DETECTION OF HUMAN MEIOTIC AND SPERMATOGENETIC ANOMALIES USING LIGHT, ELECTRON AND FLUORESCENCE MICROSCOPY

Abstract

Introduction. Infertility is diagnosed in 10–15 % of couples wishing to have children. In about half cases, the cause is a disorders of male fertility. Defects of spermatogenesis are often caused by the damages of key events of prophase I meiosis – synapsis, repair, recombination and desynapsis of homologous chromosomes. All these events are connected with the unique structure of the meiotic nucleus – the synaptonemal complex. Behavior of the lateral elements of the synaptonemal complex serve as a paradigm of chromosome behavior in the meiosis prophase and an indicator of disorders of the chromosome synapsis.Objective is the evaluation of the possibilities analysis of the spread spermatocyte nuclei for establishing the causes and mechanisms of spermatogenesis disturbance and identification of the genetic and reproductive risks of using testicular spermatozoa for in vitro fertilization programs using intracytoplasmic sperm injection.Materials and methods. The material of the study were the biopsies of testes obtained from infertile patients by method of open multifocal testicular biopsy.The suspensions of testicular cells were examined by light microscopy. The structure of the synaptonemal complexes in spread nuclei of primary spermatocytes was studied by electron microscopy. The target meiotic proteins in such nuclei (SCP3, RAD51, MLH1, γH2AX) were localized by the fluorescence microscopy.Results. There were described possibilities of light microscopic analysis of the testicular cells suspensions for the evaluation of spermatogenesis. The features of the structural organization of the sex (XY) bivalent were presented which underlie the determination of the stages of meiotic prophase in human spermatocytes. The signs of the meiotic arrest, the disturbance of the architectonics of meiotic nuclei, synapsis, recombination and chromatin silencing in human spermatocytes at the meiotic prophase I are described in details.Сonclusion. The presented results demonstrate the expediency of introducing methods of electron microscopy and immunocytochemical analysis of the spread spermatocytes nuclei in the practice of the reproductive centers. The using of these methods makes it possible for understanding the mechanisms of infertility genesis, revealing genetic and reproductive risks of using testicular spermatozoa in the fertilization program.

Keywords

• spermatogenesis
• meiosis
• spermatocytes
• synaptonemal complex
• meiotic arrest
• infertility