Quantity Rather Than Quality in Teratospermic Males: A Histomorphometric and Flow Cytometric Evaluation of Spermatogenesis in the Domestic Cat (Felis catus)1

Abstract

Teratozoospermia (ejaculation of <40% morphologically normal sperm) commonly occurs within the Felidae, including certain domestic cats, but the cellular and molecular mechanisms that give rise to this phenomenon remain unknown. This study quantified spermatogenesis to identify differential dysfunctions in teratospermic versus normospermic (>60% normal sperm/ejaculate) domestic cats. Sperm used were from electroejaculates and cauda epididymides. Testes from 10 normo- and 10 teratospermic males were obtained by castration and then evaluated by histomorphometry, flow cytometry, and testicular testosterone enzyme immunoassay. Some morphometric traits (tubular diameter, epithelium height, interstitial area, number of Leydig cells, and blood vessels per cross-section) as well as testicular testosterone concentrations were similar between groups, but testicular volume was greater in teratospermic males. Stage frequencies differed also between both cat populations, suggesting possible dysfunctions in spermiation. Quantification of cell populations in most frequent stages revealed more spermatogenic cells and fewer Sertoli cells per tubule cross-section as well as per tissue unit in teratospermic donors. Hence, the ratio of spermatogenic cells per Sertoli cell was elevated in the teratospermic cat. DNA flow cytometry confirmed higher total spermatogenic and meiotic transformations in teratospermic males. In summary, compared with normospermic counterparts, teratospermic cats have a higher sperm output achieved by more sperm-producing tissue, more germ cells per Sertoli cell, and reduced germ cell loss during spermatogenesis. Gains in sperm quantity are produced at the expense of sperm quality.

Reproductive traits in captive and free-ranging males of the critically endangered Iberian lynx (Lynx pardinus)

“…It has been claimed that an increase in the proportion of abnormal spermatozoa is associated with an increase in sperm numbers in teratospermic cats (Neubauer et al 2004) but we have not found a significant association between these traits in the Iberian lynx. Iberian lynx reproductive traits, especially the low percentage of normal spermatozoa, and low circulating testosterone levels, may be related to low levels of genetic variability seen in this species, which is among the lowest documented for a felid species (Johnson et al 2004).…”

Unexpected requirement for a binding partner of the syntaxin family in phagocytosis by murine testicular Sertoli cells

“…An interesting study describes that teratospermic cats have a higher sperm output achieved by more GCs per SC, and reduced GC loss during spermatogenesis. 34 In this regard, stabilization of sperm quantity in Txlna siRNA-treated testis may be produced at the expense of sperm quality, such as motility and morphology. Although apoptosis usually serves to remove unwanted or potentially dangerous cells, there are some examples where apoptosis-like events do not lead to death but rather the unique differentiation of certain cell types.…”

Aspectos histológicos e morfométricos dos testículos de gatos domésticos (Felis catus)

“…As mensurações para os diâmetros dos túbulos seminíferos dos autores, foram maiores do que as mensurações encontradas nessa pesquisa. Neubauer et al (2004), no entanto, encontraram mensurações mais aproximadas aos nossos achados.…”