Mode of migration of normal lymphocytes inside murine testis

Abstract

Background: Previous studies have shown that in murine experimental autoimmune orchitis (EAO), lymphocytes preferably infiltrate into (1) the testicular capsule near the rete testis, (2) the subcapsular interstitium away from the rete testis, and (3) the interstitium surrounding the tubuli recti and rete testis. Therefore, these three sites might provide tissue environments in which specific lymphocytes can easily gain access to testicular autoantigens. However, there is another possibility that infiltrating lymphocytes in the testis spontaneously accumulate at these three sites via the lymphatic flow inside this organ during EAO.Methods: To examine this possibility, normal lymphocytes were locally injected into the peripheral testis regions of recipient mice. Testes were then collected at various times for investigating the chronological pattern of lymphocytic migration inside the testes at a light microscopic level.Results: The injected lymphocytes first stayed in the lymphatic space around the seminiferous tubules and then moved to the subcapsular lymphatic space away from the rete testis. The lymphocytes accumulated under the testicular capsule and then gradually infiltrated into the adjacent capsular tissue. In the capsule, the cells surrounded the arteriolae and then accumulated in the capsular tissue near the rete testis. Thereafter, the cells finally left the testes through the lymphatics running in the spermatic cords. In the course of the lymphocytic drainage, it was noted that the injected lymphocytes appeared not to pass through the testicular interstitium around the tubuli recti and rete testis.Conclusions: The regional distributions of the testicular lymphocytes imply that the lymphatic flow in the testis may somewhat influence murine EAO pathology characterized by lymphocytic accumulation in (1) the testicular capsule near the rete testis and (2) the subcapsular interstitium away from the rete testis. However, the pathology exhibiting lymphocytic accumulation in (3) the interstitium around the tubuli recti and rete testis is independent on the intratesticular lymph flow. Anat. Rec. 251:152-160, 1998.

The Origin of Lymphatic Capillaries in Murine Testes

“…A previous study showed that lymphocytes locally injected into the testis were preferably accumulated in the subcapsular lymphatic space away from the rete testis before migration into the tunica albuginea (Itoh et al, 1998b). The present study newly clarified that the lymphocytes drain into LYVE‐1‐positive lymphatic vessels in and just beneath the tunica albuginea.…”

“…It was also found that the seminiferous tubules in the testis are known to be bathed in a sea of lymph (Setchell, 1970a,b). Furthermore, the lymphocytes gathered in the tunica albuginea adjacent to the rete testis when normal lymphocytes were injected locally into the testes of recipient mice (Itoh et al, 1998b). However, the exact distribution of lymphatic capillaries in the testis has remained unclear.…”