RESUMO
BACKGROUND: Cimetidine, histamine H2 receptors antagonist, has caused adverse effects on the male hormones and reproductive tract due to its antiandrogenic effect. In the testes, peritubular myoid cells and muscle vascular cells death has been associated to seminiferous tubules and testicular microvascularization damages, respectively. Either androgen or histamine H2 receptors have been detected in the mucosa and smooth muscular layer of vas deferens. Thus, the effect of cimetidine on this androgen and histamine-dependent muscular duct was morphologically evaluated. METHODS: The animals from cimetidine group (CMTG; n=5) received intraperitoneal injections of 100 mg/kg b.w. of cimetidine for 50 days; the control group (CG) received saline solution. The distal portions of vas deferens were fixed in formaldehyde and embedded in paraffin. Masson´s trichrome-stained sections were subjected to morphological and the following morphometrical analyzes: epithelial perimeter and area of the smooth muscular layer. TUNEL (Terminal deoxynucleotidyl-transferase mediated dUTP Nick End Labeling) method, NF-kB (nuclear factor kappa B) and AR (androgen receptors) immunohistochemical detection were also carried out. The birefringent collagen of the muscular layer was quantified in picrosirius red-stained sections under polarized light. The muscular layer was also evaluated under Transmission Electron Microscopy (TEM). RESULTS: In CMTG, the mucosa of vas deferens was intensely folded; the epithelial cells showed numerous pyknotic nuclei and the epithelial perimeter and the area of the muscular layer decreased significantly. Numerous TUNEL-labeled nuclei were found either in the epithelial cells, mainly basal cells, or in the smooth muscle cells which also showed typical features of apoptosis under TEM. While an enhanced NF-kB immunoexpression was found in the cytoplasm of muscle cells, a weak AR immunolabeling was detected in these cells. In CMTG, no significant difference was observed in the birefringent collagen content of the muscular layer in comparison to CG. CONCLUSIONS: Cimetidine induces significant damages in the epithelium; a possible antiandrogenic effect on the basal cells turnover should be considered. The cimetidine-induced muscle cells apoptosis confirms the susceptibility of these cells to this drug. The parallelism between enhanced cytoplasmic NF-kB immunolabeling in the damaged muscular tissue and muscle cell apoptosis suggests that this drug may avoid the translocation of NF-kB to the nucleus and interfere in the control of NF-kB-mediated smooth muscle cell apoptosis. The decreased immunoexpression of ARs verified in the damaged muscular tissue reinforces this possibility.
Assuntos
Apoptose/efeitos dos fármacos , Cimetidina/farmacologia , Músculo Liso/efeitos dos fármacos , NF-kappa B/metabolismo , Receptores Androgênicos/metabolismo , Ducto Deferente/efeitos dos fármacos , Animais , Colágeno/metabolismo , Citoplasma/efeitos dos fármacos , Citoplasma/metabolismo , Epitélio/efeitos dos fármacos , Epitélio/metabolismo , Epitélio/patologia , Antagonistas dos Receptores H2 da Histamina/farmacologia , Imuno-Histoquímica , Marcação In Situ das Extremidades Cortadas , Masculino , Microscopia Eletrônica de Transmissão , Músculo Liso/metabolismo , Músculo Liso/ultraestrutura , Ratos , Ducto Deferente/metabolismo , Ducto Deferente/patologiaRESUMO
Cimetidine, an H2 receptor antagonist used for treatment of gastric ulcers, exerts antiandrogenic and antiangiogenic effects. In the testes cimetidine impairs spermatogenesis, Sertoli cells and peritubular tissue, inducing apoptosis in the myoid cells. Regarding the importance of histamine and androgens for vascular maintenance, the effect of cimetidine on the structural integrity of the testicular vasculature was evaluated. Adult male rats received cimetidine (CMTG) and saline (CG) for 50 days. The testes were fixed in buffered 4% formaldehyde and embedded in historesin and paraffin. In the PAS-stained sections, the microvascular density (MVD) and the vascular luminal area (VLA) were obtained. TUNEL method was performed for detection of cell death. Testicular fragments embedded in Araldite were analyzed under transmission electron microscopy. A significant decrease in the MVD and VLA and a high number of collapsed blood vessel profiles were observed in CMTG. Endothelial cells and vascular muscle cells were TUNEL-positive and showed ultrastructural features of apoptosis. These results indicate that cimetidine induces apoptosis in vascular cells, leading to testicular vascular atrophy. A possible antagonist effect of cimetidine on the H2 receptors and/or androgen receptors in the vascular cells may be responsible for the impairment of the testicular microvasculature.
