Investigating the Effects of Methamphetamine on the Amygdala of Adult Male Wistar Rats

Abstract

Much attention has been drawn to the toxic effect of Methamphetamine in humans. However, it is not clear whether the toxicity is related to vital organs such as the brain. Hence, this work is geared towards unravelling the neurological & histological effects caused by Methamphetamine on the amygdala of adult Wistar rats. Twenty-four male Wistar rats were weighed and distributed into 4 groups of 6 animals each. Group A served as the control as they were administered feed & distilled water only; Group B was administered 3mg/kg body weight of Methamphetamine; Group C was administered 5mg/kg body weight of Methamphetamine while Group D was administered 10mg/kg body weight of Methamphetamine.  Methamphetamine was administered via oral mode of exposure for 21 days. Twenty-four hours after the last administration, the animals were anaesthetized under chloroform vapour and their skull was dissected by occipitofrontal incision. The brain tissue of some of the animals was prepared for biochemical analysis through the process of homogenization while the remaining brain tissues from some of the animals were harvested and fixed in 10% neutral buffered formalin for 48 hours and grossed to isolate the brain tissue of interest for histological investigation. There was a significant decrease in the body weight of animals in the experimental groups when compared to the control group.  Malondialdehyde (MDA) level was significantly higher (P<0.05) in the experimental groups when compared to the control group which increased oxidative stress. Whereas Glutathione (GSH) and superoxide dismutase (SOD) levels were significantly lower in the experimental groups when compared to the control group which also resulted in an increase in oxidative stress in the experimental groups. The histological observations showed that following the administration of Methamphetamine, there was moderate to severe degeneration with necrosis, severe aggregate and infiltration of inflammatory cells, severe granular cell hyperplasia and atrophy as well as a focal area of haemorrhage in the experimental groups. The result of this study shows that methamphetamine caused an adverse histological alteration on the amygdala of the Wistar rat. This alteration is dose dependent. Methamphetamine does not support brain health as distortion of brain tissue was revealed.