Effect of Bacille-Calmette-Guerin vaccine against rotenone-induced Parkinson's disease: Role of neuroinflammation and neurotransmitters

Background: Parkinson's disease (PD) is an extrapyramidal movement disorder associated with a hypokinetic condition generated by impairment in dopaminergic neuronal viability in the nigrostriatal region of the brain. Current medications can only provide symptomatic management; to date, no permanent cure is available. To compensate for this lacuna, researchers are gaining interest in antigen-based therapy, and Bacille-Calmette-Guerin (BCG) is one of the vaccines with a high safety margin that acts by stimulating immunoreactive T-cells in the CNS and reducing expression of pro-inflammatory cytokines including interleukin (IL)-1 beta and tumor necrotic factor (TNF-alpha) to produce neuroprotection. A previous study reported that BCG exerts a neuroprotective effect against several neurodegenerative disorders, such as Alzheimer's disease.Objective: The objective of this study is to explore the neuroprotective effect of the BCG vaccine against the rotenone model of PD.Methods: Rotenone (1.5 mg/kg, s.c) for 28 days, and BCG vaccine (2 x 107 cfu, i.p) single dose was injected to rats, and behavioral assessments were performed on the 21st and 28th day. On the 29th day, rats were sacrificed, and brains were isolated for biochemical and neurochemical estimation.Results: BCG vaccine significantly restored rotenone-induced motor deficits (open field test, narrow beam walk, and rotarod), biochemical levels (GSH, SOD, catalase, MDA, and nitrite), neurotransmitters (dopamine, 5-hydroxy tryptamine, norepinephrine, 3,4-dihydroxyphenylacetic acid, hemovanillic acid, and 5-hydroxy indoleacetic acid), and levels of inflammatory cytokines (IL-1 beta and TNF-alpha) in the striatum. It also prevents histopathological changes by reducing eosinophilic lesions in the striatum.Conclusion: From the results, we conclude that BCG vaccine showed neuroprotection through antioxidant and anti-inflammatory effect. Thus, in the future, it can be used as a neuroprotective agent for other neurological disorders, including PD.

Automated summary

This study aimed to investigate the neuroprotective effect of the BCG vaccine on the rotenone-induced Parkinson's disease model. Rats were injected with rotenone and the BCG vaccine, and behavioral assessments and biochemical analysis were performed. The results showed that the BCG vaccine significantly improved motor deficits, restored biochemical levels, normalized neurotransmitter levels, and reduced inflammatory cytokines in the striatum. These findings suggest that the BCG vaccine has neuroprotective properties and could be used for other neurological disorders, including PD.