Study of Sertoli cells and spermatogenic cells in rats with experimentally induced metabolic syndrome and after balneophysiotherapy

Introduction. Metabolic syndrome (MS) can cause impaired spermatogenesis and a decrease in sperm counts. However, the details of the effect of MS on developing spermatogenic cells remain unclear. Difficulties in solving this problem, the inconsistency of published clinical data, indicate the advisability of using experimental models to solve this urgent problem of andrology and reproductology.The study objective is to describe to investigate the specifics of the course of meiotic prophase I and the activity of the processes of phagocytosis and autophagy in Sertoli cells of rats with experimentally induced MS and in the course of therapeutic and prophylactic procedures during the development of experimental MS.Materials and methods. The animals were divided into three groups, each of which included four sexually mature male rats: 1st group – males fed a standard diet; 2nd group – males receiving a diet high in fat and fructose for 60 days; 3rd group – males with MS receiving sulphate mineral waters therapy, low-intensity ultrahigh frequency electromagnetic radiation therapy. Testicular cells were examined using light and transmission electron microscopy. For the first time in animals with MS, an immunocytochemical study of the peculiarities of chromosome synapsis in prophase I of meiosis was carried out on the basis of analysis of spread synaptonemal complexes of meiotic chromosomes and immunocytochemical analysis of Sertoli cells and spermatogenic cells in squashed preparations of seminiferous tubules. The parametric Student’s t-test and the nonparametric Mann–Whitney U-test were used for statistical data processing.Results. As a result of a histological study of the structure of the seminiferous tubules of animals of three groups, a statistically significant decrease in the indices of the spermatogenesis index in 2nd and 3rd groups compared to the control was revealed. Immunomorphologically, in the spread nuclei of primary spermatocytes of rats of the 2nd and 3rd groups, violations of the architectonics of nuclei, the formation of synaptonemal complexes fragments and circular synaptonemal complexes, numerous atypical inclusions were found. Signs of pachytene arrest were found in 40–50 % of spermatocyte nuclei. In the study of squashed cells preparations of the seminiferous tubules of rats of the 2nd and 3rd groups, signs of phagocytosed synaptonemal complexes were found in the cytoplasm of Sertoli cells, which were confirmed using antibodies to the SCP3 protein. Thus, evidence for the phagocytosis of degenerating primary spermatocytes by Sertoli cells has been obtained. In Sertoli cells, spermatocytes and spermatids, many autophagosomes are found, using LC3B protein marker. The presence of autophagosomes in Sertoli cells and spermatogenic cells in animals of these two groups was also confirmed by electron microscopy. In male rats of the 2nd group, significant disturbances in the structure of the pachytene nuclei were revealed. In the cytoplasm of Sertoli cells and spermatids of rats of the 2nd group, lipid droplets, numerous phagolysosomes containing cell detritus were revealed. Structural damage and phagocytosis of mitochondria were found in Sertoli cells and spermatocytes. Аutophagy in Sertoli cells were most distinctive in animals of the 3rd group.Conclusion. In male rats with experimental MS, significant disturbances in the structure of the nuclei of meiotic cells, a high content of primary spermatocytes with signs of pachytene arrest were revealed. The results obtained are in good agreement with the data of other authors, who revealed a decrease in the number of spermatozoa in the epididymis of rats and mice when modeling MS. It is assumed that the activation of autophagy is an important factor in supporting the viability of Sertoli cells and supporting the viability of germ cells in stressful situations, including MS. Apparently, autophagy is an adaptive mechanism that removes the remnants of apoptotic spermatogenic cells that are selected as a result of MS development.

Exposure to the anthelmintic dinitroaniline oryzalin causes changes in meiotic prophase morphology and loss of synaptonemal complexes in the nematode Caenorhabditis elegans

The anthelmintic dinitroaniline oryzalin interferes with the formation of microtubules and inhibits meiosis and mitosis in nematodes. Exposure to oryzalin resulted in deterioration in morphology of the oocytes and loss of synaptonemal complexes at meiotic prophase I. The nuclear matrix and envelope were poorly formed, and the central rachis was diminished. These results provide the basis for the loss of fecundity after treatment with the oryzalin resulting in control of parasitic nematodes.

