Melatonin counteracts cadmium-induced rat testicular toxicity via the mechanistic target rapamycin (mTOR) pathway.

The protective action of melatonin (MLT) against the harmful effects of cadmium (Cd) on testicular activity in rats has been documented previously; however, the involved molecular mechanisms have yet to be elucidated. Herein, we investigate the involvement of the mammalian target of rapamycin (mTOR) on the ability of MLT to counteract the damage induced by Cd on the rat testicular activity. Our study confirmed that Cd has harmful effects on the testes of rats and the protective action exerted by MLT. We reported, for the first time, that the addition of rapamycin (Rapa), a specific mTOR inhibitor, to animals co-treated with Cd and MLT completely abolished the beneficial effects exerted by MLT, indicating that the mTOR pathway partially modulates its helpful effects on Cd testicular toxicity. Interestingly, Rapa-alone treatment, provoking mTOR inhibition, produced altered morphological parameters, increased autophagy of germ and somatic cells, and reduced serum testosterone concentration. In addition, mTOR inhibition also reduced protein levels of markers of steroidogenesis (3ß-Hydroxysteroid dehydrogenase) and blood-testis barrier integrity (occludin and connexin 43). Finally, Rapa altered sperm parameters as well as the ability of mature spermatozoa to perform a proper acrosome reaction. Although further investigation is needed to better clarify the molecular pathway involved in MLT action, we confirm that MLT alleviating Cd effects can be used as a supplement to enhance testicular function and improve male gamete quality.

First evidence of a cDNA encoding for a melatonin receptor (mel 1b) in brain, retina, and testis of Pelophylax esculentus.

Melatonin, nocturnally secreted by the pineal gland, regulates a variety of physiological functions, including reproduction. Here, we investigated the evidence of melatonin binding sites in frog tissue (brain, retina, and testis) through saturation and competition binding experiments. In the frog, Pelophylax esculentus, our results confirm the presence of a single class of melatonin-specific binding sites in the brain and retina, but not in the testis. Further experiments have been done using biomolecular approaches (PCR analysis). Here, we report the isolation of a cDNA encoding for a melatonin receptor type (mel 1b) from brain, retina, and testis of the P. esculentus. PCR analysis revealed that melatonin expression is higher in the brain and retina, whereas it is lower in the testis. The presence of a melatonin receptor transcript in the frog testis corroborates our previous results obtained in in vitro experiments that suggest that melatonin might act directly in male vertebrate gonads, and indicates that the frog testis may be a suitable model to verify the role of indolamine in testicular activity.

Bilateral varicocele: single transscrotal approach for Tauber antegrade sclerotherapy.

OBJECTIVE: To describe the results of a new simple technique of single transscrotal approach for Tauber antegrade sclerotherapy in bilateral varicocele. MATERIALS AND METHODS: During the period March 1998-June 2001, overall 341 patients were treated for varicocele using Tauber antegrade sclerotherapy. In 39 of these patients, sclerotherapy was performed bilaterally in the same session whilst in 34, rather than making two incisions at the root of the two hemiscrotums, a single incision was made on the median raphe. During this period, the same approach was used in 4 patients with left varicocele and right hydrocele, 2 patients with left varicocele and right epididymis cyst, 1 patient with bilateral varicocele and bilateral hydrocele, 1 patient with bilateral hydrocele and left varicocele. RESULTS: Maximum ray exposure time was 58 seconds (mean 30). Oro-tracheal intubation was not necessary in any of the patients. In 12 patients, besides local anesthesia, additional sedation was given. Slight bleeding of the wound, occurring in 3 patients, was medicated in the outpatient department. CONCLUSIONS: Patients prefer a single incision. When the incision is made on the median raphe, no scars remain. In bilateral varicocele, the single approach reduces invasiveness and increases patient satisfaction.