Protective effects of vitamin D on neurophysiologic alterations in brain aging: role of brain-derived neurotrophic factor (BDNF)

ABSTRACT

Background/aim: Vitamin D has been hypothesized to be main regulator of the aging rate, alongside evidences support its role in neuroprotection. However, data about the protective role of vitamin D against neurophysiologic alterations associated with brain aging is limited. This study investigated the possible protective effects that vitamin D has on brain-derived neurotrophic factor (BDNF), cholinergic function, oxidative stress and apoptosis in aging rat brain.

Methods: Male Wister albino rats aged 5 months (young), 12 months (middle aged) and 24 months (old) (n = 20 each) were used. Each age group subdivided to either vitamin D3 supplementation (500 IU/kg/day orally for 5 weeks) or no supplementation (control) group (n = 10 each). Serum 25-hydroxyvitamin D [25(OH)D], brain BDNF and malondialdehyde levels and activities of acetylcholinesterase (AChE), antioxidant enzymes (glutathione reductase, glutathione peroxidase and superoxide dismutase) and caspase-3 were quantified.

Results: Vitamin D supplementation significantly mitigated the observed aging-related reduction in brain BDNF level and activities of AChE and antioxidant enzymes and elevation in malondialdehyde level and caspase-3 activity compared to control groups. Brain BDNF level correlated positively with serum 25(OH) D level and brain AChE activity and negatively with brain malondialdehyde level and caspase-3 activity in supplemented groups.

Conclusion: Restoring vitamin D levels may, therefore, represent a useful strategy for healthy brain aging. Augmenting brain BDNF seems to be a key mechanism through which vitamin D counteracts age-related brain dysfunction.

KEYWORDS:

• Brain aging
• neurophysiologic alterations
• neuroprotection
• vitamin D supplementation
• BDNF

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Notes on contributors

Eman Y. Khairy

Eman Y. Khairy is a lecturer of physiology in the physiology department, Medical Research Institute, Alexandria University, Egypt. She got the Bachelor of Medicine, Bachelor of Surgery (MBBCH) from the Faculty of Medicine, Alexandria University, Egypt. She earned her PhD in clinical physiology from the Medical Research Institute, Alexandria University, Egypt. She is interested in the field of neurophysiology and respiratory physiology.

Maha M. Attia

Maha M. Attia is a professor of physiology in the physiology department, Medical Research Institute, Alexandria University, Egypt. She got the Bachelor of Science from the Faculty of Science, Alexandria University, Egypt. She earned her PhD in physiology from the Faculty of Science, Alexandria University, Egypt. She is interested in the field of neurophysiology and endocrinology.