Loss of the central rachis and synaptonemal complexes during meiotic prophase in female Ascaris lumbricoides var. suum after exposure to albendazole

Albendazole, a benzimidazole anthelmintic, interferes with the formation of microtubules and inhibits meiosis in the nematode Ascaris lumbricoides var. suum. Pigs treated with albendazole had worms in their uteri that had a severely deteriorated central rachis, complete loss of synaptonemal complexes and irregular oocytes at meiotic prophase I. The nuclear matrix and envelope were poorly formed and there was formation of accessory nuclei. This study represents the first examination of the changes in meiotic nuclear architecture and meiotic chromosomes after exposure to albendazole. These results provide the basis for the loss of fecundity in A. suum after exposure to albendazole resulting in control in the population of the parasitic nematode.

Heterochiasmy and Sexual Dimorphism: The Case of the Barn Swallow (Hirundo rustica, Hirundinidae, Aves)

Heterochiasmy, a sex-based difference in recombination rate, has been detected in many species of animals and plants. Several hypotheses about evolutionary causes of heterochiasmy were proposed. However, there is a shortage of empirical data. In this paper, we compared recombination related traits in females and males of the barn swallow Hirundo rustica (Linnaeus, 1758), the species under strong sexual selection, with those in the pale martin Riparia diluta (Sharpe and Wyatt, 1893), a related and ecologically similar species with the same karyotype (2N = 78), but without obvious sexual dimorphism. Recombination traits were examined in pachytene chromosome spreads prepared from spermatocytes and oocytes. Synaptonemal complexes and mature recombination nodules were visualized with antibodies to SYCP3 and MLH1 proteins, correspondingly. Recombination rate was significantly higher (p = 0.0001) in barn swallow females (55.6 ± 6.3 recombination nodules per autosomal genome), caused by the higher number of nodules at the macrochromosomes, than in males (49.0 ± 4.5). They also showed more even distribution of recombination nodules along the macrochromosomes. At the same time, in the pale martin, sexual differences in recombination rate and distributions were rather small. We speculate that an elevated recombination rate in the female barn swallows might have evolved as a compensatory reaction to runaway sexual selection in males.

Cytological evidence for automictic thelytoky in parthenogenetic oribatid mites (Acari, Oribatida): Synaptonemal complexes confirm meiosis in Archegozetes longisetosus

Diplo-diploid parthenogenesis (thelytoky) is a widespread phenomenon in the mite taxon Sarcoptiformes, and is unusually frequent in the suborder Oribatida, where it characterizes almost 10% of extant species, including whole genera and families. Based on molecular and cytological data, terminal fusion automixis with an inverted meiotic sequence based on holokinetic chromosomes has been suggested as the reproductive mode in these mites. However, unequivocal structural evidence for meiosis is missing. The model organism Archegozetes longisetosus, a thelytokous member of the parthenogenetic family Trhypochthoniidae, was studied to gain ultrastructural insight in oocyte progression and meiotic processes. In this study, ovarian nuclear organization of its tritonymphal instar was examined by transmission electron microscopy (TEM). Numerous synaptonemal complexes were observed in the ovary, unequivocally confirming automixis (meiotic thelytoky) in oribatid mites for the first time. No recombination nodules were found. The nuclei are transcriptionally active in late prophase. Inverted meiosis is discussed as a result of the spatial arrangement of chromatid segregation.

Genotoxic effects of N-nitrosodimethylamine in somatic and generative cells of mice

N-Nitrosodimethylamine (NDMA) was shown to have genotoxic properties in acute and subacute studies on laboratory mice. The organ-specificity of the genotoxic effect of NDMA was revealed using the Comet assay. The most sensitive organs to the action of NDMA were kidneys and liver. DNA damage in liver cells of NDMA-treated animals at doses of 4.0 and 8.0 mg/kg, increased compared to control in 6.9 and 12.5 (р < 0.001), and in kidney cells – in 8.1 and 14.2 times (р < 0.001), respectively. NDMA also showed genotoxic activity in the reproductive cells of experimental animals, causing structural disorders of synaptonemal complexes in spermatocyte. In NDMA-treated animals at a dose of 2.0 mg/kg in acute and subacute studies, the level of spermatocytes with damaged synaptonemal complexes increased statistically significantly compared to control in 6.0 and 7.0 (р < 0.05) times, respectively.