Mast cell numbers negatively correlate with fibrosis in cryptorchid testes

Mast Cells in the Mammalian Testis and Epididymis-Animal Models and Detection Methods

Mast cells (MCs) are an evolutionary well-conserved type of cells, mediating and modulating allergic responses in innate immunity and tissue remodeling after chronic inflammation. Among other tissues, they inhabit both the testis and epididymis. In the testis, MCs usually appear in the interstitial compartment in humans, but not in other standard experimental models, like rats and mice. MCs seem to be responsible for testicular tissue fibrosis in different causes of infertility. Although experimental animal models follow the effect on MC activation or penetration to the interstitial tissue like in humans to some extent, there is an inconsistency in the available literature regarding experimental design, animal strain, and detection methods used. This comprehensive review offers an insight into the literature on MCs in mammalian testes and epididymides. We aimed to find the most suitable model for research on MC and offer recommendations for future experimental designs. When using in vivo animal models, tunica albuginea incorporation and standard histological assessment need to be included. Domesticated boar strains kept in modified controlled conditions exhibit the highest similarity to the MC distribution in the human testis. 3D testicular models are promising but need further fine-tuning to become a valid model for MC investigation.

The role of ketotifen in the prevention of testicular damage in rats with experimental unilateral undescended testes

The aims of this study conducted on rats were to determine mast cell (MC) proliferation on undescended testes (UDTs); whether there is a correlation between MC proliferation and testicular damage; and whether testicular damage can be prevented with administration of an MC blocker. Sixty-five newborn male rats were divided into three groups. During the neonatal period, unilateral UDTs were experimentally induced in Group 2 and Group 3. The rats in Group 3 were given 1 mg/kg/day ketotifen orally until the end of the study. Groups 2 (n=30) and 3 (n=15) were divided into groups of ten and five rats, respectively, each of which underwent bilateral orchiectomy in either the prepubertal, pubertal, or adult period. Group 1 (n=15) underwent a sham operation followed by bilateral orchiectomy, with five rats in each of the prepubertal, pubertal, and adult periods. Testicular MCs in the interstitial and subtubular areas, biopsy scores, interstitial connective tissue, seminiferous tubule (ST) diameters, and the basement membrane thickness of STs were evaluated. In Group 2 the ST diameters in the UDTs decreased, the number of MCs in the interstitial and subtubular areas increased, ST basement membranes thickened, and spermatogenesis decreased. The number of MCs in the interstitial and subtubular areas of the descended testes increased and spermatogenesis decreased. In Group 3, the number of MCs in the interstitial and subtubular areas decreased. In unilateral UDTs, the number of MCs in the interstitial and subtubular areas increased in both testes. Fibrosis developed in the ST basement membranes and interstitial areas, and spermatogenesis deteriorated. Testicular fibrosis may be prevented with administration of an MC blocker.