Eur J Anat, 14 (2): 49-58 (2010)

Cerebellar reduction in rats by gamma irradiation is mitigated by pretreatment with methanolic extract of Vernonia amygdalina and alpha-tocopherol

Olatunde Owoeye¹, Ebenezer O. Farombi², Silas K. Onwuka³

¹Department of Anatomy, College of Medicine, University of Ibadan, Ibadan, Nigeria. ²Department of Biochemistry, College of Medicine, University of Ibadan, Ibadan, Nigeria. ³Department of Veterinary Anatomy, Faculty of Veterinary Medicine, University of Ibadan, Nigeria.

ABSTRACT This study evaluated the radioprotective effect of a methanolic extract of Vernonia amygdalina (MEVA), as compared with alpha-tocopherol (TOCO), on the effect of gamma-irradiation on the histomorphometry of the cerebellum of rats. Rats were administered with MEVA at 250, and 500 mg/kg/day, and TOCO at 500 mg/kg/day for 14 days, gamma-irradiated with 2.0 Gy on 15^th day, and euthanized on the 16^th day. Rat cerebella were processed for 5-6 µm paraffin-embedded sections and stained with Haematoxylin and Eosin and evaluated under the light microscope. The dimensions of the (i) the molecular layer (ML), (ii) the Purkinje layer (PL), (iii) the granular layer (GL), (iv) the density of Purkinje cell (DPc), and (v) the widest diameter of Purkinje cells (WDPc), were obtained using a microscope with a graticule. Data were analyzed using ANOVA. Gamma radiation caused a statistically significant reduction in the means of the PL (p<0.05), ML, GL, WDPc (p<0.01), and the DPc (p<0.001). Pretreatment with both 250 and 500 mg/kg doses of MEVA elicited a significant elevation of the means of these parameters when compared with the irradiation only groups as follows: PL (p<0.05), ML, GL, WDPc (p<0.01), and DPc (p<0.001). Similarly, pretreatment with TOCO elicited a significant elevation of the means of the same parameters thus: ML and GL (p<0.01), DPc and WDPc (p<0.001). Relatively, the 500 mg/kg dose of MEVA was more potent than the 250 mg/kg dose, and TOCO pretreatment was more potent than MEVA. The study demonstrates that pretreatment with MEVA and TOCO before exposure to 2 Gy of gamma rays significantly improves the radiation-induced changes in the cerebellum of Wistar rats.

Keywords: Central nervous system, Cerebellum, Irradiation, Vernonia amygdalina