Neural Regeneration Research ›› 2018, Vol. 13 ›› Issue (2): 272-279.doi: 10.4103/1673-5374.220779

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Hyperhomocysteinemia induces injury in olfactory bulb neurons by downregulating Hes1 and Hes5 expression

Jing-wen Zhang1, 2, Bo Pang1, Qi Zhao1, Yue Chang1, Yi-li Wang2, Yi-deng Jiang1, Li Jing1   

  1. 1 School of Basic Medical Science, Ningxia Key Laboratory of Cerebrocranial Diseases-Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, Ningxia Hui Autonomous Region, China
    2 Institute of Immunopathology, Medical School, Key Laboratory of Biomedical Information Engineering of Ministry of Education, Xi’an Jiaotong University, Xi’an, Shaanxi Province, China
  • Received:2017-12-02 Online:2018-02-15 Published:2018-02-15
  • Contact: Yi-li Wang or Li Jing,wangyili@mail.xjtu.edu.cn or jingli@nxmu.edu.cn.
  • Supported by:

    This study was supported by the National Natural Science Foundation of China, No. 81560084, 81560208; a grant from the Project of Superior Discipline Groups in Ningxia Medical University of China, No. XY201414.

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Abstract:

Hyperhomocysteinemia has been shown to be associated with neurodegenerative diseases; however, lesions or histological changes and mechanisms underlying homocysteine-induced injury in olfactory bulb neurons remain unclear. In this study, hyperhomocysteinemia was induced in apolipoprotein E-deficient mice with 1.7% methionine. Pathological changes in the olfactory bulb were observed through hematoxylin-eosin and Pischingert staining. Cell apoptosis in the olfactory bulb was determined through terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining. Transmission electron microscopy revealed an abnormal ultrastructure of neurons. Furthermore, immunoreactivity and expression of the hairy enhancer of the split 1 (Hes1) and Hes5 were measured using immunohistochemistry, immunofluorescence, and western blot assay. Our results revealed no significant structural abnormality in the olfactory bulb of hyperhomocysteinemic mice. However, the number of TUNEL-positive cells increased in the olfactory bulb, lipofuscin and vacuolization were visible in mitochondria, and the expression of Hes1 and Hes5 decreased. These findings confirm that hyperhomocysteinemia induces injury in olfactory bulb neurons by downregulating Hes1 and Hes5 expression.

Key words: nerve regeneration, olfactory bulb, apoptosis, neurons, Nissl body, homocysteine, hairy enhancer of split 1, hairy enhancer of split 5, neural regeneration