| 陈辉宝,贾婷,张浩,王政昆,朱万龙.2022.外源褪黑激素通过调节摄食和产热降低大绒鼠的体重.动物学杂志,57(6):880-896. |
| 外源褪黑激素通过调节摄食和产热降低大绒鼠的体重 |
| Exogenous Melatonin Can Reduce Body Mass in Eothenomys miletus by Regulating Food Intake and Thermogenesis |
| 投稿时间：2022-04-09 修订日期：2022-11-23 |
| DOI：10.13859/j.cjz.202206008 |
| 中文关键词: 大绒鼠 褪黑激素 瘦素 褐色脂肪组织 产热 体重 |
| 英文关键词:Eothenomys miletus Melatonin Leptin Brown adipose tissue Thermogenesis Body mass |
| 基金项目:国家自然科学基金项目（No. 32160254），云南省中青年学术和技术带头人后备人才项目（No. 2019HB013），云南省万人计划青年拔尖人才项目（No. YNWR-QNRC-2019-047） |
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| 中文摘要: |
| 褪黑激素（MEL）是一种向动物传递光周期信息的分子，也参与能量稳态的调节。为探讨外源褪黑激素对大绒鼠（Eothenomys miletus）体重、能量代谢及体温调节的影响，将大绒鼠置于（25 ± 1）℃，光周期12 L∶12 D（白昼与黑夜各12 h）的环境中，每日腹腔注射褪黑激素（20 μg/kg），共28 d。结果发现，注射外源性褪黑激素后，大绒鼠的体重和摄食量显著降低，摄水量增加；核心体温和肩胛间皮肤温度显著升高；静止代谢率（RMR）和非颤抖性产热（NST）显著升高；肝和褐色脂肪组织（BAT）中的线粒体蛋白含量、细胞色素c氧化酶（COX）活性升高；褐色脂肪组织中的总蛋白、解偶联蛋白1（UCP1）、α-磷酸甘油氧化酶（α-PGO）、T45′-脱碘酶（T45′-DII）活性显著升高，但对肝总蛋白和α-PGO无显著影响；血清中瘦素、三碘甲腺原氨酸（T3）浓度显著上升，甲状腺素（T4）浓度显著降低。此外，注射褪黑激素后大绒鼠睾丸重量显著降低，表明其导致大绒鼠性腺退化。相关分析表明，解偶联蛋白1含量和三碘甲腺原氨酸浓度呈正相关，T45′-脱碘酶活性和三碘甲腺原氨酸含量呈正相关，暗示T45′-脱碘酶可能在褪黑激素诱导褐色脂肪组织产热中起重要作用。总之，外源褪黑激素可能通过抑制摄食和增加产热降低了大绒鼠的体重。 |
| 英文摘要: |
| [Objectives] Melatonin (MEL) is a molecule that conveys photoperiodic information in animals, which is also involved in the regulation of energy homeostasis. The present study aims to investigate the effects of exogenous melatonin on body mass, energy metabolism and thermoregulation in Eothenomys miletus. [Methods] E. miletus were placed at 25 ± 1 ℃ with a photoperiod of 12 L∶12 D (day and night 12 hours each) and received intraperitoneal injection of melatonin (20 μg/kg) daily for 28 days. Body mass, body temperature, food intake, water intake, thermogenic capacity and hormone concentrations were measured. Continuous changes in body temperature, food intake, water intake, resting metabolic rate (RMR) and nonshivering thermogenesis (NST) were measured by repeated measures covariance analysis (with body mass as a covariate). Body mass changes during acclimation were analyzed by repeated measurements, and body mass differences between groups were analyzed by independent sample t test. Differences of serum hormone contents, protein content in liver and brown adipose tissue (BAT), enzyme activity and other indicators between groups were analyzed by covariance analysis (with body mass as a covariate). The relationship between uncoupling protein 1 (UCP1) content, thyroxin 5′-deiodinase (T45′-DII) activity and serum triiodothyronine (T3) content was analyzed by Pearson correlation analysis. [Results] The results showed that exogenous melatonin injection significantly reduced body mass and food intake (Fig. 1a, Fig. 3a), while water intake increased (Fig. 3b). Core body temperature and interscapular skin temperature increased significantly (Fig. 1b, Fig. 2), resting metabolic rate and nonshivering thermogenesis also increased significantly (Fig. 4a, Fig. 4b). Mitochondrial protein content and cytochrome c oxidase (COX) activity in liver and brown adipose tissue increased, there were also significant increases in total protein in brown adipose tissue, uncoupling protein 1, α-glycerophosphate oxidase (α-PGO) and thyroxin 5’-deiodinase activities, but there were no significant effects on total liver protein or α-glycerophosphate oxidase in liver. Serum concentrations of leptin and triiodothyronine were significantly increased, while thyroxine (T4) was significantly decreased. Moreover, testicular mass was significantly reduced after melatonin injection (Table 2), suggesting that melatonin caused gonadal degeneration in E. miletus. Correlation analysis showed a positive correlation between uncoupling protein 1 content and triiodothyronine concentration (Fig. 5a), and a positive correlation between thyroxin 5′-deiodinase activity and triiodothyronine content (Fig. 5b), suggesting that thyroxin 5’-deiodinase may play an important role in the melatonin-induced thermogenesis of brown adipose tissue. [Conclusion] In conclusion, exogenous melatonin may reduce body mass in E. miletus by inhibiting feeding and increasing thermogenesis. |
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