Vitamin D3 favorable outcome on recognition memory and prefrontal cortex expression of choline acetyltransferase and acetylcholinesterase in experimental model of chronic high-fat feeding

Cholecalciferol Supplementation Impacts Behavior and Hippocampal Neuroglial Reorganization in Vitamin D-Deficient Rats

Vitamin D deficiency (VDD) is widespread around the world and has been extensively documented to affect various health conditions, including the cognitive functioning of the brain. Serum 25-hydroxylated forms of vitamin D are traditionally used to determine vitamin D status. However, there is now evidence that cholecalciferol activation can occur and be controlled by locally expressed enzymes in the brain. This study aimed to investigate the effects of cholecalciferol supplementation on cognitive function in rats who underwent transient VDD in adulthood. Thirty-six adult Wistar rats were administered paricalcitol (seven doses of 32 ng injected every other day) along with a "vitamin D-free" diet to induce VDD, which was confirmed using a LC-MS/MS serum analysis of the cholecalciferol and 25-hydroxyvitamin D3 levels. Treatment was performed by including 1000 IU/kg and 10,000 IU/kg cholecalciferol in the diet. Cognitive performance was evaluated using the novel object recognition (NOR), Morris water maze (MWM), and radial arm maze (RAM) tests. An immunohistochemical analysis of the brain regions involved in learning and memory was performed by quantifying the neurons, astrocytes, and microglia labelled with anti-neuronal nuclei (NeuN), glial fibrillary acidic protein (GFAP), and ionized calcium-binding adaptor molecule 1 (Iba-1) antibodies, respectively. The vitamin D deficient group showed the lowest performance in both the MWM and RAM tests. In contrast, the cholecalciferol-treated groups exhibited a faster learning curve. However, no difference was detected between the groups in the NOR test. On the other hand, differences in the cellular organization of the hippocampus and amygdala were observed between the groups. Cholecalciferol supplementation decreased the density of the Iba-1- and GFAP-labeled cells in the hilus and cornu Ammonis 3 (CA3) regions of the hippocampus and in the amygdala. These results support vitamin D's substantial role in learning and memory. They also highlight that subtle changes of cognitive function induced by transient VDD could be reversed by cholecalciferol supplementation. Further studies are needed to better understand VDD and cholecalciferol's effects on the brain structure and function.

Molecular Regulation of the CNS by Vitamin D

Vitamin D is a lipid-soluble vitamin that can be found in some foods. It is also produced endogenously (in the presence of ultraviolet light), transported through the blood to the targets organs and this is the reason to consider vitamin D as a hormone. It is known that vitamin D has genomic and non-genomic effects. This review is focused mainly on the vitamin D receptors, the importance of vitamin D as a neuromodulator, the role of vitamin D in the pathophysiology of devastating neurological disorders such as Alzheimer's disease, multiple sclerosis, amyotrophic lateral sclerosis, Parkinson's disease and the benefit of vitamin D and its derivates in alleviating these disorders.

Vitamin D3 exerts immunomodulatory and memory improving properties in rats with lipopolysaccharide-induced inflammation

INTRODUCTION

Vitamin D is a fat-soluble secosteroid, its primary function being regulation of calcium-phosphate homeostasis and maintenance of bone integrity and mineralization. Recently, pleotropic effects of this vitamin have been recognized, including an immunomodulatory role and involvement in normal brain development and functioning.

Cognition enhancing abilities of vitamin D, epalrestat and their combination in diabetic rats with and without scopolamine induced amnesia

Persistent hyperglycaemia and scopolamine were used to inflict amnesia in rats. Chronic hyperglycaemia causes metabolic impairment, neuronal dysfunction and oxidative stress causing cognitive impairment. This study aimed to determine anti amnesic activities of vitamin D, epalrestat and their combination against diabetes and scopolamine induced cognitive dysfunction. A total of eighty-eight Wistar albino rats, eleven groups, and 8 rats/Gr., were used. Type 2 diabetes mellitus was induced in all groups, except Gr.1 which was treated with 2 ml normal saline. Gr. 2 to 11 by feeding high fat diet for 28 days followed by single dose streptozotocin 35 mg/kg i.p. Hyperglycemic rats were screened with blood sugar level > 200 mg/dL. Gr. 2 rats were treated with only streptozotocin and Gr. 3 to 6 were treated with streptozotocin and test drugs donepezil 1 mg/kg, vitamin D, 27 mcg/kg, epalrestat 57 mg/kg, vitamin D + epalrestat, per oral, respectively. Gr. 7 rats were treated with only streptozotocin + scopolamine and all others from Gr. 8 to 11 were treated with streptozotocin + scopolamine and donepezil, vitamin D, epalrestat, vitamin D + epalrestat respectively. The gold standard behavioural tests were conducted by using Morris water maze and passive avoidance paradigms after 30–60 min of inj. scopolamine, 0.5 mg/kg, intra-peritoneal. Hippocampal tissue was taken for histopathological and biochemical evaluation. Rats treated with donepezil, vitamin D, epalrestat and vitamin D + epalrestat showed significant improvement in behavioural, biochemical and histopathological parameters as compared to streptozotocin and (streptozotocin + scopolamine) treated rats. This study underscores cognition enhancing abilities of vitamin D and epalrestat, and their combination in diabetic rats with and without scopolamine.

Protective effects of vitamin D on learning and memory deficit induced by scopolamine in male rats: the roles of brain-derived neurotrophic factor and oxidative stress

The beneficial effects of vitamin D (vit D) on central nervous system disorders have been suggested. In the current research, the protective effects of vit D on learning and memory deficit induced by scopolamine, oxidative stress criteria, brain-derived neurotrophic factor (BDNF), and nitric oxide (NO) in the brain were investigated. Rats were divided into five groups, including (1) Control, (2) Scopolamine (2 mg/kg), (3-5) Scopolamine + Vit D (100, 1000, and 10,000 IU/kg) groups. Vit D administrated for 2 weeks and in the third week scopolamine co-administrated with vit D and behavioral tests, including Morris water maze (MWM) and passive avoidance (PA) tests, were carried out. The cortical and hippocampal tissues were analyzed for BDNF, catalase (CAT), and superoxide dismutase (SOD) activities, thiol content, NO metabolites, and malondialdehyde (MDA) concentration. Scopolamine injection significantly impaired rats' performance on the MWM and PA test. It further enhanced the MDA and nitrite level while decreased thiol content and BDNF levels and SOD and CAT activities in the brain. Administration of both 1000 and 10,000 IU/kg vit D improved cognitive outcome in MWM and PA tests. In addition, vit D elevated thiol content, SOD and CAT activities, and BDNF levels, while reduced nitrite and MDA concentration. Vit D also increased the levels of vit D and calcium in the serum. The results demonstrated that vit D has protective effects on scopolamine-associated learning and memory impairment by improving BDNF levels and attenuating NO and brain tissue oxidative damage.