ABSTRACT
The development and maturation of oligodendrocyte require complex mechanisms that interact at different levels to regulate neuronal activities. This review examines specific functions and critical roles of oligodendrocyte, regulatory factors involved in its differentiation, including the involvement of glutamate and reactive oxygen species (ROS). Olig2, Id4, Wnt/ß-catenin and histone deacetylase (HDAC) appear to play crucial roles in spatio-temporal regulation of the differentiation of oligodendrocytes. Furthermore, HDAC appears to be the rate-limiting factor that may be manipulated to promote myelination as it simultaneously allays contact inhibition of Id4 in the intrinsic pathway and Wnt/ß-catenin in the extrinsic pathway. ROS exhibit autocrine effect in enhancing functional activities of N-methyl-d-aspartate (NMDA) in neurogenesis and also play a secondary role in stimulating oligodendrocyte differentiation. It is concluded that the understanding of how regulators of oligodendrocyte interact may pave way for manipulation of oligodendrocytes in the management of neurodegenerative disorders.
ABSTRACT
The aim of this study was to investigate the ameliorative effect of Lawsonia inermis Linn used traditionally against trypanosomosis. Twenty-five adult Wistar rats of both sex were individually infected intraperitoneally (IP) with 106Trypanosoma congolense per ml of blood. Following establishment of infection, the rats were randomly divided into five groups of 5 rats each. Rats in groups I, II, and III were treated with 125, 250 and 500 mg/kg of the extract, respectively, while rats in groups IV and V were treated with 3.5 mg/kg and 2 ml/kg of diminazene aceturate (DM) once and physiological buffered saline, respectively. All treatments except DM were given orally for 7 days IP. The antitrypanosomal effect of the plant was assessed by observing the level of parasitaemia daily, packed cell volume (PCV) weekly, erythrocyte osmotic fragility (EOF) and malondialdehyde (MDA) concentration on day 21. Phytochemical screening of the extract revealed the presence of alkaloids, carbohydrates, triterpenes, steroids, cardiac glycosides, saponins, tannins and flavonoids. The extract significantly (P < 0.05) reduced levels of parasitaemia at 250 mg/kg. PCV was higher (P > 0.05) in extract treated groups but significantly higher (P < 0.05) in group II at week 2 when compared to group V. Rats in group II had significantly lower values of EOF and MDA when compared with groups IV and V. Thus, the leaf of L. inermis has in addition to an antitrypanosomal effect against T. congolense in rats, an attenuating effect on the trypanosomosis pathology probably mediated via protection of the erythrocyte membrane against trypanosome-induced oxidative damage to the erythrocytes.
