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The response of the mouse male germ cells exposed to gold nanoparticles (approximately 2.5 nm) was studied. Our investigation demonstrates that treatment with Au nanoparticles for four days does not impair the architecture of the spermatogenic epithelium. Cytogenetic evaluation using micronucleus assay showed that gold nanoparticles can affect the chromosomes of early primary spermatocytes. However, gold nanoparticles did not induce chromosome abnormalities in spermatogonial stem cells. Further, the cauda epididymal sperm was isolated on the 14th day after treatment and was incubated in SDS solution (Na sodium dodecyl) and then in a solution containing DTT (dithiothreitol) to induce nuclear chromatin decondensation. Observations showed that after four days of treatment of spermiogenic (postmeiotic) cells with gold nanoparticles the decondensation process had no differences from the control. On the contrary, in the experiment with the same cells and period of fixation but with a single exposure to gold nanoparticles, the number of mature gametes with totally decondensed nuclei reached 100% as opposed to 44% in the controls.

Drinking sulfate mineral water in combination with low-intensive infra-red laser or magneto-laser radiation is shown to effectively depress development of different forms of pathological mitoses in spermatogones of irradiated rats and in their first-generation progeny.

The ability of dimethylnitrosourea (DMNU) to induce dominant lethal mutations in germ cells and chromosome aberrations in bone marrow cells of male CBAB6F1 mice was studied. At a mutagen dose of 200 mg/kg, mortality was 19% in the second week after treatment (being 5% in the control) and the frequency of bone marrow cells containing chromosome aberrations was 19.6% 24 h after treatment. DMNU induces dominant lethals in postmeiotic cells and in spermatogonia; the effects in spermatozoids and spermatogonia are equal. Chromosome aberrations in spermatocytes induced by DMNU are not realized as dominant lethals. The sensitivity of mouse strains to the clastogenic effect of DMNU ranged in an order similar to that observed in experiments with thioTEPA. The most sensitive was the TPS strain (29.2 +/- 4.6% of cells with chromosome aberrations), the most resistant-the CBA/Lac strain (9.5 +/- 2.9%). DMNU exhibited a relatively poor clastogenic activity; the effect in bone marrow cells was higher than that in male germ cells.

The experiments performed on Wistar rats showed morphological damages of the rat testis over a one-month period after platidiam administration (4 mg/kg, one-time intravenous injection), namely a decrease in the index of spermatogenesis, in the number of normal spermatogonia, Leydig cells, and testis tubes at the 12th stage of meiosis and an increase in the number of testis tubes squamous epithelium. In the remote period (3 and 6 month after platidiam administration) the recovery of morphological and functional state of the rat testis was observed.

The main components of chromatin (DNA and protamine-like proteins) were studied in the Dipin- and NMU-treated mouse spermatogenic cells using quantitative cytochemistry. Marked variation of DNA content and deficiency of the basic nuclear proteins have been shown in epididymal spermatozoa developed from cells, which were at the moment of treatment either at the early prophase I or at intermediate stages of spermiogenesis. These stages are, respectively, one of genetically most sensitive stages and a stage of active synthesis of spermiospecific proteins, which play an important role in condensation and stabilization of gamete chromatin. The combined use of DNAse I and Feulgen reaction allowed us to obtain new data about cytochemical properties of chromatin in the other types of mouse germ cells after treatment with chemical mutagens.

It was shown using the micronucleus test and estimating the defects of sperm heads that premeiotic and meiotic mammalian cells are genetically very sensitive to Dipin and nitrosomethylurea. In rats, unlike mice, the stem and differentiating spermatogonia with serious chromosomal defects are not eliminated and pass through a "sieve" of mitotic and meiotic divisions reaching the stage of round spermatids. Our observations suggest long-term preservation Dipin-induced, rather than nitrosomethylurea-induced, mutations in the stem cells of both mice and rats.

ThioTEPA was injected intraperitoneally into female 101/H and CBA mice on day 12 of pregnancy at a dose of 2.5 mg/kg body weight. As a result, the number of prospermatogonia in 19-day-old male fetuses decreased to 78.8% in 101/H mice and to 63.7% in CBA mice. The gametotoxic effect on the male offspring (F1) in 101/H mice treated with thioTEPH included the significant decrease in the number of spermatogonia A, spermatocytes I at preleptotene and pachytene, as well as of spermatids at the stage 7 of development. Interstrain differences are described in the intensity of spermatogenesis in the mature intact animals and in regeneration capacity of gonads after prenatal thioTEPA administration.

