We previously established an immunological infertility model, experimental autoimmune orchitis (EAO), which can be induced by two subcutaneous injections of viable syngeneic testicular germ cells on days 0 and 14 in mice without using any adjuvant. In this EAO model, CD4+ T-cell-dependent lymphocytic infiltration and immune deposits were found with spermatogenic disturbance on day 120. However, the late stage of EAO (= postactive inflammation stage on day 365) has not yet been investigated. Therefore, we investigated the histopathological characteristics of the late stage. The results revealed that the lymphocytic infiltration finally resolved; however, the seminiferous epithelium persistently showed maturation arrest and the Sertoli cell-only feature. In the seminiferous tubules showing maturation arrest, both proliferation and apoptosis of germ cells had occurred simultaneously. It was also noted that there were deposits of immunoglobulin G and the third component of complement on the thickened basement membrane of seminiferous tubules in the late stage of EAO. These results indicate that histopathology after active inflammation in EAO comprises persistent damage to the seminiferous epithelium and may resemble the histopathology of "idiopathic disturbance of spermatogenesis" in man.
Immunization of mice with viable syngeneic testicular germ cells (TGC) alone can induce autoimmune responses against autoantigens of both round and elongating spermatids, resulting in the development of experimental autoimmune orchitis (EAO). Histological lesions in this EAO model without an adjuvant are characterized by lymphocytic infiltration into the testes, spermatogenic disturbance, and a complete lack of epididymitis. In this study, we investigated the effects of vasectomy (Vx) on TGC-induced EAO expecting that Vx augments the severity of testicular inflammation in A/J mice. The results showed that mice receiving Vx alone exhibited no significant inflammatory cell response in either the testes or epididymides, and mice receiving shamVxCTGC immunization had EAO with no epididymitis. In sharp contrast, no EAO was found in the testes of any mice receiving VxCTGC immunization. Instead, caput epididymitis involving CD4CT cells, CD8CT cells, B cells, and macrophages were induced in them with striking elevation of the tissue levels of both IL6 and IL10 mRNA. Furthermore, serum autoantibodies induced by shamVxCTGC immunization were reactive with both round (immature) and elongating (mature) spermatids; however, those induced by VxCTGC immunization were specific to acrosomes of mature spermatids and spermatozoa. These unexpected results indicate that Vx may induce the mode by which autoreactive lymphocytes gain access to TGC autoantigens in the epididymides, leading to autoimmune responses against the autoantigens of mature rather than immature spermatids. Reproduction (2008) 135 859-866
Abstract. Experimental autoimmune orchitis (EAO) is one of the models of immunological male infertility. Murine EAO is CD4+T cell-dependent and classically induced by immunization with a testicular homogenate and adjuvants. We previously established that immunization with viable syngeneic testicular germ cells (TGC) can also induce murine EAO with no use of any adjuvant. Analyses of this EAO model have already revealed that cultured spleen cells of immunized mice secreted interferon (IFN)-γ and that treatment of the immunized mice with anti-IFN-γ monoclonal antibodies significantly suppressed the EAO. It is known that both IFN-γ and tumor necrosis factor (TNF)-α are representative cytokines of Th1 cells and exhibit local toxicity toward the seminiferous epithelium in vivo. However, changes in these two cytokines in EAO-affected testes have not yet been investigated. Therefore, in the present study, we investigated the expression of intratesticular IFN-γ and TNF-α mRNAs in TGC-induced EAO using real-time RT-PCR. The results demonstrated that the intratesticular mRNAs for both IFN-γ and TNF-α significantly increased, while other cytokines such as IL-1α, IL-1β, IL-6 and TGF-β did not show dramatic changes in the immunized mice. These results suggest that secretion of significant amounts of IFN-γ and TNF-α in situ contributes to the spermatogenic disturbance in EAO. Key words: Autoimmunity, Cytokine, Spermatogenic disturbance, Testis (J. Reprod. Dev. 57: [296][297][298][299][300][301][302] 2011) xperimental autoimmune orchitis (EAO) is a model of immunologic inflammation leading to male infertility [1]. The histopathology is characterized by intratesticular infiltration of CD4+T cells, CD8+T cells, B cells and plasma cells, followed by spermatogenic disturbance [2,3]. Classically, immunization with a testicular homogenate (TH) emulsified in complete Freund's adjuvant (CFA) followed by intravenous injections of Bordetella pertussis (BP) is necessary for induction of EAO in mice [4,5]. TH+CFA+BP-induced EAO in mice is dependent on CD4+ T cells that secrete tumor necrosis factor (TNF)-α and interferon (IFN)-γ in vitro [6]. It has also been reported that the disease can be suppressed in vivo by the administration of anti-TNF-α antibodies but not anti-IFN-γ antibodies [6]. In rat EAO induced by immunization with TH+CFA+BP, it was shown that isolated testicular macrophages secreted both . However, the intratesticular changes in IFN-γ and TNF-α mRNA expression at the organ level have not yet been investigated in any EAO model.We previously established that two subcutaneous injections of viable syngeneic testicular germ cells (TGC) can induce CD4+ T cell-dependent EAO in both A/J and C3H/He mice with a very high incidence [2,10]. This model is unique in that CFA and BP are not necessary for EAO induction. However, in spite of no use of these adjuvants, it was found that delayed type hypersensitivity rather than humoral immunity against TGC antigens is critical for induction of the disease [2,11,12]. It was also shown tha...
Exposure to di-(2-ethylhexyl) phthalate (DEHP) has been reported to induce spermatogenic disturbance through oxidant stress and affect the immune system as an adjuvant. However, the effect of DEHP on the testicular immune microenvironment has not yet been investigated. In the present study, we examined the testicular immune microenvironment after exposure to doses of DEHP, previously identified as no-observed-adverse-effect levels. Adult male mice were administered food containing 0%, 0.01% or 0.1% DEHP and then testes were analyzed. The results showed that a slight but significant spermatogenic disturbance appeared in the 0.1% DEHP group but not in the 0.01% DEHP group at 8 weeks. It was also demonstrated that lymphocytes and F4/80- and MHC class II- positive cells were significantly increased with the elevation of IL-10 and IFN-γ mRNA expressions in the testes of not only the 0.1% DEHP group but also the 0.01% DEHP group at 8 weeks. Histochemical analyses involving horseradish peroxidase (HRP) as a tracer showed that a little blood-borne HRP had infiltrated into the lumen of a few seminiferous tubules beyond the blood-testis-barrier in both the 0.1% and 0.01% DEHP groups at 8 weeks. This indicates that a dose of DEHP that has little effects on spermatogenesis can change the testicular immune microenvironment with functional damage of the blood-testis barrier.
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