Chromosomal abnormalities and the morphology of mouse sperm heads (original) (raw)
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Influence of partial deletion of the Y chromosome on mouse sperm phenotype
Reproduction, 1991
Two congenic strains of mice (control, B10.BR/SgSn; mutant, B10.BR\x=req-\ Ydel/Ms with partial deletion of the Y chromosome) were examined. In control males, 22\m=.\6%of spermatozoa had abnormal heads; in mutant males, there were 64\m=.\2%, the most common being heads with flat acrosomes. Sodium dodecyl sulphate polyacrylamide gel electrophoresis of mature sperm proteins, followed by acrosin assay and acrosome silver staining, revealed a reduced concentration of acrosin in acrosomal caps in 35\m=.\8%of the spermatozoa in mutant males. Electron microscope analysis showed that some of the round, early spermatids in the mutants had normally formed acrosomal caps but lacked the proacrosomal granule and had no, or only scarce, acrosomal material. These observations indicate that formation of the acrosomal cap is controlled separately from the synthesis of the acrosomal material and suggest that some factors linked on the Y chromosome are involved in the control of acrosome development.
Ultrastructure sperm defects in male mice during carcinogenicity of urethane and indoxan
acgssr.org
The effect of two carcinogenic and tumour induction chemicals (urethane and indoxan) on mice spermatozoal morphology has been investigated. Administration of these carcinogens resulted in a significant (P<0.001) increase in abnormal sperm morphology during treatment period and especially during tumor initiation. Transmission electron microscopy of mice sperm treated with urethane and indoxan revealed ultrastructural damage particularly on the axoneme of the sperm tail at the level of middle piece. The malformed ultrastructure was illustrated as extensive mitochondrial vacuolation and loss of cristae. Furthermore, axonemal deficiencies were revealed as complete disappearance of one or more of the outer dense fibers and one or more of the nine fiber doublets. Additionally, lesion of the cytoplasmic membrane and fibrous sheath of the sperm tail has been observed. Results suggest that acute exposure to carcinogens in male mice (as well as carcinogenesis process) resulted in not only abnormal sperm morphology but also malformed sperm ultrastructure. Collectively, these results highlight the deterioration of spermatogenesis exerted by carcinogenicity of both urethane and indoxan.
Cytogenetic analysis of human spermatozoa using intracytoplasmic sperm injection into mouse oocytes
Russian Journal of Genetics, 2005
The chromosome complement of human spermatozoa has been analyzed after their intracytoplasmic injection into unfertilized mouse oocytes. A total of 427 metaphase plates have been obtained, including 176 metaphase plates from spermatozoa with normal head morphology (108 and 68 spermatozoa from patients with normal (the control group) and abnormal spermogram parameters, respectively), and 251 metaphase plates from spermatozoa with abnormal heads (76, 91, 67, and 17 spermatozoa with large, amorphous, elongated, and round heads, respectively). The frequency of chromosome abnormalities in the control group is 26.1%, with hyperploidy, hypoploidy, and structural aberrations accounting for 7.4, 12.3, and 6.4% of the abnormalities, respectively. In none of the groups did the ratio between the numbers of X-and Y-bearing spermatozoa significantly differ from 1 : 1. The diploidy frequency was significantly higher in spermatozoa with large and amorphous heads compared to the control group (2.36, 3.29, and 0%, respectively). None of the groups of spermatozoa differed from the control group with respect to the frequency of structural aberrations. The type of the abnormal head morphology has been found to be correlated with the sperm chromosome complement.
Methods in Molecular Biology, 2008
The father, like the mother, can transmit genetic defects that are detrimental for development and genetic health for his children, but the mechanisms for paternallymediated abnormal reproductive outcomes remain poorly understood. A battery of sensitive methods has been developed for detecting genetic damage associated with infertility, spontaneous abortions, as well as inherited defects in children such as aneuploidy syndromes, translocation carriers, and certain genetic diseases directly in sperm. Among these, fluorescence in situ hybridization (FISH) sperm-based assays for measuring numerical abnormalities and structural chromosomal aberrations are now available for an expanding number of species including humans, rodents, and several domesticated animals. This new generation of sperm FISH methods have identified several paternal risk factors such as age, various drugs, lifestyles, and various environmental and occupational exposures. These sperm FISH assays provide new opportunities to identify and characterize male reproductive risks associated with genetic, lifestyle and environmental factors. This chapter outlines the laboratory methods for the detection of sperm with chromosomal structural aberrations in humans (ACM assay) and mice (CT8 assay) that have been validated for detecting environmental germ cell mutagens.
Mutation frequency declines during spermatogenesis in young mice but increases in old mice
Proceedings of the National Academy of Sciences, 1998
Five percent of live-born human offspring will have a genetic disorder. Of these, 20% are because of germ-line de novo mutations. Several genetic diseases, such as neurofibromatosis and Duchenne muscular dystrophy, are associated with a high percentage of de novo germ-line mutations. Until recently, a direct analysis of spontaneous mutation frequencies in mammalian germ cells has been prevented by technical limitations. We have measured spontaneous mutation frequencies in a lacI transgene by using enriched populations of specific spermatogenic cell types. Similar to previously published results, we observed a lower mutation frequency for seminiferous tubule cell preparations, which contain all stages of spermatogenesis, relative to somatic tissues. We made the unexpected observation of a decline in mutation frequency during spermatogenesis, such that the mutation frequencies of type B spermatogonia and all subsequent stages of spermatogenesis are lower than the frequency for primitive type A spermatogonia. In addition, spermatogenic cells from old mice have significantly increased mutation frequencies compared with spermatogenic cells from young or middle-aged mice. Finally, the mutation frequency was observed to increase during spermiogenesis in postreplicative cell types when spermatogenic cells were obtained from old mice.
Spermatogenic defects in F2 mice between normal mouse strains C3H and C57BL/6 without mutation
Congenital anomalies, 2012
Genetic disorders are usually considered to be caused by harmful gene mutations, as well as by chromosomal aberrations, including small insertions, duplications and/or deletions. However, as infertile individuals often arise among the offspring of crosses between two fertile mouse strains, we postulate that a certain combination of 'normal' genes with neither gene mutations nor chromosomal aberrations can cause such serious phenotypic alterations as reproductive dysfunction. In this study, we show evidence that a combination of multiple normal genes from two different normal mouse strains manifests a wide range of male reproductive dysfunctions, from benign changes to complete infertility. These abnormal phenotypes are thought to have occurred by epistatic interactions of alleles.
Environmental science and pollution research international, 2018
DNA fragmentation can be deleterious on spermatozoon morphology but the pathogenesis of teratozoospermia associated with DNA breaks is not fully understood, even if oxidative attacks and defects in chromatin maturation are hypothesized. Therefore, this study is one of the first to clarify on the underlying hypothesizes behind such observations. The objectives of our study were to assess the role of oxidative attacks in DNA damage pathogenesis in ejaculated spermatozoa from patients with isolated teratozoospermia. We aimed to assess the correlation of DNA breaks with morphologically abnormal spermatozoa, as well as ROS level and impairment chromatin condensation. A total of 90 patients were divided into two groups, men with isolated teratozoospermia (n = 60) and men with normal semen parameters (n = 30) as controls. DNA fragmentation was evaluated by TUNEL assay; chromatin immaturity was studied using acridine orange and toluidine blue staining. We evaluated the ability of spermatozo...