季节性繁殖是野生动物广泛使用的繁殖策略,特别是居住在温带地区的脊椎动物。一般来说,环境温度被认为是影响动物生殖状况的重要因素。在本研究中,野生地松鼠(Spermophilusdauricus),典型的季节性育种者,被用作动物模型来研究低环境温度对睾丸功能的影响背后的机制。模拟野生地松鼠的冬季环境,我们将饲养环境中的温度梯度降低到4°C。取样时,在正常环境温度下饲养的松鼠的体表温度(22°C,NAT组)和低环境温度(4°C,LAT组)分别为31.5°C和22.8°C,分别。随后,我们进行了免疫组织化学检测,qPCR,和酶联免疫吸附测定(ELISA)来检查睾丸功能的变化,以及线粒体的动力学和功能,在NAT和LAT组的松鼠中。因此,PCNA免疫染色阳性水平,LAT组睾丸中P21和P27显著降低,而裂解的Caspase-3和TUNEL的免疫染色水平明显更高。此外,低温处理降低了类固醇生成相关基因的表达水平,包括LHR,FSHR,GATA-4,P450scc,和P450arom,并降低了睾酮浓度。此外,线粒体分裂和融合的标记,分别为DRP1和MFN2,在LAT组的睾丸中增加。此外,LAT组睾丸中SOD1的mRNA水平明显升高。总之,低温抑制精子发生,类固醇生成,以及野生地松鼠睾丸的线粒体动力学和功能。
Seasonal reproduction is a widely used breeding strategy in wildlife, especially vertebrates inhabiting temperate regions. Generally, ambient temperature is considered a significant factor influencing the reproductive status of animals. In the present study, wild ground squirrels (Spermophilus dauricus), typical seasonal breeders, were used as an animal model to investigate the mechanism behind the impact of low ambient temperature on testicular function. To simulate the winter environment of wild ground squirrels, we lowered the temperature gradient in the rearing environment to 4 °C. At sampling, the body surface temperature of the squirrels reared under normal ambient temperature (22 °C, NAT group) and the low ambient temperature (4 °C, LAT group) were 31.5 °C and 22.8 °C, respectively. Subsequently, we conducted immunohistochemical assays, qPCR, and enzyme-linked immunosorbent assays (ELISA) to examine the variations in testicular functions, as well as the dynamics and functions of mitochondria, in the squirrels of NAT and LAT groups. As a result, the levels of positive immunostaining for PCNA, P21, and P27 were significantly lower in the
testes of LAT group, while the levels of immunostaining for Cleaved Caspase-3 and TUNEL were significantly higher. In addition, the low-temperature treatment reduced the expression level of steroidogenesis-related genes, including LHR, FSHR, GATA-4, P450scc, and P450arom, and decreased the testosterone concentration. Moreover, markers of mitochondrial fission and fusion, DRP1 and MFN2, respectively, were increased in the
testes of LAT group. Additionally, the mRNA level of SOD1 was notably higher in the
testes of LAT group. In conclusion, the low ambient temperature inhibited spermatogenesis, steroidogenesis, as well as mitochondrial dynamics and functions in the
testes of wild ground squirrels.