Effects of Pinealectomy and Gonadectomy on Olfactory Bulb Dopaminergic Neurons in Rats

Background: Olfactory disorder is an early manifestation of Parkinson's disease (PD), likely to be associated with abnormalities of the dopaminergic neurons in the olfactory bulb (OB); however, the causes of olfactory disorder in PD are not entirely clear. Some studies showed that melatonin (MT...

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Main Authors: Yan Li, Jian Zhu, Ying Wang, Lei Guo, Lei Li, Dong Wang
Format: Article
Language:English
Published: Wolters Kluwer 2017-01-01
Series:Chinese Medical Journal
Subjects:
Online Access:http://www.cmj.org/article.asp?issn=0366-6999;year=2017;volume=130;issue=19;spage=2302;epage=2306;aulast=Li
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author Yan Li
Jian Zhu
Ying Wang
Lei Guo
Lei Li
Dong Wang
author_facet Yan Li
Jian Zhu
Ying Wang
Lei Guo
Lei Li
Dong Wang
author_sort Yan Li
collection DOAJ
description Background: Olfactory disorder is an early manifestation of Parkinson's disease (PD), likely to be associated with abnormalities of the dopaminergic neurons in the olfactory bulb (OB); however, the causes of olfactory disorder in PD are not entirely clear. Some studies showed that melatonin (MT) and androgens (mainly testosterone, T) might participate in the pathogenesis of PD. The research aimed to investigate effects of MT or T deficiency on OB dopaminergic neurons in rats. Methods: One hundred and twenty normal male Wistar rats were randomly divided into the control, sham operation pinealectomy (PX), sham operation gonadectomy (GDX), PX, GDX, and PX + GDX groups. After 60 days, glial cell hyperplasia and neuronal apoptosis were examined with hematoxylin and eosin and the TUNEL method; the expression levels of tyrosine hydroxylase (TH), Bax, and Bcl-2 were measured using immunohistochemistry (IH) by the streptavidin peroxidase conjugated method. Comparison among multiple sets used analysis of variance and LSD method or Kruskal-Wallis test and Nemenyi method. Results: There were no significant differences between the sham operation groups and the control group; thus, they were merged into Group A. There was no significant glial cell hyperplasia (P > 0.05) or change in shape in any of the groups after PX or GDX. The number of apoptotic cells in Groups A (1.41 ± 0.56), PX (12.31 ± 4.68), GDX (20.52 ± 5.13), and PX + GDX (30.23 ± 5.25) successively significantly increased (P < 0.05). The number of TH (+) cells in Groups A (42.62 ± 5.63), PX (37.31 ± 4.32), GDX (31.07 ± 4.21), and PX + GDX (25.22 ± 3.66) was successively significantly decreased (P < 0.05). The gray value of TH (+) cells and fibers in Groups A (98.51 ± 10.36), PX (108.96 ± 13.01), GDX (119.02 ± 12.98), and PX + GDX (128.99 ± 13.39) was successively significantly increased (P < 0.05). The results of Bax staining were as follows: Group A+, Group PX++, Group GDX++, and Group PX+ GDX+++, the results of Bcl-2 in all groups were +. Conclusions: PX or GDX could lead to OB neurotoxicity in the following groups of rats in the following order: PX < GDX < PX + GDX. PX or GDX increased the ratio of Bax/Bcl-2. The effect of PX and GDX was equal, but both were less than that of PX + GDX. Neurotoxicity as a result of PX or GDX was not related to inflammation.