Assuntos
Cimetidina/toxicidade , Testículo/irrigação sanguínea , Testículo/efeitos dos fármacos , Animais , Antiulcerosos/toxicidade , Apoptose/efeitos dos fármacos , Atrofia , Antagonistas dos Receptores H2 da Histamina/toxicidade , Masculino , Microscopia Eletrônica de Transmissão , Microvasos/efeitos dos fármacos , Microvasos/patologia , Ratos , Ratos Sprague-Dawley , Testículo/patologiaRESUMO
Treatment with tacrolimus (FK-506) has been shown to induce a significant decrease in the number of spermatocytes, spermatids, and Sertoli cells. Regarding the importance of the peritubular tissue for the maintenance of Sertoli cells, the integrity of the cellular and extracellular components of the peritubular tissue was evaluated in adult rats that were treated with 1 mg/kg/day of FK-506 for 30 and 60 days. Testicular sections were used for a quantitative analysis of the peritubular cells (PCs) and were submitted to the PAS method. Paraffin sections were submitted to the TUNEL method and to immunohistochemistry for the detection of caspase-3. Several testicular fragments were analyzed under a transmission electron microscope (TEM). A weak PAS reaction was noted in the peritubular tissue of the tacrolimus-treated animals. Next to the damaged peritubular tissue, the Sertoli cell nuclei were absent or dislocated from the basement membrane. In the treated animals, the number of PCs decreased significantly compared to the control animals, and these cells showed apoptotic features, were TUNEL positive, and were caspase-3 immunolabeled. Using the TEM, apoptosis was confirmed in myoid cells; moreover, the thickness and undulation of the basal laminae and an enlargement of the collagen I layer adjacent to the myoid cells was observed. Long-term treatment with the immunosuppressor induced peritubular myoid cell death by apoptosis and disarrangement of the peritubular extracellular layers. Future studies are necessary to confirm whether the structural alterations in the seminiferous epithelium are related to the effect of FK-506 on peritubular tissue.
Assuntos
Imunossupressores/efeitos adversos , Células de Sertoli/efeitos dos fármacos , Tacrolimo/efeitos adversos , Testículo/efeitos dos fármacos , Testículo/patologia , Animais , Marcação In Situ das Extremidades Cortadas , Masculino , Ratos , Túbulos Seminíferos/efeitos dos fármacos , Túbulos Seminíferos/patologia , Células de Sertoli/patologiaRESUMO
Treatment of gastric ulcer with cimetidine reduces acid secretion and interferes in the vitamin B(12) absorption. Regarding the harmful effect of cimetidine on the seminiferous tubules, the aim of the present study was to verify if prolonged treatment with cimetidine causes vitamin B(12) deficiency and whether the testicular damages are attenuated by vitamin B(12) supplementation. Adult male rats received, for 50 days, cimetidine (CMTG), cimetidine and vitamin B(12) (CMT/B(12)G), vitamin B(12) (B(12)G) and saline solution (CG). Vitamin B(12) and homocysteine plasma levels were evaluated and the testes were embedded in glycol methacrylate for the morphometric analyses of total, epithelial and luminal areas of the seminiferous tubules, number of Sertoli cells and frequencies of tubules according to stages and containing Sertoli and germ cells in the lumen. Terminal deoxynucleotidyl-transferase mediated dUTP nick end labeling (TUNEL) method and proliferating cell nuclear antigen (PCNA) immunohistochemistry were carried out. CMTG showed TUNEL-positive Sertoli cells and significant reductions in the epithelial and total tubular areas, number of Sertoli cells and frequency of tubules VII-VIII. In the CMT/B(12)G, the number of Sertoli cells and the epithelial and total tubular areas were similar to CG. The number of Sertoli cells (in B(12)G) and the frequency of tubules at stages VII-VIII (in B(12)G and CMT/B(12)G) increased significantly; PCNA-positive Sertoli cells were found in these groups. Although cimetidine was not able to induce vitamin B(12) deficiency, this drug causes tubular atrophy due to Sertoli cell damage and loss of germ cells. However, vitamin B(12) supplement is able to stimulate spermatogenesis and restore the number of Sertoli cells, softening the harmful effect of cimetidine on spermatogenesis.
Assuntos
Cimetidina/farmacologia , Antagonistas dos Receptores H2 da Histamina/farmacologia , Epitélio Seminífero/efeitos dos fármacos , Vitamina B 12/farmacologia , Animais , Imuno-Histoquímica , Marcação In Situ das Extremidades Cortadas , Masculino , Ratos , Epitélio Seminífero/metabolismoRESUMO
BACKGROUND: Tacrolimus (FK-506) is an immunosuppressant that binds to a specific immunophilin, resulting in the suppression of the cellular immune response during transplant rejection. Except for some alterations in the spermatozoa, testicular morphological alterations have not been described in rats treated with tacrolimus. In the present study, we purpose to evaluate if the treatment with tacrolimus at long term of follow-up interferes in the integrity of the seminiferous tubules. METHODS: Rats aging 42-day-old received daily subcutaneous injections of 1 mg/kg/day of tacrolimus during 30 (T-30) and 60 (T-60) days; the rats from control groups (C-30 and C-60) received saline solution. The left testes were fixed in 4% formaldehyde and embedded in glycol methacrylate for morphological and morphometric analyses while right testes were fixed in Bouin's liquid and embedded in paraffin for detection of cell death by the TUNEL method. The epithelial and total tubular areas as well as the stages of the seminiferous epithelium and the number of spermatocytes, spermatids and Sertoli cells (SC) per tubule were obtained. RESULTS: In the treated groups, seminiferous tubules irregularly outlined showed disarranged cellular layers and loss of germ cells probably due to cell death, which was revealed by TUNEL method. In addition to germ cells, structural alterations in the SC and folding of the peritubular tissue were usually observed. The morphometric results revealed significant decrease in the number of SC, spermatocytes, spermatids and significant reduction in the epithelial and total tubular areas. CONCLUSION: Tacrolimus induces significant histopathological disorders in the seminiferous tubules, resulting in spermatogenic damage and reduction in the number of Sertoli cells. A careful evaluation of the peritubular components will be necessary to clarify if these alterations are related to the effect of FK-506 on the peritubular tissue.