ABSTRACT
<p><b>Objective</b>To study the expression of CLAUDIN-11 in the testis tissue of non-obstructive azoospermia (NOA) patients with different severities and investigate its clinical significance.</p><p><b>METHODS</b>Sixty-two NOA patients were divided into a hypospermatogenesis (HS) group (n = 30) and a Sertoli cell only syndrome (SCO) group (n =32). The expression of CLAUDIN-11 in the testicular tissue of the patients was detected by immunohistochemistry, that of CLAUDIN-11 mRNA determined by real-time fluorescence quantitative polymerase chain reaction (RT-qPCR), and the levels of serum reproductive hormones measured by chemiluminescent immunoassay.</p><p><b>RESULTS</b>Immunohistochemistry showed that the expression of CLAUDIN-11 was mainly in the cytoplasm of the Sertoli cells around the seminiferous tubule wall in the HS group, but diffusely distributed in the membrane of the Sertoli cells in the SCO group. RT-qPCR revealed a significantly lower expression of CLAUDIN-11 mRNA in the HS than in the SCO group (0.008 ± 0.001 vs 0.013 ± 0.002, t = 10.616, P<0.01). The level of serum luteotropic hormone (LH) was also markedly lower in the HS than in the SCO group (［3.62 ± 1.34］ vs ［4.96 ± 3.10］ IU/L, P<0.05) and so was that of follicle-stimulating hormone (FSH) (［5.36 ± 2.80］ vs ［10.65 ± 9.18］ IU/L, P<0.05).</p><p><b>CONCLUSIONS</b>The up-regulated expression of CLAUDIN-11 in Sertoli cells may play an important role in the development and progression of spermatogenic dysfunction in NOA patients.</p>
Subject(s)
Humans , Male , Azoospermia , Genetics , Metabolism , Claudins , Metabolism , Follicle Stimulating Hormone , Metabolism , Oligospermia , Genetics , Metabolism , RNA, Messenger , Metabolism , Seminiferous Tubules , Metabolism , Sertoli Cell-Only Syndrome , Genetics , Metabolism , Sertoli Cells , Metabolism , Spermatogenesis , Testis , MetabolismABSTRACT
The Sertoli cell tight junction (TJ) is the key component of the blood-testis barrier, where it sequesters developing germ cells undergoing spermatogenesis within the seminiferous tubules. Hormonally regulated claudin-11 is a critical transmembrane protein involved in barrier function and its murine knockout results in infertility. We aimed to assess quantitatively the significance of the contribution of claudin-11 to TJ function, in vitro, using siRNA-mediated gene silencing. We also conducted an analysis of the contribution of occludin, another intrinsic transmembrane protein of the TJ. Silencing of claudin-11 and/or occludin was conducted using siRNA in an immature rat Sertoli cell culture model. Transepithelial electrical resistance was used to assess quantitatively TJ function throughout the culture. Two days after siRNA treatment, cells were fixed for immunocytochemical localization of junction proteins or lyzed for RT-PCR assessment of mRNA expression. Silencing of claudin-11, occludin, or both resulted in significant decreases in TJ function of 55% (P < 0.01), 51% (P < 0.01), and 62% (P < 0.01), respectively. Data were concomitant with significant decreases in mRNA expression and marked reductions in the localization of targeted proteins to the Sertoli cell TJ. We provide quantitative evidence that claudin-11 contributes significantly (P < 0.01) to Sertoli cell TJ function in vitro. Interestingly, occludin, which is hormonally regulated but not implicated in infertility until late adulthood, is also a significant (P < 0.01) contributor to barrier function. Our data are consistent with in vivo studies that clearly demonstrate a role for these proteins in maintaining normal TJ barrier structure and function.
ABSTRACT
Objective To observe the effect of astragaloside IV (A) and SB203580 antagonize cadmium (Cd) toxicity on expression of associated protein and blood-testis barrier(BTB) in rats and to study the protective mechanism of A on it.Methods Totally 21 SD male rats were randomly divided into 7 groups, 3 rats per group:Cd [ intraperitoneally injected with 0.1%CdCl2,1mg/(kg?d)],Cd+A [at the above dose of CdCl2,at the same time with A,10mg/(kg?d)], and Cd +SB203580 [at the above dose of CdCl2,at the same time with SB203580,100μg/(kg?d)], each of the above groups was further divided into continuous five and ten days treatment groups .The control group was intraperitoneally injected with equal dosage of normal saline .The testes were studied by light , electron microscopy , immunohistochemistry and Western blotting .Results In the control group ,irregular and lightly stained nuclei of Sertoli cell ( Sc) in seminiferous tubules were observed by HE staining .A continuous electron density line of tight junction ( TJ) and normal ultrastructure of BTB were observed .After Cd treatment ,the vesicular formation in the Sc was observed .The ultrastructural damage of Sc and TJ was observed .Compared with the corresponding time point of Cd group ,these were weakened in morphology of testis and ultrastructure of TJ after Cd +A or Cd +SB203580 treatment .The positive products of zonula occludens-1 ( ZO-1 ) and claudin-11 were localized mainly in the base of the seminiferous tubule .After Cd treatment , the average absorbance (AA) of ZO-1 and Claudin-11 was decreased significantly compared with that of the control group (P<0.05).After Cd +A or Cd +SB203580 treatment,AA of ZO-1 and Claudin-11 were increased significantly compared with that of the Cd group(P<0.05),though lower than that of the control group .The result of Western blotting showed that phosphorylation-p38MAPK in Cd group was increased significantly compared with that of the control group (P<0.05).After Cd +A or Cd+SB203580 treatment, it was decreased significantly compared with that of the Cd group (P<0.05).Conclusion Cd decreases ZO-1 and Claudin-11 expression and damages ultrastructure of TJ in BTB , asⅣhas protective effect on it , and is related to inhibiting activation of p 38 MAPK pathway .