RESUMO
We have previously shown an inverse correlation between testicular melatonin concentration and inflammation/oxidative stress-related markers levels in infertile men showing unexplained azoospermia. Here, we evaluated the impact of melatonin oral supplementation (daily 3 mg dose used to treat sleep disorders) in the incidence of local inflammation, oxidative stress, and tubular wall fibrosis development in young and middle-aged infertile adult men. Compared with testes without histological alterations, gonads with morphological abnormalities showed lower melatonin concentration along with increased macrophage numbers, TBARS generation, and expression levels of inflammation-related markers and antioxidant enzymes, as well as tubular wall collagen fibers disorganization and thickening. Melatonin oral supplementation not only increased its own testicular levels but also decreased inflammation- and oxidative stress-related markers levels, and improved the tubular wall aspect. Overall, our work provides insights into the potential benefits of melatonin on the inflammatory and oxidative status in testes of patients suffering from unexplained infertility.
Assuntos
Inflamação/tratamento farmacológico , Melatonina/uso terapêutico , Estresse Oxidativo/efeitos dos fármacos , Espermatogênese/efeitos dos fármacos , Testículo/efeitos dos fármacos , Adulto , Antioxidantes/uso terapêutico , Suplementos Nutricionais , Humanos , MasculinoRESUMO
We have previously described that melatonin inhibits androgen production in hamster testes via melatonin subtype 1a (mel1a) receptors and the local corticotrophin-releasing hormone (CRH) system. This study attempted to determine the initial events of the melatonin/CRH signaling pathway. In Leydig cells from reproductively active Syrian hamsters, Western blotting, reverse transcription quantitative polymerase chain reaction (RT-qPCR) and a colorimetric assay demonstrated that melatonin and CRH activate tyrosine phosphatases and subsequently reduce the phosphorylation levels of extracellular signal-regulated kinase (erk) and c-jun N-terminal kinase (jnk), down-regulate the expression of c-jun, c-fos and steroidogenic acute regulatory (StAR), and inhibit the production of testosterone. These effects were prevented by a highly selective CRH antagonist, thus indicating that melatonin does not exert a direct role. Specific mitogen-activated protein kinase kinase (MEK) and jnk blockers inhibited expression of c-jun, c-fos, StAR and the production of testosterone, confirming that these are events triggered downstream of erk and jnk. In Leydig cells from photoperiodically regressed adult hamsters, CRH inhibited the production of androstane-3α,17ß-diol (3α-diol), the main androgen produced, through the same signaling pathway. Testicular melatonin concentration was 3-4-fold higher in reproductively inactive hamsters than that detected in active animals. Since melatonin, CRH, and their receptors are present not only in hamster testes but also in testicular biopsies of infertile men, we can conjecture about the relevance of this previously uncharacterized pathway in human fertility disorders. In summary, our study identifies crucial intracellular events triggered by melatonin/CRH in the testis that lead to a down-regulation of the steroidogenic process.
Assuntos
Hormônio Liberador da Corticotropina/metabolismo , Células Intersticiais do Testículo/metabolismo , Melatonina/metabolismo , Animais , Cricetinae , Masculino , Transdução de Sinais/fisiologiaRESUMO
BACKGROUND: In non-obstructive azoospermia, histological patterns of Sertoli cell-only Syndrome (SCO) and hypospermatogenesis (H) are commonly found. In these pathologies, Leydig cell hyperplasia (LCH) is detected in some patients. Since TGF-ß1 is involved in cellular proliferation/development, the aim of this work was to analyze the expression of TGF-ß1, its receptors TGFBRII, TGFBRI (ALK-1 and ALK-5), and the co-receptor endoglin in human biopsies from patients with idiopathic infertility. METHODS: Specific immunostaining of TGF-ß1, its receptors TGFBRII, TGFBRI (ALK-1 and ALK-5), co-receptor endoglin and Smads proteins, were carried out in testicular biopsies from normal and infertile men with SCO or H. Gene expression of TGF-ß1 system were made in biopsies from infertile patients with semi-quantitative and quantitative PCR. RESULTS: Immunohistochemical studies revealed that TGF-ß1 and its specific receptors are present in Leydig cells in biopsies from normal tissue or patients with SCO or H with or without LCH. Smad proteins, which are involved in TGF-ß1 signaling, are also detected in both their phosphorylated (activated) and dephosphorylated form in all samples TGF-ß1, ALK-1 and endoglin gene expression are stronger in human biopsies with LCH than in those with SCO or H. Neither TGFBRII nor ALK-5 gene expression showed significant differences between pathologies. A significant correlation between ALK-1 and endoglin expression was observed. CONCLUSIONS: In conclusion, the high levels of mRNA and protein expression of the TGF-ß1 system in patients with LCH, particularly ALK1 and its correlation with endoglin, suggest that these proteins acting in concert might be, at least in part, committed actors in the Leydig cell hyperplasia.
Assuntos
Infertilidade Masculina/metabolismo , Proteínas Serina-Treonina Quinases/biossíntese , Receptores de Fatores de Crescimento Transformadores beta/biossíntese , Síndrome de Células de Sertoli/metabolismo , Doenças Testiculares/metabolismo , Fator de Crescimento Transformador beta1/biossíntese , Receptores de Activinas Tipo II/biossíntese , Adulto , Antígenos CD/biossíntese , Endoglina , Humanos , Hiperplasia/metabolismo , Células Intersticiais do Testículo/metabolismo , Células Intersticiais do Testículo/patologia , Masculino , Pessoa de Meia-Idade , RNA Mensageiro/metabolismo , Receptor do Fator de Crescimento Transformador beta Tipo I , Receptor do Fator de Crescimento Transformador beta Tipo II , Receptores de Superfície Celular/biossíntese , Proteínas Smad/metabolismo , Testículo/metabolismoRESUMO
As we previously reported, testes of men suffering from hypospermatogenesis and germ cell arrest or Sertoli cell-only syndrome show a major increase in the number of macrophages expressing interleukin-1ß (IL-1ß) and abundant expression of cyclooxygenase-2 (COX-2), the inducible isoform of the key enzyme in the biosynthesis of prostaglandins (PGs), in Leydig cells. In the present study we report [1] a positive correlation between IL-1ß levels and COX-2 expression in testes of infertile patients, [2] the induction of COX-2 by IL-1ß in mouse Leydig cells (TM3) and human macrophages (THP-1), and therefore [3] evidence for an IL-1ß-dependent induction of testicular inflammatory states.