Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Augusto Corrêa Street N. 01, Guamá, Belém, Pará, 66075-110, Brazil.
School of Dentistry, Institute of Health Sciences, Federal University of Pará, Belém, Brazil.
Biol Trace Elem Res. 2021 Oct;199(10):3707-3717. doi: 10.1007/s12011-020-02492-2. Epub 2021 Jan 6.
The alveolar bone is an important mineralized structure of the periodontal support apparatus, and information about the methylmercury (MeHg) effects on the structural integrity is scarce. Therefore, this study aimed to investigate whether systemic, chronic, and low-dose exposure to MeHg can change the alveolar bone microstructure of rats. Adult Wistar rats (n = 30) were exposed to 0.04 mg/kg/day of MeHg or vehicle through intragastric gavage. The animals were euthanized after 60 days, and blood samples were collected for trolox equivalent antioxidant capacity (TEAC), glutathione (GSH), lipid peroxidation (LPO), and comet assays. The mandible of each animal was collected and separated into hemimandibles that were used to determine the total Hg level in the bone and to analyze microstructural damage and alveolar bone loss in terms of trabecular number (Tb.N), trabecular thickness (Tb.Th), bone volume fraction (BV/TV), and exposed root area of the second molars. MeHg exposure triggered oxidative stress in blood represented by lower levels of GSH and TEAC and the increase in LPO and DNA damage of the blood cells. High total Hg levels were found in the alveolar bone, and the microstructural analyses showed a reduction in Tb.N, Tb.Th, and BV/TV, which resulted in an increase in the exposed root area and a decrease in bone height. Long-term MeHg exposure promotes a systemic redox imbalance associated with microstructural changes and alveolar bone loss and may indicate a potential risk indicator for periodontal diseases.
牙槽骨是牙周支持组织的重要矿化结构，关于甲基汞（MeHg）对其结构完整性影响的信息还很缺乏。因此，本研究旨在探讨系统性、慢性和低剂量的 MeHg 暴露是否会改变大鼠的牙槽骨微观结构。成年 Wistar 大鼠（n=30）通过灌胃接受 0.04mg/kg/天的 MeHg 或载体。60 天后，动物被安乐死，采集血液样本用于测定 Trolox 当量抗氧化能力（TEAC）、谷胱甘肽（GSH）、脂质过氧化（LPO）和彗星试验。收集每个动物的下颌骨并分离为半下颌骨，用于测定骨中的总 Hg 水平，并分析微结构损伤和牙槽骨丢失，包括骨小梁数量（Tb.N）、骨小梁厚度（Tb.Th）、骨体积分数（BV/TV）和第二磨牙暴露根面积。MeHg 暴露会引发血液中的氧化应激，表现为 GSH 和 TEAC 水平降低，LPO 增加和血细胞 DNA 损伤。在牙槽骨中发现了高总 Hg 水平，微观结构分析显示 Tb.N、Tb.Th 和 BV/TV 减少，导致暴露根面积增加和骨高度降低。长期 MeHg 暴露会导致系统性氧化还原失衡，与微结构变化和牙槽骨丢失有关，这可能表明牙周病的潜在风险指标。
