Expression levels of Bax, Bcl-2 and brain-derived neurotrophic factor in the rat brain motor cortex after over fatigue-induced sudden death

doi:10.3969/j.issn.2095-4344.2016.49.012

Abstract

Abstract:

BACKGROUND: Exercise-induced sudden death is a common phenomenon during exercising, but the mechanism is not fully understood.
OBJECTIVE: To investigate the morphological changes of motor cortex and the expression levels of Bax, Bcl-2 and brain-derived neurotrophic factor (BDNF), and to explore the occurrence and regulatory mechanism of exercise-induced sudden death during the training of continuously exhaustive loaded-swimming.
METHODS: Seven selected from 130 male Sprague-Dawley rats were randomly as blank control group and the remaining rats were modeled into over fatigue, followed by continuously exhaustive loaded-swimming with the training cycle of 36 hours. Then seven rats were killed as groups 1, 2 and 3 at 6, 9, 12 and 36 hours of exhaustive loaded-swimming and all dead rats in near several experiments in the same model without choking water in each training or within 24 hours after the 6th 36 hours of training as exercise-induced sudden death group (n=5). The morphological changes of motor cortex were observed by hematoxylin-eosin staining, and the expression levels of Bax and Bcl-2 proteins and BDNF were examined by immunohistochemistry.
RESULTS AND CONCLUSION: (1) Compared with the blank control group, the morphology of motro cortex changed significantly, and the expression levels of Bax and Bcl-2 proteins and BDNF in the groups 1, 2, and 3 and exercise-induced sudden death group were significantly up-regulated (P < 0.05). (2) Moreover, in the groups 1, 2, and 3 and exercise-induced sudden death group, the expression levels of Bax and Bcl-2 proteins showed an increasing trend, especially Bcl-2; while, the expression level of BDNF increased firstly and then decreased. (3) In conclusion, the enhanced expression levels of Bax and Bcl-2 proteins and BDNF in brain motor cortex of fatigue and exercise-induced sudden death groups maybe related to the protection-inhibition mechanism. The reduced expression of BDNF in brain motor cortex may be one of the reasons inducing sudden death during over fatigue.

中国组织工程研究杂志出版内容重点：肾移植；肝移植；移植；心脏移植；组织移植；皮肤移植；皮瓣移植；血管移植；器官移植；组织工程

Key words: Models, Animal, Death, Sudden, Motor Cortex, Brain-Derived Neurotrophic Factor, Tissue Engineering

CLC Number:

R318

Yang Ren-jun, Yin Wei-yao, Li Hua. Expression levels of Bax, Bcl-2 and brain-derived neurotrophic factor in the rat brain motor cortex after over fatigue-induced sudden death[J]. Chinese Journal of Tissue Engineering Research, 2016, 20(49): 7377-7383.

Figures/Tables 2

2.1 实验动物数量分析实验为系统研究，相同实验模型重复了多次。本次实验动物数量为130只，用于本文研究的动物组数5组共33只，其中运动性猝死组为在4次系统研究中相同实验模型实验过程中收集到的偶然出现的死亡大鼠(排除溺水死亡)共5只。 2.2 模型创新性模型的创新在于用连续大强度的负重游泳训练模拟运动员或体育锻炼者过度训练的状态，并将多次实验过程中偶然出现的运动性猝死大鼠收集，检测相应指标并与过度疲劳状态下训练大鼠相应指标的变化进行比较，分析其差异，探讨运动性猝死发生的可能机制。 2.3 模型稳定性本模型为连续力竭性负重游泳训练的系统研究，整个实验过程模拟的是人在疲劳后连续进行大强度训练造成过度疲劳状态即过度训练，从开始训练到过度训练过程模型可重复多次进行，实验的重复性稳定性高，但运动性猝死案例是偶然发生，这更接近人类运动性猝死发生的现状。 2.4 大脑运动皮质苏木精-伊红染色结果空白对照组大脑运动皮质神经元排列整齐，细胞间质呈现为致密均匀，未见异常；力竭运动1组部分切片可见脑膜充血，其余未见异常；力竭运动2组运动皮质神经元排列出现错乱，运动皮质内微血管极度扩张；力竭运动3组运动皮质神经元排列出现错乱，运动皮质内微血管极度扩张，部分神经纤维缠绕，部分神经元红色变性且部分大鼠可见血管套现象；运动性猝死组大脑运动皮质神经元排列错乱，细胞间质疏松，部分神经元红色变性，出现大量空泡，运动皮质内微血管极度扩张，神经纤维缠绕，部分神经元自溶明显，见图1。 2.5 Bax蛋白免疫组化染色结果 Bax蛋白在空白对照组运动皮质中表达较弱，在力竭运动1，2，3组与运动性猝死组表达明显增高(P < 0.05)。但是力竭运动1，2，3组与运动性猝死组之间差异无显著性意义(P > 0.05)。且Bax蛋白在空白对照组、力竭运动1，2，3组、运动性猝死组的表达呈递增趋势，见图2及表2。"