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spelling doaj.art-b30ebac1a3be4044b2a72fcf999205872022-12-21T23:49:17ZengWolters KluwerChinese Medical Journal0366-69992017-01-01130192302230610.4103/0366-6999.215336Effects of Pinealectomy and Gonadectomy on Olfactory Bulb Dopaminergic Neurons in RatsYan LiJian ZhuYing WangLei GuoLei LiDong WangBackground: Olfactory disorder is an early manifestation of Parkinson's disease (PD), likely to be associated with abnormalities of the dopaminergic neurons in the olfactory bulb (OB); however, the causes of olfactory disorder in PD are not entirely clear. Some studies showed that melatonin (MT) and androgens (mainly testosterone, T) might participate in the pathogenesis of PD. The research aimed to investigate effects of MT or T deficiency on OB dopaminergic neurons in rats. Methods: One hundred and twenty normal male Wistar rats were randomly divided into the control, sham operation pinealectomy (PX), sham operation gonadectomy (GDX), PX, GDX, and PX + GDX groups. After 60 days, glial cell hyperplasia and neuronal apoptosis were examined with hematoxylin and eosin and the TUNEL method; the expression levels of tyrosine hydroxylase (TH), Bax, and Bcl-2 were measured using immunohistochemistry (IH) by the streptavidin peroxidase conjugated method. Comparison among multiple sets used analysis of variance and LSD method or Kruskal-Wallis test and Nemenyi method. Results: There were no significant differences between the sham operation groups and the control group; thus, they were merged into Group A. There was no significant glial cell hyperplasia (P > 0.05) or change in shape in any of the groups after PX or GDX. The number of apoptotic cells in Groups A (1.41 ± 0.56), PX (12.31 ± 4.68), GDX (20.52 ± 5.13), and PX + GDX (30.23 ± 5.25) successively significantly increased (P < 0.05). The number of TH (+) cells in Groups A (42.62 ± 5.63), PX (37.31 ± 4.32), GDX (31.07 ± 4.21), and PX + GDX (25.22 ± 3.66) was successively significantly decreased (P < 0.05). The gray value of TH (+) cells and fibers in Groups A (98.51 ± 10.36), PX (108.96 ± 13.01), GDX (119.02 ± 12.98), and PX + GDX (128.99 ± 13.39) was successively significantly increased (P < 0.05). The results of Bax staining were as follows: Group A+, Group PX++, Group GDX++, and Group PX+ GDX+++, the results of Bcl-2 in all groups were +. Conclusions: PX or GDX could lead to OB neurotoxicity in the following groups of rats in the following order: PX < GDX < PX + GDX. PX or GDX increased the ratio of Bax/Bcl-2. The effect of PX and GDX was equal, but both were less than that of PX + GDX. Neurotoxicity as a result of PX or GDX was not related to inflammation.http://www.cmj.org/article.asp?issn=0366-6999;year=2017;volume=130;issue=19;spage=2302;epage=2306;aulast=LiApoptosis; Gonadectomy; Olfactory Bulb; Pinealectomy; Tyrosine Hydroxylase
spellingShingle Yan Li
Jian Zhu
Ying Wang
Lei Guo
Lei Li
Dong Wang
Effects of Pinealectomy and Gonadectomy on Olfactory Bulb Dopaminergic Neurons in Rats
Chinese Medical Journal
Apoptosis; Gonadectomy; Olfactory Bulb; Pinealectomy; Tyrosine Hydroxylase
title Effects of Pinealectomy and Gonadectomy on Olfactory Bulb Dopaminergic Neurons in Rats
title_full Effects of Pinealectomy and Gonadectomy on Olfactory Bulb Dopaminergic Neurons in Rats
title_fullStr Effects of Pinealectomy and Gonadectomy on Olfactory Bulb Dopaminergic Neurons in Rats
title_full_unstemmed Effects of Pinealectomy and Gonadectomy on Olfactory Bulb Dopaminergic Neurons in Rats
title_short Effects of Pinealectomy and Gonadectomy on Olfactory Bulb Dopaminergic Neurons in Rats
title_sort effects of pinealectomy and gonadectomy on olfactory bulb dopaminergic neurons in rats
topic Apoptosis; Gonadectomy; Olfactory Bulb; Pinealectomy; Tyrosine Hydroxylase
url http://www.cmj.org/article.asp?issn=0366-6999;year=2017;volume=130;issue=19;spage=2302;epage=2306;aulast=Li
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