Received: December 30, 2010; Received in revised form: February 17, 2011; Accepted: March 22, 2011; Published Online: April 18, 2011 Melatonin protects human spermatozoa from apoptosis via melatonin receptor– and extracellular signal–regulated kinase-mediated pathways Javier Espino, M.Sc., Águeda Ortiz, B.Sc., Ignacio Bejarano, M.Sc., Graciela M. Lozano, Ph.D., Fabian Monllor, B.Sc., Juan F. García, M.D., Ana B. Rodríguez, Ph.D., José A. Pariente, Ph.D. Objective To evaluate whether the protective effect of melatonin on H2O2-induced caspase activation and DNA fragmentation depends on the interaction between melatonin and its surface receptors. Design Laboratory study. Setting Center for assisted human reproduction at a Spanish hospital. Patient(s) Twenty-one healthy donors. Intervention(s) Human spermatozoa were treated with increasing concentrations of hydrogen peroxide (H2O2; 1μM, 10 μM, 100 μM, 1mM) and preincubated with 1 mM melatonin. Main Outcomes Measure(s) Activation of caspase-3 and -9 as well as DNA fragmentation were examined by fluorescence methods. Result(s) Our findings showed that H2O2 induced a significant increase in caspase-9 and caspase-3, which was dose independent. Conversely, pretreatment with melatonin reduced H2O2-mediated caspase activation in a dose-dependent way. Moreover, the antiapoptotic effects of melatonin in ejaculated human spermatozoa may involve membrane melatonin receptor MT1. In addition, we found that the survival-promoting pathway extracellular signal–regulated kinase (ERK) is likely to have a role in the protective actions of melatonin in ejaculated human spermatozoa. Finally, we confirmed these results further by demonstrating that melatonin prevention of H2O2-induced DNA fragmentation is dependent on both MT1 receptor and ERK signaling. Conclusion(s) These results indicate that the stimulation with melatonin triggers a set of events culminating in cell death prevention in ejaculated human spermatozoa.
Melatonin Prevents Sperm Suicide
Received: December 30, 2010; Received in revised form: February 17, 2011; Accepted: March 22, 2011; Published Online: April 18, 2011 Melatonin protects human spermatozoa from apoptosis via melatonin receptor– and extracellular signal–regulated kinase-mediated pathways Javier Espino, M.Sc., Águeda Ortiz, B.Sc., Ignacio Bejarano, M.Sc., Graciela M. Lozano, Ph.D., Fabian Monllor, B.Sc., Juan F. García, M.D., Ana B. Rodríguez, Ph.D., José A. Pariente, Ph.D. Objective To evaluate whether the protective effect of melatonin on H2O2-induced caspase activation and DNA fragmentation depends on the interaction between melatonin and its surface receptors. Design Laboratory study. Setting Center for assisted human reproduction at a Spanish hospital. Patient(s) Twenty-one healthy donors. Intervention(s) Human spermatozoa were treated with increasing concentrations of hydrogen peroxide (H2O2; 1μM, 10 μM, 100 μM, 1mM) and preincubated with 1 mM melatonin. Main Outcomes Measure(s) Activation of caspase-3 and -9 as well as DNA fragmentation were examined by fluorescence methods. Result(s) Our findings showed that H2O2 induced a significant increase in caspase-9 and caspase-3, which was dose independent. Conversely, pretreatment with melatonin reduced H2O2-mediated caspase activation in a dose-dependent way. Moreover, the antiapoptotic effects of melatonin in ejaculated human spermatozoa may involve membrane melatonin receptor MT1. In addition, we found that the survival-promoting pathway extracellular signal–regulated kinase (ERK) is likely to have a role in the protective actions of melatonin in ejaculated human spermatozoa. Finally, we confirmed these results further by demonstrating that melatonin prevention of H2O2-induced DNA fragmentation is dependent on both MT1 receptor and ERK signaling. Conclusion(s) These results indicate that the stimulation with melatonin triggers a set of events culminating in cell death prevention in ejaculated human spermatozoa.