Mehraein Fereshteh, Talebi Reza, Jameie Behnamedin, Joghataie Mohammad Taghi, Madjd Zahra
Dept. of Anatomy, Tehran University of Medical Sciences, Hemmat Highway, Iran.
Arak University of Medical Sciences, Arak, Iran.
Iran Biomed J. 2011;15(1-2):44-50.
Melatonin has receptors in substantia nigra pars compacta (SNc) and regulates development of dopaminergic (DA) neurons. This study was undertaken to determine ability of melatonin to protect SNc dopaminergic neuron loss induced by estrogen deficiency in ovariectomized rats.
Female rats were randomized into four groups of seven each: control, ethanol sham, ovariectomy (ovx) and ovx with melatonin (ovx + m). In ovx, ovaries were removed. Ovx + m group was intraperitoneally injected with melatonin for 10 days, while the ethanol sham group received only ethanol. All rats were perfused with 4% paraformaldehyde, midbrains removed, fixed and paraffin embedded, then processed for Nissl and tyrosine hydroxylase staining (IHC). Ten sections of SNc in Nissl and IHC staining were analyzed in each animal, Nissl stained and tyrosine hydroxylase (TH) immunoreactive cells were counted in five experimental groups randomly. Data was analyzed using SPSS by ANOVA and t-test. Differences were considered significant for P<0.05.
There was less cell number in ovx compared to control and ethanol sham groups significantly (P<0.001). The ovx + m group had more cells than the ovx group in the SNc significantly (P<0.001). Furthermore, there was significant decrease of TH positive cell number in the ovx group compared to control and ethanol sham groups (P<0.05). The number of TH immunoreactive cells was higher in ovx + m compared to the ovx group (P<0.05).
These findings can be compared with human and used in clinical application for prevention of DA neuron death of SNc after ovariectomy.
褪黑素在黑质致密部（SNc）有受体，并调节多巴胺能（DA）神经元的发育。本研究旨在确定褪黑素保护去卵巢大鼠因雌激素缺乏引起的SNc多巴胺能神经元丢失的能力。
将雌性大鼠随机分为四组，每组7只：对照组、乙醇假手术组、去卵巢组（ovx）和去卵巢加褪黑素组（ovx + m）。ovx组切除卵巢。ovx + m组腹腔注射褪黑素10天，而乙醇假手术组仅接受乙醇。所有大鼠用4%多聚甲醛灌注，取出中脑，固定并石蜡包埋，然后进行尼氏染色和酪氨酸羟化酶染色（免疫组化）。对每只动物的SNc尼氏染色和免疫组化染色的10个切片进行分析，随机在五个实验组中计数尼氏染色和酪氨酸羟化酶（TH）免疫反应阳性细胞。使用SPSS通过方差分析和t检验分析数据。P<0.05时差异被认为具有统计学意义。
与对照组和乙醇假手术组相比，ovx组细胞数量明显减少（P<0.001）。ovx + m组SNc中的细胞比ovx组明显更多（P<0.001）。此外，与对照组和乙醇假手术组相比，ovx组TH阳性细胞数量明显减少（P<0.05）。ovx + m组TH免疫反应阳性细胞数量高于ovx组（P<0.05）。
这些发现可与人类情况进行比较，并用于临床预防去卵巢后SNc的DA神经元死亡。
