Richardson L L, Kleinman H K, Dym M
Department of Cell Biology, Georgetown University Medical Center, Washington, DC 20007, USA.
J Androl. 1995 Mar-Apr;16(2):118-26.
Age-related increases in basement membrane thickness have been noted in many tissues, including the testis. The current investigation examined the morphology of the basement membrane in the aged Brown Norway rat and sought to determine whether the accumulation of basement membrane was the result of an increase in the expression of the basement membrane genes. The aged testis was characterized by atrophy of the seminiferous tubules. Closer examination of the degenerated tubules revealed that the seminiferous epithelium was completely devoid of germ cells and that the basement membrane of these tubules was thickened and highly convoluted. In some animals, there was a measurable increase in basement membrane thickness in tubules of normal diameter together with an apparently normal epithelium, suggesting that the thickening is not solely due to a shrinkage of the tubules. To determine whether an increase in basement membrane synthesis was responsible for the thickening, the expression of the genes for laminin, collagen IV, heparan sulfate proteoglycan, and fibronectin was analyzed by Northern blot. There were no changes in the expression of the genes for the laminin B1 and B2 chains, heparan sulfate proteoglycan, or fibronectin that could be correlated with increasing age. Surprisingly, however, the levels of mRNA for the laminin A chain and collagen IV decreased with age.(ABSTRACT TRUNCATED AT 250 WORDS)
在包括睾丸在内的许多组织中，都已发现与年龄相关的基底膜厚度增加现象。本研究检测了老年棕色挪威大鼠基底膜的形态，并试图确定基底膜的增厚是否是基底膜基因表达增加的结果。老年睾丸的特征是生精小管萎缩。对退化小管的进一步检查发现，生精上皮完全没有生殖细胞，并且这些小管的基底膜增厚且高度卷曲。在一些动物中，直径正常的小管的基底膜厚度有可测量的增加，同时上皮似乎正常，这表明增厚并非仅仅是由于小管萎缩所致。为了确定基底膜合成增加是否是增厚的原因，通过Northern印迹法分析了层粘连蛋白、IV型胶原、硫酸乙酰肝素蛋白聚糖和纤连蛋白基因的表达。层粘连蛋白B1和B2链、硫酸乙酰肝素蛋白聚糖或纤连蛋白基因的表达没有变化，无法与年龄增长相关联。然而，令人惊讶的是，层粘连蛋白A链和IV型胶原的mRNA水平随年龄增长而下降。（摘要截短于250字）
