Leukocyte Populations of the Adult Rat Testis Following Removal of the Leydig Cells by Treatment With Ethane Dimethane Sulfonate and Subcutaneous Testosterone Implants1

Abstract

The influence of the Leydig cells on the leukocyte population of the testis was investigated. Leydig cells were destroyed by ethane dimethane sulfonate (EDS) treatment in adult male rats, with or without low-dose s.c. testosterone implants to prevent Leydig cell recovery. Leukocytes were counted in perfusion-fixed frozen testis sections, by use of cell-specific monoclonal antibodies (mAbs) with immunoperoxidase detection, or toluidine blue staining. The majority (81%) of testicular leukocytes (OX1+) were immunopositive for the resident macrophage-specific mAb, ED2, and/or the monocyte/macrophage/dendritic cell mAb, ED1. The remaining leukocytes were principally T lymphocytes (R73+). B lymphocytes (OX33+) and metachromatic mast cells were not observed in the normal testis. Treatment with EDS caused a transient increase in ED1+, ED2+, and R73+ cell numbers in the testis, although other evidence of an inflammatory reaction, such as increases in major histocompatibility complex class II antigen, interleukin-2 receptor expression, or capillary permeability, were not observed. At 21 days after EDS treatment, there was a significant decline in macrophage numbers (to approximately 50% of control testis), and T lymphocytes returned to pretreatment levels. After Leydig cell recovery (41 days after treatment), macrophages also returned to pretreatment levels in EDS-treated rats, but remained reduced in EDS-treated animals with testosterone implants. In addition, EDS treatment stimulated a progressive increase in intertubular mast cells, which was significantly inhibited in the testosterone-implanted rats. The data indicate that numbers of testicular macrophages and mast cells, but not of lymphocytes, within the adult rat testis are directly or indirectly regulated by the Leydig cells.

Cytokine profiles in the testes of rats treated with lipopolysaccharide reveal localized suppression of inflammatory responses

“…The volume densities of macrophages in the rat liver and testis, as determined by stereological and other analysis, are similar (6,35,68). Although there is some evidence that the liver itself possesses a degree of immunological protection against graft rejection, based on the relative success rates for transplantation of this organ (9), it is nonetheless clear that the proinflammatory response of the testis is severely compromised relative to the liver.…”

“…The testicular artery on one side was clamped, and the ipsilateral testis was collected, snap-frozen, and stored at Ϫ70°C for protein extraction. The remaining testis was perfused with saline by whole-body perfusion via the descending aorta, followed by periodate-lysine-paraformaldehyde fixative (ϳ10 -15 min), as previously described (68). The perfused testis was collected, postfixed in periodate-lysine-paraformaldehyde solution for a further 3 h, followed by immersion at 4°C in 7% sucrose for 36 h, then snap-frozen in liquid nitrogen, and embedded in Optimal Cutting Temperature (OCT) compound (Tissue-TEK, Elkhart, IN).…”

“…Rats (12/ treatment group) were injected (ip) with ethane dimethane sulfonate (EDS; 75 mg/kg body wt) dissolved in dimethyl sulfoxide (DMSO)/ water (1:3) to ablate the Leydig cells or DMSO/water alone (carrier control) as previously described (34,68). Ten days later, one-half of the rats in each group were injected (ip) with pyrogen-free saline (controls), and the remaining animals were injected with 0.1 mg LPS/kg body wt.…”

Testosterone Replacement Effectively Inhibits the Development of Experimental Autoimmune Orchitis in Rats: Evidence for a Direct Role of Testosterone on Regulatory T Cell Expansion

“…In our study, the administration of T3 implant as expected resulted in the reduction of serum gonadotropin levels below those necessary to sustain spermatogenesis. In contrast, the higher-dose T24 implants cause supraphysiological serum concentrations and resulted in sufficient levels (10-40% of normal testicular levels) to support qualitatively normal seminiferous tubule function (40,45,46). The histological assessment of the treated animals clearly showed that testosterone replacement provided a significant degree of protection against the development of orchitis with only 17% of EAO+T3 and 33% of EAO+ T24 animals developing the disease, compared with 80% when no hormone intervention was performed.…”

“…In contrast, high-dose T24 similarly causes a drop in LH, but supplies sufficient testosterone to maintain intratesticular T levels adequate to support qualitatively normal seminiferous tubule function (38,40).…”