Sato Yoko, Tharasanit Theerawat, Thitaram Chatchote, Somgird Chaleamchat, Mahasawangkul Sittidet, Thongtip Nikorn, Chatdarong Kaywalee, Tiptanavattana Narong, Taniguchi Masayasu, Otoi Takeshige, Techakumphu Mongkol
Department of Biology, School of Biological Sciences, Tokai University, Sapporo 0058601, Japan.
Department of Obstetrics, Gynaecology and Reproduction, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand.
Animals (Basel). 2024 Jul 30;14(15):2211. doi: 10.3390/ani14152211.
The abdominal testes of Asian elephants show normal spermatogenesis. Heat shock in cryptorchid testes elevates heat shock factor (HSF) expression, leading to germ cell apoptosis, while increased heat shock proteins (HSPs) levels provide protection. To investigate how heat shock affects elephant spermatogenic cells, focusing on heat shock-related molecules and the cell death mechanism, immunohistochemistry and TUNEL staining were employed to assess the immunoexpression of several heat shock-related molecules and the status of apoptosis in elephant fibroblasts (EF) induced by heat shock stimulus. Additionally, the immunoexpression of heat shock-related molecules and cell proliferation status in the elephant spermatogenic cells. Our finding indicated that heat shock-induced HSF1 immunoexpression in EF leads to apoptosis mediated by T-cell death-associated gene 51 (TDAG51) while also upregulating HSP70 to protect damaged cells. In elephant spermatogenic cells, immunostaining revealed a predominance of proliferating cell nuclear antigen (PCNA)-positive cells with minimal TDAG51- and TUNEL-positive cells, suggesting active proliferation and apoptosis suppression during normal spermatogenesis in the abdominal testis. Interestingly, spermatogonia co-immunoexpressed HSF1 and HSP90, potentially reducing apoptosis through protective mechanisms different from those observed in other mammals. Spermatogenic cells did not show immunolocalisation of HSP70, and hence, it may not contribute to protecting the spermatogonia from heat shock because the transcriptional activity of HSF1 is suppressed by HSP90A binding. This study provides insight into the specific heat shock response and defence mechanisms in elephant spermatogenic cells and may contribute to our understanding of species-specific adaptation to environmental stresses of the testis.
亚洲象的腹腔睾丸显示出正常的精子发生过程。隐睾中的热休克会提高热休克因子（HSF）的表达，导致生殖细胞凋亡，而热休克蛋白（HSPs）水平的升高则提供保护作用。为了研究热休克如何影响大象的生精细胞，重点关注热休克相关分子和细胞死亡机制，采用免疫组织化学和TUNEL染色来评估几种热休克相关分子的免疫表达以及热休克刺激诱导的大象成纤维细胞（EF）中的凋亡状态。此外，还研究了大象生精细胞中热休克相关分子的免疫表达和细胞增殖状态。我们的研究结果表明，热休克诱导的EF中HSF1免疫表达导致由T细胞死亡相关基因51（TDAG51）介导的凋亡，同时上调HSP70以保护受损细胞。在大象生精细胞中，免疫染色显示增殖细胞核抗原（PCNA）阳性细胞占主导，而TDAG51和TUNEL阳性细胞极少，这表明腹腔睾丸正常精子发生过程中细胞增殖活跃且凋亡受到抑制。有趣的是，精原细胞同时免疫表达HSF1和HSP90，可能通过与其他哺乳动物不同的保护机制减少凋亡。生精细胞未显示HSP70的免疫定位，因此，它可能无助于保护精原细胞免受热休克影响，因为HSP90A结合会抑制HSF1的转录活性。这项研究深入了解了大象生精细胞中的特定热休克反应和防御机制，可能有助于我们理解睾丸对环境压力的物种特异性适应。
