Langheinrich A C, Paradowska A, Kilinski R, Kampschulte M, Steinfeld K, Altinkilic B, Steger K, Stieger P, Bergmann M, Weidner W
Department of Radiology, Justus Liebig University of Giessen, Giessen, Germany.
Int J Androl. 2012 Aug;35(4):562-71. doi: 10.1111/j.1365-2605.2011.01228.x. Epub 2011 Dec 13.
Age-related testicular changes are associated with declining spermatogenesis and testosterone levels. A relationship to atherosclerosis has never been investigated systematically. The ApoE(-/-)/LDL receptor(-/-) double knockout mouse model, providing a remarkable homology to human atherosclerosis, is an ideal tool to investigate spermatogenetic alterations in this context. Testes (n = 10) from ApoE(-/-)/LDL receptor(-/-) double knockout mice at the age of 80 weeks were perfused in vivo with contrast agent, harvested and scanned with micro-CT at (4.9 μm³) voxel size. Testes (n = 8) of C57/BL mice at the same age served as controls. Testis volume (mm³) and total vascular volume fraction (mm³) were quantified using micro-CT. Serum testosterone levels were determined. Testicular histology and epididymal sections were analysed for tubular structure, spermatogenetic scores and sperm count. The expression of protamine 2 as a marker for elongated spermatids, inflammation markers (CD4, F4/80) and hypoxia inducible factor 1 alpha (HIF1 alpha) were investigated using immunohistochemistry. ApoE(-/-)/LDL receptor(-/-) double knockout mice exhibit diminished testis and vascular volume fraction with respect to that of controls (p < 0.001). These findings were associated with a reduction of testosterone levels (p < 0.001). Mixed atrophy was present in 41% of the seminiferous tubuli in ApoE(-/-)/LDL receptor(-/-) double knockout mice at the age of 80 weeks. Sperm counts from the epididymis demonstrated a significant decrease in ApoE(-/-)/LDL receptor(-/-) double knockout mice (p < 0.001). In addition, sperm specific protamine 2 expression was decreased in testicular tissue and epididymis of ApoE(-/-)/LDL receptor(-/-) double knockout mice compared with that of control mice. Peritubular inflammatory infiltration and the expression of the hypoxia related marker was observed. Mixed testicular atrophy in ApoE(-/-)/LDL receptor(-/-) double knockout mice is linked to reduced testis volume, vascular volume fraction and low testosterone serum levels, suggesting a direct relation between atherosclerosis and disturbed spermatogenesis.
与年龄相关的睾丸变化与精子发生减少和睾酮水平下降有关。此前从未系统研究过其与动脉粥样硬化的关系。ApoE(-/-)/低密度脂蛋白受体(-/-)双敲除小鼠模型与人类动脉粥样硬化具有显著的同源性，是研究这种情况下精子发生改变的理想工具。对80周龄的ApoE(-/-)/低密度脂蛋白受体(-/-)双敲除小鼠的睾丸（n = 10）进行体内造影剂灌注，然后收获并以体素大小为(4.9μm³)进行显微CT扫描。相同年龄的C57/BL小鼠的睾丸（n = 8）作为对照。使用显微CT对睾丸体积（mm³）和总血管体积分数（mm³）进行定量。测定血清睾酮水平。对睾丸组织学和附睾切片进行分析，观察其管状结构、精子发生评分和精子计数。使用免疫组织化学研究鱼精蛋白2作为延长型精子细胞标志物的表达、炎症标志物（CD4、F4/80）和缺氧诱导因子1α（HIF1α）的表达。与对照组相比，ApoE(-/-)/低密度脂蛋白受体(-/-)双敲除小鼠的睾丸和血管体积分数减小（p < 0.001）。这些发现与睾酮水平降低相关（p < 0.001）。80周龄的ApoE(-/-)/低密度脂蛋白受体(-/-)双敲除小鼠中，41%的生精小管存在混合性萎缩。附睾精子计数显示，ApoE(-/-)/低密度脂蛋白受体(-/-)双敲除小鼠的精子数量显著减少（p < 0.001）。此外，与对照小鼠相比，ApoE(-/-)/低密度脂蛋白受体(-/-)双敲除小鼠的睾丸组织和附睾中精子特异性鱼精蛋白2的表达降低。观察到了生精小管周围的炎症浸润和缺氧相关标志物的表达。ApoE(-/-)/低密度脂蛋白受体(-/-)双敲除小鼠的混合性睾丸萎缩与睾丸体积减小、血管体积分数降低和血清睾酮水平低有关，提示动脉粥样硬化与精子发生障碍之间存在直接关系。
