The Effect of 1,25-Dihydroxyvitamin D3 on Dopaminergic Neurons and Microglial Activation in Parkinsonian Rat Model Induced by 6-Hydroxydopamine

J Korean Neurol Assoc > Volume 23(3); 2005 > Article

Journal of the Korean Neurological Association 2005;23(3): 368-373.

6-Hydroxydopamine으로 유발된 파킨슨 흰쥐 모델에서 비타민 D3가 도파민성 신경세포와 미세아교세포의 활성화에 미치는 영향

류선영, 김중석 최영빈 한시령 박정욱 박성경 김영인

가톨릭대학교 의과대학 신경과학교실

The Effect of 1,25-Dihydroxyvitamin D3 on Dopaminergic Neurons and Microglial Activation in Parkinsonian Rat Model Induced by 6-Hydroxydopamine

Seon-Young Ryu

Department of Neurology, The Catholic University of Korea College of Medicine, Seoul, Korea

Abstract

Background: Recent studies have shown increasing evidence for microglial activation in neuronal degeneration in Parkinson’s disease (PD), although the cause of PD remains unclear. Recent studies have also shown that 1α, 25-dihydroxyvitamin D3 (vitamin D3) exert neuroprotective effects by inducing an increased expression of neurotrophic factors, suggesting the possibility of vitamin D3 for the treatment of PD and other neurodegenerative diseases. The purpose of this study was to investigate the effect of vitamin D3 on 6-hydroxydopamine (6-OHDA)- induced neurotoxicity and microglial activation in adult rats.
Methods: Adult male Sprague-Dawley rats were subcutaneously injected with vitamin D3 or 0.1% ethanol for seven consecutive days and then infused unilaterally with 6-OHDA in the medial forebrain bundle. After 7 days of injection with 6-OHDA, the substantia nigra was examined by immunohistochemistry.
Results: The number of tyrosine hydroxylase (TH)-positive neurons in the lesioned substantia nigra pars compacta of vitamin D3 and ethanol groups was 84.8±18.84 and 52.6±13.23, respectively, fewer than that of the contralateral side (122.35±9.79 and 123.81±12.11, respectively) (P<0.05). The vitamin D3 group showed significantly higher numbers of the TH-positive neurons than that of the ethanol group (P<0.05). CD11b-positive microglial immunoreactivity was stronger in the lesion side than that of the normal side, and it was much weaker in the vitamin D3 group than that of the ethanol group (P<0.05).
Conclusions: These results indicate that vitamin D3 protects dopaminergic neurons from the neuronal injury induced by 6-OHDA, possibly by the mechanism involving microglial activation.KeyWords:Vitamin D3, Microglia, Parkinson's disease, 6-hydroxydopamine