References

[1] Drory Y. Exertion sudden death in soldiers. Med Sci Sport Exerc. 1991;23(2):147-151.
[2] 殷劲,蒋丽,刘钦龙.超量恢复的运动生理研究进展[M]. 成都:电子科技大学出版社, 2012:47-53.
[3] 殷劲,岳建兴,周进,等.糖酵解供能运动后“超量恢复区间”的研究[J].成都体育学院学报,2007,33(4):88-91.
[4] 殷劲,蒋丽,刘钦龙.超量恢复的运动生理研究进展[M]. 成都:电子科技大学出版社, 2012:87-95.
[5] 诸葛启钏.大鼠脑立体定位图谱[M].北京:人民卫生出版社, 2005:71-79.
[6] 陈昱,任秀琪.运动预处理对力竭运动大鼠大脑皮质GFAP表达的影响[J].北京体育大学学报,2010,33(10): 52-54.
[7] Borechert GM, Lanier W, Davidson BL. RNA polymerase III transcribes human MicroRNAs. Nat Struct Mol Biol. 2006;13(12):1097-1101.
[8] 王东,李洪滋.运动性猝死、过劳死41例统计分析及对策研究[J].吉林体育学院学报,2010,26(2):93-94.
[9] 王来栓,邵肖梅.线粒体与缺氧缺血性脑细胞凋亡[J].国外医学:脑血管疾病分册,2003,11(1):65-67.
[10] Husain K, Somani SM. Response of cardiac antioxidant system to alcohol and exercise training in the rat. Alcohol. 1997;14(3):301-307.
[11] 魏翠兰,袁琼嘉.运动预处理对力竭运动后大脑皮质微结构与自由基代谢的影响[J].山东体育学院学报,2012,28(5): 55-61.
[12] 代朋乙,黄昌林.中频脉冲电流经皮刺激运动性疲劳士兵肝区对GSH-PX、SOD、T-AOC活性及MDA含量的影响[J].解放军医学杂志,2014,39(3):245-248.
[13] Yoshiha S, Abe K, Basto R, et al. Influence of trainsient ischemia on lipidsoluble antioxidants,free fatty acid and energy metabolites in rat brain. Brain Res.1982;2(5): 245-307.
[14] 张海英.浅谈运动对细胞凋亡影响的研究进展[J].赤峰学院学报:自然科学版,2004,24(5):35-36.
[15] 陆阿明,陆爱云,夏春林.急性力竭运动对中枢神经系统细胞凋亡的影响[J].体育与科学,2007,28(2):62-65.
[16] 王瑞元.运动生理学[M].北京:人民体育出版社,2002:307.
[17] Korsmeyer SJ, Shutter JR, Veis DJ, at al. Bc-l 2/Bax: a rheostat that regulates an antioxidant pathway and cell death. Semin Cancer Biol.1993;4(6): 327-332.
[18] Sulejczak D, Czarkowska-Bauch J, Macias M, et al. Bcl-2 and Bax proteins are increased in neocortical but not in thalamic apoptosis following devascularizing lesion of the cerebral cortex in the rat: an immunohistochemical study. Brain Res.2004;1006(2):133-135.
[19] 王璐,邓文骞,袁琼嘉.运动预处理对力竭运动诱导的大鼠大脑皮质细胞凋亡的影响[J].中国运动医学杂志,2012,31(7)：602-606.
[20] Kim DH, Zhao X. BDNF protects neurons following injury by modulation of caspase activity. Neurocrit Care. 2005; 3(1):71-76.
[21] 赵波,汤海玲,但齐琴,等.脑损伤大鼠运动皮质BDNF的表达变化[J].四川大学学报(医学版),2012,43(2):236-239.