Neuroprotective Effect of Dexamethasone on the Morphology of the Irradiated Post Natal Developing Cerebellum of Wistar Rat (Rattus norvegicus)

• Published in: International journal of morphology Vol. 24; no. 2; pp. 221 - 229
• Main Authors: Malomo, A.O, Ekpo, O.E, Imosemi, I.O, Owoeye, O, Osuagwu, F.C, Avwioro, O.G, Shokunbi, M.T
• Format: Journal Article
• Language: English; Spanish
• Published: Universidad de La Frontera, Facultad de Medicina 01.06.2006; Sociedad Chilena de Anatomía
• Subjects: ANATOMY & MORPHOLOGY; Desarrollo del cerebelo; Dexamethasone; Dexametasona; Morphology; Developing cerebellum; Irradiation; Morfología; Irradiación
• ISSN: 0717-9502; 0717-9367; 0717-9502
• DOI: 10.4067/S0717-95022006000300017

The neuroprotective effect of dexamethasone on the irradiated postnatal developing cerebellum of Wistar rat was studied. Seventy-five (day 1 old) neonates were separated into three groups; control group receiving no drug and no irradiation, irradiated group, and irradiated and dexamethasone group in which the dexamethasone was administered one hour before exposure to 5Gray (5Gy) of gamma rays. On complete exposure to the various interventions, the cerebellar tissues of animals from each group on days 5, 9, 14, 21 and 25 were processed for histological and histomorphometric studies. The result of the study showed that irradiation alone significantly reduced the thickness of the external granular layer (EGL) on day 5 and 14 at P<0.05, molecular layer (ML) on days 5, 9, 14 and 21 at P<0.05 and the granule layer (GL) on days 5, 9, 14 and 25 at P<0.05. When dexamethasone was combined with irradiation, a thicker and significantly different EGL on days 5, 9 and 14, ML on days 5, 14 and 21, and GL on days 5 and 14 was observed compared with the irradiated group at P<0.05. The Purkinje cell (PC) diameter even though was significantly reduced in the irradiated group on days 14 and 21, was not significantly different when dexamethasone was administered to the irradiated animals on days 5, 9, 14, 21 and 25 at p>0.05. Histologically, the cells of the ML in the irradiated group on days 9 and 14 were heavily gliosed compared to the mildly gliosed control, and the irradiated and dexamethasone groups. There was distortion of the PC monolayer with some cells found in either the ML or GL in the irradiated group on days 5, 9, 14 and 25. From the result of the study, administration of 0.005ml dexamethasone intraperitoneallyone hour before exposure to irradiation appeared to protect the developing rat cerebellum against irradiation injury as seen when compared with the controls