Yachiguchi Koji, Sekiguchi Toshio, Nakano Masaki, Hattori Atsuhiko, Yamamoto Megumi, Kitamura Kei-ichiro, Maeda Masahiro, Tabuchi Yoshiaki, Kondo Takashi, Kamauchi Hiromitsu, Nakabayashi Hajime, Srivastav Ajai K, Hayakawa Kazuichi, Sakamoto Tatsuya, Suzuki Nobuo
1 Noto Marine Laboratory, Institute of Nature and Environmental Technology, Kanazawa University, Housu-gun, Ishikawa 927-0553, Japan.
Zoolog Sci. 2014 May;31(5):330-7. doi: 10.2108/zs130265.
To evaluate the effects of inorganic mercury (InHg) and methylmercury (MeHg) on bone metabolism in a marine teleost, the activity of tartrate-resistant acid phosphatase (TRAP) and alkaline phosphatase (ALP) as indicators of such activity in osteoclasts and osteoblasts, respectively, were examined in scales of nibbler fish (Girella punctata). We found several lines of scales with nearly the same TRAP and ALP activity levels. Using these scales, we evaluated the influence of InHg and MeHg. TRAP activity in the scales treated with InHg (10(-5) and 10(-4) M) and MeHg (10(-6) to 10(-4) M) during 6 hrs of incubation decreased significantly. In contrast, ALP activity decreased after exposure to InHg (10(-5) and 10(-4) M) and MeHg (10(-6) to 10(-4) M) for 18 and 36 hrs, although its activity did not change after 6 hrs of incubation. As in enzyme activity 6 hrs after incubation, mRNA expression of TRAP (osteoclastic marker) decreased significantly with InHg and MeHg treatment, while that of collagen (osteoblastic marker) did not change significantly. At 6 hrs after incubation, the mRNA expression of metallothionein, which is a metal-binding protein in osteoblasts, was significantly increased following treatment with InHg or MeHg, suggesting that it may be involved in the protection of osteoblasts against mercury exposure up to 6 hrs after incubation. To our knowledge, this is the first report of the effects of mercury on osteoclasts and osteoblasts using marine teleost scale as a model system of bone.
为了评估无机汞（InHg）和甲基汞（MeHg）对海洋硬骨鱼骨骼代谢的影响，分别以抗酒石酸酸性磷酸酶（TRAP）和碱性磷酸酶（ALP）的活性作为破骨细胞和成骨细胞此类活性的指标，在日本黑鲷（Girella punctata）的鳞片中进行了检测。我们发现了几条TRAP和ALP活性水平几乎相同的鳞片。利用这些鳞片，我们评估了InHg和MeHg的影响。在孵育6小时期间，用InHg（10⁻⁵和10⁻⁴ M）和MeHg（10⁻⁶至10⁻⁴ M）处理的鳞片中的TRAP活性显著降低。相比之下，暴露于InHg（10⁻⁵和10⁻⁴ M）和MeHg（10⁻⁶至10⁻⁴ M）18和36小时后，ALP活性降低，尽管孵育6小时后其活性没有变化。与孵育6小时后的酶活性一样，TRAP（破骨细胞标志物）的mRNA表达在InHg和MeHg处理后显著降低，而胶原蛋白（成骨细胞标志物）的mRNA表达没有显著变化。在孵育6小时时，用InHg或MeHg处理后，成骨细胞中金属结合蛋白金属硫蛋白的mRNA表达显著增加，这表明它可能在孵育后6小时内参与保护成骨细胞免受汞暴露的影响。据我们所知，这是以海洋硬骨鱼鳞片作为骨骼模型系统，关于汞对破骨细胞和成骨细胞影响的首次报道。
