INVESTIGATING THE IMPACT OF EARLY MONOSODIUM L-GLUTAMATE EXPOSURE ON ORTHODONTIC AND SKELETAL MUSCLE DEVELOPMENT IN RAT MODELS: IMPLICATIONS FOR SPORTS MEDICINE

Authors

  • Xiaofang Cai Department of Stomatology, Minhang District Central Hospital Affiliated to Shanghai Fudan University, Shanghai 201100, China.
  • Min Cai Department of Integrative Medicine, Zhongshan Hospital, and Laboratory of Neurology, Institute of Integrative Medicine, Fudan University, Shanghai 200032, China.
  • Xiaoyu Zhao Department of Stomatology, Shanghai Institute of Medical Imaging, Zhongshan Hospital, Fudan University, Shanghai 200032, China.
  • Jun Xiang Department of Integrative Medicine, Zhongshan Hospital, and Laboratory of Neurology, Institute of Integrative Medicine, Fudan University, Shanghai 200032, China.
  • Feng Yang Department of Integrative Medicine, Zhongshan Hospital, and Laboratory of Neurology, Institute of Integrative Medicine, Fudan University, Shanghai 200032, China.
  • Wen Zhu Department of Integrative Medicine, Zhongshan Hospital, and Laboratory of Neurology, Institute of Integrative Medicine, Fudan University, Shanghai 200032, China.
  • Wei Bi Department of Stomatology, Shanghai Institute of Medical Imaging, Zhongshan Hospital, Fudan University, Shanghai 200032, China.
  • Xiaojun Ding Department of Stomatology, Shanghai Institute of Medical Imaging, Zhongshan Hospital, Fudan University, Shanghai 200032, China.

Keywords:

monosodium L-glutamate; sex hormone; orthodontic tooth movement; osteoprotegerin / NF-kappaB ligand

Abstract

This study investigates the impact of neonatal exposure to monosodium L-glutamate (MSG) on orthodontic and musculoskeletal development in rats, aiming to establish an animal model relevant to sports medicine. Neonatal rats received MSG injections to induce hypothalamic damage, hypothesized to disrupt the hypothalamic-pituitary-gonadal axis and influence sex hormone levels. Such hormonal imbalances are known to alter the osteoprotegerin/NF-kappaB ligand (OPG/RANKL) ratio, crucial for bone remodeling during orthodontic tooth movement and potentially affecting skeletal muscle development relevant to athletic performance. Design: The study administered MSG to neonatal rats, targeting the arcuate nucleus of the hypothalamus. We monitored sex hormone levels, pro-inflammatory cytokine expression, the OPG/RANKL ratio, osteoclast activity, and changes in alveolar bone morphology and tooth movement. These variables were compared between MSG-treated rats and a control (sham) group following orthodontic appliance activation. Results: MSG treatment resulted in suppressed hypothalamic-pituitary-adrenal axis function, enhanced osteoclast differentiation, increased alveolar bone resorption, and expanded periodontal space as revealed by micro-CT. There was also increased osteoblast activity on the tension side of the orthodontically moved teeth, altered cytokine levels, and a decreased OPG/RANKL ratio. Conclusions: Neonatal MSG injections disrupt several physiological pathways crucial for orthodontic tooth movement and bone integrity, potentially mirroring the skeletal muscle and bone challenges faced by athletes. This model sheds light on the complex interactions between endocrine health and musculoskeletal development, offering a novel perspective for sports medicine research. The findings underscore the need for further studies to explore therapeutic interventions that could mitigate the adverse effects of hormonal imbalances on physical health and athletic performance.

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Published

2023-02-21

Issue

Vol. 23 No. 90 (2023): Vol. 23, No. 90, junio / June 2023

Section

Manuscript