Neurotoxic effects of manganese chloride on the occipital cortex of adult wistar rats

Manganese (Mn) is the twelveth most abundant element on the earth. It is an essential trace metal that is required for a specific amount of enzymes required for normal cellular functions. Manganese deficiency and intoxication are associated with adverse metabolic and neuropsychiatric effects in humans. This study investigated the effect of manganese chloride on occipital cortex of adult Wistar rats.

Thirty-six (36) healthy adult Wistar rats of both sexes weighing between 120 – 200 g were separated into four groups; A, B, C and D. The Wistar rats were subjected to different doses of manganese chloride. The wistar rats in Group A were regarded as the Control which received only feed and distilled water daily for 29 days. Manganese chloride was administered at 10mg/kg, 20mg/kg and 30mg/kg orally to Group B, C and D respectively. The animals were sacrificed on day 30^th of the treatment by cervical dislocation. The brain was harvested, weighed with a sensitive weighing balance, Part of the brain was removed and homogenized for biochemical analysis for MDA (Malondialdehyde), NO (Nitric Oxide) and SDH (Succinate dehydrogenase) and the remaining parts were fixed in 10% formol calcium and was processed for histological analysis using H & E staining method.

The result showed that the mean body weights of the Wistar rats reduced significantly (P<0.05) in group B , C and D manganese chloride treated group compared with Group A .The brain weights in group B, C and D shows insignificant increase (P>0.05) when compared with group A (control group).The biochemical analysis result showed significant increase (P<0.05) in MDA (Malondialdehyde), NO (Nitric Oxide) and SDH( Succinate dehydrogenase) in the brain of manganese chloride treated groups compared to Control. The histological analysis indicated that occipital cortex shows observable degenerative changes in the occipital cortex characterized by peripheral and central degenerative changes, clustered pyknotic pyramidal and granule neurons that appear with fragmented cytoplasm and condensed nuclei in the manganese chloride treated compared with normal histoarchitecture of occipital cortex in the control.

The study concluded that Manganese Chloride treatment has adversely affected the occipital cortical tissue in the treated rats which may affect the occipital cortical functions.