Meiosis In Human Males With Azoospermia

Spermatogenesis is a complex and regulated progres(s in mammals. During meiosis I, meiotic recombination play a crucial role in holding homologous chromosomes together and guarantee their accurate segregation into daughter cells. Present study was designed in order to investigate the roles of abnormal meiotic pairing, synapsis and recombination during spermatogenesis leading to male infertility in humans.1. Reciprocal translocation is one of the most qommon structural chromosomal rearrangements in human beings; it is widely recognized to be associated with male infertility. Spermatocyte spreading and immunostaining were applied to detect meiotic prophase I progression, homologous chromosome pairing, synapsis and recombination in three reciprocal translocation46,XY,t(8;15),46,X,t(Y;1)(p11.3;p31) and in46,XY, t(5;7;9;13)(5q11;7p11;7p15;9q12;13p12) carriers. An increase in zygotene while decrease in the pachytene spermatocytes were observed in the patients when compared with the controls indicating disturbed meiotic progression. The variant histone yH2AX and BRCA1proteins were found to be located at the asynapsed quadrivalents. A significant reduction in XY recombination frequency was observed in the patients. The number of MLH1foci on translocated as well as non-translocated chromosomes per cell were significantly decreased in the patients as compared to controls, we have reported a series of events that may have caused infertility in translocation patients.2. Men with47, XYY syndrome are presented with varying physical attributes and degrees of infertility. Spermatocyte spreading and immunostaining were applied to detect meiotic prophase I progression, homologous chromosome pairing, synapsis, and recombination in two azoospermia patient with47, XYY and48,XYY,+sSMC. The meiotic prophase I progression was disturbed in the patients as compared with the controls. The recombination frequencies on XY chromosome was significantly lower in the patient48,XYY,+sSMC than in the controls. More interestingly, besides recombination on short arms, recombination on the long arms of Y chromosomes was also observed in the patient47,XYY. gamma-H2AX staining completely disappeared from the synapsed regions of Y chromosomes in the patient47,XYY. The findings may elucidate the impairment mammalian meiosis caused by extra Y chromosome may have caused infertility in XYY patients.3. The abnormal meiotic synapsis can affect spermatogenesis, leading to male infertility.We used immunostaining technology to examine the early stages of meiosis in testicular tissues obtained from men presented for evaluation at infertility clinics, we compared meiotic progression, pairing and synapsis in patients with normal fertile controls. In some individuals, we observed complete meiotic arrest associated with abnormalities in synapsis. There was a certain proportion of desynapsis spermatocytes in some patients with azoospermia. The findings may elucidate the abnormal chromosomal synapsis is one of the main causes of human infertility.