Liu Wanjing, Chen Chuanyue, Chen Liang, Wang Li, Li Jian, Chen Yuanyuan, Jin Jienan, Kawan Atufa, Zhang Xuezhen
College of Fisheries, Huazhong Agricultural University, Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan 430070, People's Republic of China.
Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, People's Republic of China.
Sci Rep. 2016 Mar 10;6:22819. doi: 10.1038/srep22819.
While microcystins (MCs) have been reported to exert reproductive toxicity on fish with a sex-dependent effect, the underlying mechanism has been rarely investigated. In the present study, zebrafish were exposed to 1, 5 and 20 μg/L MC-LR for 30 d. The gonad-somatic index declined in all treated males. 17β-estradiol (E2), testosterone (T), 11-keto testosterone (11-KT) and follicle-stimulating hormone (FSH) levels increased in serum from all treated females, while T, FSH and luteinizing hormone (LH) levels changed in all treated males. Histomorphological observation showed that MC-LR exposure evidently retarded oogenesis and spermatogenesis. Transcriptional changes of 22 genes of the hypothalamic-pituitary-gonad (HPG) axis exhibited sex-specific responses, and the relationship between gene transcriptions and gametogenesis was evaluated by principle component analysis (PCA). Major contributors to PC1 (gnrh2, gnrhr3, ar, lhr, hmgra, hmgrb and cyp19a) were positively correlated with the number of post-vitellogenic oocytes, while PC1 (gnrh2, lhβ, erβ, fshr, cyp11a and 17βhsd) were positively correlated with the number of spermatozoa. The protein levels of 17βHSD and CYP19a were affected in both females and males. In conclusion, this study first investigated the sex-dependent effects of microcystins on fish reproduction and revealed some important molecular biomarkers related to gametogenesis in zebrafish suffered from MC-LR.
虽然已有报道称微囊藻毒素（MCs）对鱼类具有生殖毒性且存在性别依赖性效应，但其潜在机制鲜有研究。在本研究中，斑马鱼分别暴露于1、5和20μg/L的MC-LR中30天。所有处理组的雄性斑马鱼性腺-体指数均下降。所有处理组的雌性斑马鱼血清中17β-雌二醇（E2）、睾酮（T）、11-酮睾酮（11-KT）和促卵泡激素（FSH）水平升高，而所有处理组的雄性斑马鱼T、FSH和促黄体生成素（LH）水平发生变化。组织形态学观察表明，暴露于MC-LR明显阻碍了卵子发生和精子发生。下丘脑-垂体-性腺（HPG）轴的22个基因的转录变化表现出性别特异性反应，并通过主成分分析（PCA）评估基因转录与配子发生之间的关系。PC1的主要贡献者（gnrh2、gnrhr3、ar、lhr、hmgra、hmgrb和cyp19a）与卵黄生成后期卵母细胞数量呈正相关，而PC1（gnrh2、lhβ、erβ、fshr、cyp11a和17βhsd）与精子数量呈正相关。雌性和雄性斑马鱼中17βHSD和CYP19a的蛋白水平均受到影响。总之，本研究首次调查了微囊藻毒素对鱼类繁殖的性别依赖性效应，并揭示了一些与遭受MC-LR的斑马鱼配子发生相关的重要分子生物标志物。
