Neurohistochemistry and Immunological Assessment of Cerebellar-hippocampal Connectivity Following Artequin Exposure in Adult Wistar Rats

Abstract

Background and Aims: Artequin, a commonly used artemisinin-based antimalarial therapy, has been associated with central nervous system side effects, yet its effects on hippocampal–cerebellar function remain unclear. This study investigated it neurohistochemistry, immunoreactivity and neurobehavioral parameters in hippocampal – cerebellar connectivity in adult Wistar rats. Study Design:  Forty-two inbred adult male Wistar rats of average weight 200 g were divided into groups 1–6. Group 1 served as the control that received 5 ml kg-1 of water, while groups 2–6 received oral doses of 0.86/1.07 mg kg-1 (ATQ1), 1.71/2.14 mg kg-1 (ATQ2), 3.42/4.28 mg kg-1 (ATQ3), 6.84/8.56 mg kg-1 (ATQ4) and 13.68/17.12 mg kg-1 (ATQ5) body weight of artequin for three days. T – maze neurobehavioral tests were carried out two days prior and after the administration of artequin Place and Duration of Study: Department of Zoology, Faculty of Biological Sciences, Akwa Ibom State University, Nigeria and Department of Anatomy, Faculty of Basic Medical Sciences, University of Uyo, Akwa Ibom State, Nigeria, between June 2024 and July 2024. Methodology: Immediately after the neurobehavioral test, the animals were sacrificed after they were deeply anesthetized with ketamine–hydrochloride. The brains were perfused fixed in 10 % buffered formalin. They were processed using Cresyl violet staining methods for neuronal morphology and immunohistochemical labelling for neurofilament proteins (NFL). Results: In the T- maze test, the artequin groups had significantly lower (p = 0.05) spontaneous alternation than the control group. Histochemical evaluations of the hippocampus and cerebellum of all the animals that received artequin showed histopathological features including karyorrhexis, hypertrophy and chromatolysis with decreased Nissl substance intensity and cellular densities. Immunohistochemical labeling revealed decreased expression of neurofilament proteins (NFL) in both brain areas in the treatment groups. Conclusion: Artequin administration induced a dose-dependent adverse effects on the histochemistry and neurofilament protein immunolabelling of the hippocampus and cerebellum. This may suggest neuronal and glial degeneration, which may result in altered hippocampal - cerebellar interactions and functions.