Sharma Anju, Kaninathan Arigesavan, Dahal Sumedha, Kumari Susmita, Choudhary Bibha, Raghavan Sathees C
Department of Biochemistry, Indian Institute of Science, Bangalore, India.
Institute of Bioinformatics and Applied Biotechnology, Bangalore, India.
Front Genet. 2022 Nov 24;13:1047746. doi: 10.3389/fgene.2022.1047746. eCollection 2022.
Increased infertility in humans is attributed to the increased use of environmental chemicals in the last several decades. Various studies have identified pesticides as one of the causes of reproductive toxicity. In a previous study, infertility was observed in male mice due to testicular atrophy and decreased sperm count when a sublethal dose of endosulfan (3 mg/kg) with a serum concentration of 23 μg/L was used. However, the serum concentration of endosulfan was much higher (up to 500 μg/L) in people living in endosulfan-exposed areas compared to the one used in the investigation. To mimic the situation in an experimental setup, mice were exposed to 5 mg/kg body weight of endosulfan, and reproductive toxicity and long-term impact on the general biology of animals were examined. HPLC analysis revealed a serum concentration of ∼50 μg/L of endosulfan after 24 h endosulfan exposure affected the normal physiology of mice. Histopathological studies suggest a persistent, severe effect on reproductive organs where vacuole degeneration of basal germinal epithelial cells and degradation of the interstitial matrix were observed in testes. Ovaries showed a reduction in the number of mature Graafian follicles. At the same time, mild vacuolation in liver hepatocytes and changes in the architecture of the lungs were observed. Endosulfan exposure induced DNA damage and mutations in germ cells at the molecular level. Interestingly, even after 8 months of endosulfan exposure, we observed increased DNA breaks in reproductive tissues. An increased DNA Ligase III expression was also observed, consistent with reported elevated levels of MMEJ-mediated repair. Further, we observed the generation of tumors in a few of the treated mice with time. Thus, the study not only explores the changes in the general biology of the mice upon exposure to endosulfan but also describes the molecular mechanism of its long-term effects.
人类不孕症增加归因于过去几十年环境化学物质使用的增加。各种研究已确定农药是生殖毒性的原因之一。在先前的一项研究中,当使用亚致死剂量(3毫克/千克)、血清浓度为23微克/升的硫丹时,雄性小鼠因睾丸萎缩和精子数量减少而出现不育。然而,与研究中使用的浓度相比,生活在硫丹暴露地区的人群血清中硫丹浓度要高得多(高达500微克/升)。为了在实验装置中模拟这种情况,让小鼠接触5毫克/千克体重的硫丹,并检测其生殖毒性以及对动物整体生物学的长期影响。高效液相色谱分析显示,硫丹暴露24小时后血清中硫丹浓度约为50微克/升,这影响了小鼠的正常生理。组织病理学研究表明,对生殖器官有持续、严重的影响,在睾丸中观察到基底生发上皮细胞的空泡变性和间质基质的降解。卵巢中成熟格拉夫卵泡数量减少。同时,观察到肝脏肝细胞有轻度空泡化以及肺部结构改变。硫丹暴露在分子水平上诱导生殖细胞中的DNA损伤和突变。有趣的是,即使在硫丹暴露8个月后,我们仍观察到生殖组织中的DNA断裂增加。还观察到DNA连接酶III表达增加,这与报道的微同源末端连接介导的修复水平升高一致。此外,随着时间的推移,我们在一些接受治疗的小鼠中观察到肿瘤的产生。因此,该研究不仅探讨了小鼠接触硫丹后整体生物学的变化,还描述了其长期影响的分子机制。