Examination of basement membrane components associated with the bovine seminiferous tubule basal lamina

Immunohistology has been used to examine the distribution of certain components of the basement membrane ( BM) associated with bovine spermatogonial germ cells that are located within the seminiferous tubules. Histology was performed on testis tissue from Brahman cattle (Bos indicus) of three different age groups: pre-pubescent (4-6 months), juvenile (8-10 months) and adult (18-24 months) animals. There were no major changes in the BM composition apparent between these three age groups, except for certain lectin staining. These data suggest that the predominant collagen type IV component may have an alpha 3 and alpha 4 composition, although other chains, including the alpha 5 and alpha 6 chains, were also present. Possibly the main laminin type present was laminin 121 (alpha 1 beta 2 gamma 1), although other variants were also present. Both nidogen-1 and perlecan, which are normal BM components, were also found as part of the seminiferous tubule BM. Interstitial collagens, such as type I, III and VI collagens, were found in the peritubular space, but were not part of the BM itself, although type VI collagen was most visible in the peritubular zone adjacent to the tubules. Examination of the BM with a range of lectins gave strong staining for(glcNAc)(2) entities, weak positive staining for alpha-L-fuc, but little or no staining for a-galNAc and ( glcNAc)(3) at all ages, whereas staining for alpha-gal, beta-gal(1 -> 3) galNAc and alpha-man showed developmental changes.