Human round spermatids from azoospermic men exhibit oocyte-activation and Ca2+ oscillation-inducing activities.
During mammalian fertilization, intracellular Ca2+ oscillations are important for both oocyte activation and embryonic development. As the ability of round spermatids (ROS) to induce Ca2+ oscillations and oocyte activation is different between species, we examined Ca2+ oscillation- and oocyte activation-inducing abilities of human ROS originating from patients with non-obstructive azoospermia. Human ROS from 11 non-obstructive azoospermic patients were collected during their TESE-ICSI cycles. Following injection into mature unfertilized mouse oocytes, we examined the oocyte-activating and Ca2+ oscillation-inducing activities of ROS by using Ca2+ imaging and confocal laser scanning microscopy (mouse test). In these 11 cases, clinical TESE-ICSI using mature testicular spermatozoa was successful, with the exception of one case in which only one sperm-injected oocyte was not fertilized. The mean fertilization rate was 70.1% (40-100%); the mean cleavage rate was 97.9% (46/47). Two pregnancies were established from 10 transfer cycles (PR; 20%). When the ROS from these patients were injected into mouse oocytes, the ROS from all patients induced at least some intracellular Ca2+ oscillations (25-100%). In all patients, 40 out of 82 oocytes injected with ROS exhibited normal oscillation patterns of [Ca2+]i. Human spermatogenetic cells acquired oocyte-activating and Ca2+ oscillation-inducing abilities at the round spermatid stage, an earlier stage than found for rodent cells. These data indicate that human ROS might be useful for clinical treatments of non-obstructive azoospermic patients exhibiting mature spermatozoa in biopsied specimens.
Yazawa
H
H
Department of Obstetrics and Gynecology, Fukushima Red Cross Hospital, Fukushima 960-8530, Japan. ikyoku12@fukushima-med-jrc.jp
Yanagida
K
K
Sato
A
A
D000818:Animals; D053713:Azoospermia / Q000503:physiopathology*; D020013:Calcium Signaling / Q000502:physiology*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D009865:Oocytes / Q000502:physiology*; D013045:Species Specificity; D020554:Sperm Injections, Intracytoplasmic; D013084:Sperm-Ovum Interactions / Q000502:physiology; D013087:Spermatids / Q000502:physiology*