sensitivity in both groups and using various antagonists, the possible mechanism for deviation in pain sensitivity was probed. Also, plasma and brain samples collected from animals in both groups were subjected to biochemical and/or histological studies. The results showed that Pb-infected mice exhibited diminished pain-related behaviours to noxious chemical. The observed parasite-induced analgesia appeared to be synergistically mediated via µ-opioid, α2 and 5HT2A receptors. When varied drugs capable of decreasing pain threshold (pro-nociceptive drugs) were used, the survival rate was not significantly different in the Pb-infected mice. This showed little or no contribution of the pain processing system to malaria-related death. Also, using an anti-CD68 antibody, there was no immunopositive cell in the brain to attribute the observed effects to cerebral malaria. Although in the haematoxylin and eosin-stained tissues, there were mild morphological changes in the motor and anterior cingulate cortices. In conclusion, the pain symptom was remarkably decreased in the animal model for malaria, and thus, the model may not be appropriate for investigating malaria-linked pain as reported in humans. This is the first report showing that at a critical point, the malaria parasite caused pain-relieving effects in Swiss mice.
Publisher AOSIS
Contributor Institution Based Research Fund (UIL/CREDIT/30 from TetFund, Nigeria) Staff Development Award (UIL/SSE/PF/5358 from University of Ilorin, Ilorin, Nigeria) AAU Small Grant for Thesis and Desertification (PC/6 from Association of African Universities)
Date 2021-01-11
Type info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion — —
Format text/html application/epub+zip text/xml application/pdf
Identifier 10.4102/ojvr.v88i1.1871
Source Onderstepoort Journal of Veterinary Research; Vol 88, No 1 (2021); 18 pages 2219-0635 0030-2465
Language eng
Coverage — — —
Rights Copyright (c) 2021 Aboyeji L. Oyewole, Oluwole Akinola, Bamidele V. Owoyele