Inactivated bacterial vaccine, containing K. pneumoniae, S. aureus, P. vulgaris and E. coli antigenic complexes were tested for mutagenicity in the test described by Ames et al. and in vivo, in experiments on mice. In Salmonella typhimurium cells, strain TA-98 and TA-100, the preparation (5-75 mg/ml) did not increase the frequency of reversions and histidine-independence either in direct experiments or after metabolic activation with rat liver homogenate. In experiments on mice the vaccine (3.3 mg/kg and 33 mg/kg) did not induce chromosomal anomalies in spermatogonia. In all experiments the mutagens used for positive control produced a mutagenic effect.

Sensitivity of spermatogonia of 11 mouse inbred strains to induction of chromosome damages by thiophosphamide (thioTEPA) was studied. Metaphase chromosome preparations were made 24 h after treatment with thioTEPA (at 2.25 mg/kg, i/p). With respect to frequency of cells with chromosome damages, strains were ranked as follows: A/Sn (17.5 + 4.4%) greater than 101/H greater than TPS greater than WR = C57BL/6 = AKR = NZB greater than CBA/Lac greater than C3H/Sn greater than MRL greater than BALB/c (5.0 + 2.2%). This distribution does not coincide with that for sensitivity of bone marrow cells, though the data support, in general, the estimations obtained earlier for strains' mutability. Comparison of the data presented with those from literature demonstrates that the sensitivity to clastogenic effect of thioTEPA (and other alkylating agents) correlates neither with spontaneous level of SCE, nor with unscheduled DNA synthesis, nor with radiosensitivity of inbred mice. The frequency of induced chromosome aberrations in spermatogonia is relatively low and spermatogonia cannot substitute bone marrow cells as a test system when assaying chemical mutagens.

Spermatogenic cells isolated from seminiferous tubules by enzymatic treatment are very sensitive to the action of Triton X-100. The cells isolated by mechanical dissociation of spermatogenic epithelium are destroyed during storage. On the contrary, the cell separation by sedimentation velocity technique in human serum protein gradient leads to cell stabilization. As the result, the cells in collected fractions kept their living capacity and, what is more, their specific features.

The sensitivity of spermatogonia of 101, TPS and CBA inbred mice to induction of chromosome damages by thiophosphamide (thioTEPA) was studied. With respect to sensitivity of bone marrow cells, these strains were ranked as follows: TPS greater than 101 greater than CBA. When used at the dose 2.25 mg/kg i/p thioTEPA induced chromosome damages in 11.4, 11.6 and 6.0% of spermatogonia of TPS, 101 and CBA mice, respectively. Thus, selection which increased sensitivity of bone marrow cells of TPS mice poorly affected germ cells. To obtain more correct estimations of genetically determined mouse strain sensitivity to chemical mutagens, the estimations should be based on frequencies of induced mutations in germ cells. The spectrum of mutations in spermatogonia differs from that in bone marrow cells: the frequencies of isochromatid breaks and symmetrical chromatid exchanges are higher in spermatogonia. This can be due to close situation of homologous chromosomes in interphase nuclei of spermatogonia.

Cyclophosphamide was given intraperitoneally in doses of 40, 80 and 160 mg/kg to C57BL/6 male mice. Cytogenetic effect in spermatogonia of A and B types and in pachytene spermatocytes was studied by the frequencies of chromosomes recorded in cells at the stage of diakinesis MI meiosis. In some cells cyclophosphamide induced structural chromosomal aberrations, including translocations and the disturbances of normal bivalent formation. The dose of 80 mg/kg induced translocations in spermatocytes with frequency 0.6% and appearance of 3% of translocation carriers in F1 generation. Three males were heterozygotes by the translocation of the Robertsonian type.

The data are presented in favour of nonthresholdness of the dose-effect relationships in exposure of mouse germ cells to chemical mutagens. The data were obtained by the method of dominant lethal mutations and by the analysis of specific locus mutations with single and fractionated treatment at different germ cell stages.