The Role of High-Dose Vitamin A on the Amygdala of Adult Male Wistar Rats Exposed to Toxic Doses of Methamphetamine
Ezejindu Damian Nnabuihe
Department of Anatomy, Faculty of Basic Medical Sciences, Nnamdi Azikiwe University, Nnewi Campus, Anambra State, Nigeria.
Joshua Izuchukwu Abugu *
Department of Anatomy, Faculty of Basic Medical Sciences, Nnamdi Azikiwe University, Nnewi Campus, Anambra State, Nigeria and Department of Human Anatomy, Fculty of Basic Medical Sciences, State University of Medical and Applied Sciences, Igbo-Eno, Enugu State, Nigeria.
Enemuo Ijeoma
Department of Anatomy, Faculty of Basic Medical Sciences, Nnamdi Azikiwe University, Nnewi Campus, Anambra State, Nigeria.
Okeke Somadina Nnamdi
Department of Anatomy, Faculty of Basic Medical Sciences, Nnamdi Azikiwe University, Nnewi Campus, Anambra State, Nigeria.
Ogbuokiri Doris K
Department of Anatomy, Faculty of Basic Medical Sciences, Nnamdi Azikiwe University, Nnewi Campus, Anambra State, Nigeria.
Okeke Henry Kachikwuru
Department of Anatomy, Faculty of Basic Medical Sciences, Nnamdi Azikiwe University, Nnewi Campus, Anambra State, Nigeria.
Ekoh Augustine Alobu
Department of Anatomy, Faculty of Basic Medical Sciences, Nnamdi Azikiwe University, Nnewi Campus, Anambra State, Nigeria.
Benedict Nzube Obinwa
Department of Anatomy, Faculty of Basic Medical Sciences, Nnamdi Azikiwe University, Nnewi Campus, Anambra State, Nigeria.
Chinyere Elizabeth Eze
Department of Anatomy, Faculty of Basic Medical Sciences, Nnamdi Azikiwe University, Nnewi Campus, Anambra State, Nigeria.
Nwaefulu Kester Eluemunor
Department of Physiology, Faculty of Basic Medical Sciences, Nnamdi Azikiwe University, Nnewi Campus, Anambra State, Nigeria.
Sobanke A. Omolara
Department of Physiology, Faculty of Basic Medical Sciences, Nnamdi Azikiwe University, Nnewi Campus, Anambra State, Nigeria.
Chidinma Ifeyinwa Mmaju
Department of Physiology, Faculty of Basic Medical Sciences, Nnamdi Azikiwe University, Nnewi Campus, Anambra State, Nigeria.
Okafor Anulika Jacinta
Department of Physiology, Faculty of Basic Medical Sciences, Nnamdi Azikiwe University, Nnewi Campus, Anambra State, Nigeria.
Chuka-Onwuokwu Ngozi Cynthia
Department of Physiology, Faculty of Basic Medical Sciences, Nnamdi Azikiwe University, Nnewi Campus, Anambra State, Nigeria.
Ejiogu Ikedichukwu Chibueze
Department of Biochemistry, Faculty of Basic Medical Sciences, Nnamdi Azikiwe University, Nnewi Campus, Anambra State, Nigeria.
Nwoko Sebastine Okechukwu
Department of Biochemistry, Faculty of Basic Medical Sciences, Nnamdi Azikiwe University, Nnewi Campus, Anambra State, Nigeria.
Wuraola Serah Nnaemeka
Department of Biochemistry, Faculty of Basic Medical Sciences, Nnamdi Azikiwe University, Nnewi Campus, Anambra State, Nigeria.
Ebi Victory Chinecherem
Department of Medicine, College of Medicine, University of Calabar, Cross River State, Nigeria.
Agu Augustine Uchenna
Department of Anatomy, Faculty of Basic Medical Sciences, University of Nigeria, Enugu Campus, Enugu State, Nigeria.
Ugwu Augustus Uchenna
Department of Anatomy, Faculty of Basic Medical Sciences, University of Nigeria, Enugu Campus, Enugu State, Nigeria.
Nwodo Ndubuisi Francis
Department of Human Anatomy, Faculty of Basic Medical Sciences, Madonna University, Rivers State, Nigeria.
Elemuo Chukwuebuka Stanley
Department of Anatomy, Chukwuemeka Odumegwu Ojukwu University, Uli Campus, Anambra State, Nigeria.
Agbai Johnson Ukwa
Department of Human Anatomy, Faculty of Basic Medical Sciences, Abia State University, Uturu, Abia State, Nigeria.
Muorah Chinecherem Onyekachi
Department of Nursing science, Christopher University, Ogun State, Nigeria.
Ozoemena Chiadikobi Lawrence
Department of Human Anatomy, Fculty of Basic Medical Sciences, State University of Medical and Applied Sciences, Igbo-Eno, Enugu State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
The amygdala, a major limbic structure, regulates emotional response, anxiety, and memory formation. Methamphetamine is known to trigger oxidative stress and neurodegeneration, whereas vitamin A possesses potent antioxidant properties that may offer neuroprotection. This study evaluated the effect of high-dose vitamin A on the amygdala of adult male Wistar rats exposed to toxic doses of methamphetamine. Twenty (20) adults male Wistar rats were randomly assigned into four groups and received as follows: Group A (control), Group B (METH-only; 5 mg/kg at 3-hours interval within 12 hours in a day), group C (Vitamin A-only; 2.5 mg/kg), while, group D (combined METH 5 mg/kg at 3-hours interval within 12 hours in a day + Vitamin A-only; 2.5 mg/kg). All experimental groups received feed and water. The administration was done orally using intubation method for a period of twenty-eight days. Body weight result revealed a significant reduction in the methamphetamine-only group compared with the control suggesting metabolic disturbance and appetite suppression. Co-treatment with vitamin A improved body weight, indicating a restorative metabolic effect. Biochemical findings showed elevated malondialdehyde (MDA) and decreased glutathione (GSH) and superoxide dismutase (SOD) levels in the methamphetamine group, confirming oxidative damage within the amygdala. Vitamin A treatment markedly reduced MDA and preserved GSH and SOD activities, demonstrating enhanced antioxidant defense. Behavioral testing using the Elevated Plus Maze indicated anxiety-related alterations following methamphetamine exposure, while vitamin A co-administration protected these behavioral changes. Histological results showed that methamphetamine caused neuronal degeneration, vacuolation, and necrosis, whereas vitamin A preserved neuronal integrity and promoted partial structural recovery. In conclusion, high-dose vitamin A significantly mitigated methamphetamine-induced oxidative and structural damage in the amygdala, highlighting its antioxidative and neuroprotective potential against psychostimulant toxicity.
Keywords: Psychostimulant, vitamin A, amygdala, methamphetamine, neurodegeneration, neurotoxicity