Neuroprotective effects of estrogen on nigral dopaminergic neurons in the midbrains of rats with Parkinson disease

Xuewen TIAN; Xiang ZHANG; Jianning ZHANG; Xiling WANG

ABSTRACT

BACKGROUND:

There have been reports at home and abroad about effects of estrogen upon the dopamine amount in substantia nigra in the midbrains while the neuroprotective effects of estrogen are still being studied.

OBJECTIVE:

To observe the effects of estrogen on dopaminergic neurons and explore the feasibility of preventing and treating Parkinson disease with estrogen.

DESIGN:

A randomized controlled study based on the experimental animals.

SETTING:

General neurosurgery institute in a hospital of a military medical university of Chinese PLA.MATERIALS The trial was conducted in the General Neurosurgery Institute of Xijing Hospital,the Fourth Military Medical University of Chinese PLA from October 2003 to February 2004 with 50 healthy,first-grade Wistar rats as subjects.

INTERVENTIONS:

The rats were randomly assigned into 5 groups with 10in each group. Group 1 was normal control,group 2 sham-operation group,and groups 3,4,5 were ovariectomy groups. In group 3,10 μg of estradiol was administered twice a day ineach rat after ovariectomy. Each rat in group 4 was administered with estrogen antagonist,5 μg tamoxifen twice a day as well as estrogen. In group 5,only ovariectomy was performed. After stereotaxic injection of 6-hydroxydopamin into substantia nigra in the midbrains,the TH positive neurons were labeled and counted with immunohistochemic method and the rat's behavior was observed.MIAN OUTCOME

MEASURES:

①the circles of rat's rotation provoked by apomorphine.②the TH positive neuron count in the middrains of rat's substantia nigra 30 days after ovariectomy.

RESULTS:

Baseline characteristics among the groups were no difference ( P ＞ 0.05). The result of group 3 was different from that of group 5 ( P＜ 0.05 ). The result of group 4 was also different from that of group 3 and group 5 (P ＜ 0.05) . The TH positive neuron count in the midbrains ingroup 3 also differed from that in other groups( P ＜ 0.05).

CONCLUSION:

Estrogen acts as a neuroprotectant of the nigral dopaminergic neurons in the midbrains not only through estrogen receptor-dependent pathways but probably also through others.