Effect of antenatal action of Thio-Tepa on spermatogenesis of mature 101/N and CBA mice]

On pregnancy day 12 101/H and CBA mice were injected intraperitoneally 2.5 mg/kg bw thiophosphamide. 3.5-month-old male offspring were sacrificed. The drug effect on the testes was evaluated by karyologic analysis of the germ cell generations on stage 7 of the seminiferous epithelium cycle. A reliable reduction in the number of spermatogonia A, preleptotene and pachytene spermatocytes and spermatids at development stage 7 was found in 101/H mice. There were interspecific differences in spermatogenesis intensity in intact animals and recovery of germ cell pool after thiophosphamide action inducing toxicity.     

101/H line mice, a possible model of human chromosomal instability diseases

Chromosome aberrations were studied in cells of embryo liver of 101/H and CBA mice following mutagenic treatment with the alkylating agent--thiophosphamide. Higher sensitivity of chromosomes to aberration induction was found in 101/H mice. After crossing thiophosphamide treated 101/H and CBA males to untreated 101/H and CBA females, the lowest output of dominant lethal mutations was found in the progeny of 101/H females. It is suggested that the 101/H mice are a possible model of inherited diseases with chromosomal instability.     

Cytogenetic effect of mitomycin C and cytosine arabinoside on mice of different genotypes]

Cytogenetic effect of mitomycin C (MC) and cytosine arabinoside (CA) on bone marrow cells of male mice of the strains 101/HY, C57BL/6Y C,3H/SnY and of the (C3HX101) F1 hybrids was studied. The frequencies of cells with chromosome aberrations after the treatment with MC at a 5 mg/kg dose were 54,4%; 41,8%; 40,4% and 26,8% in 101H, B6, C3H/Sn mice and in the F1 hybrids (C3HX101) respectively. The frequencies of cells with chromosome aberrations after the treatment with CA at a 500 mg/kg dose were 25,2%; 17,8%; 10,8% and the 101/H, B6, C3H/Sn mice and in the F1 hybrids (C3HX101) respectively. Both mutagens induced the greatest number of chromosome aberrations in the 101/H strain and the smallest number in the F1 hybrid (C3HX101). A positive correlation was established between the levels of induced and spontaneous chromosome lesions.     

Strain-specific response in mice to the neonatal administration of ACTH(4-10) fragment: behavior, neurochemistry, and brain morphology

Neonatal injection of the ACTH4-10 fragment (5 micrograms daily for five days) caused genotype-dependent changes in concentrations of some monoaminergic neuromediators and their metabolites in hippocampus and brain stem of adult CBA and 101/HY mice. The catecholaminergic neurons increased in number in hypothalamic zona incerta of adult 101/HY mice. Neonatal injection of the peptide caused also genotype-dependent changes in the exploratory behavior of adult animals. Sound sensitivity was reduced in the 101/HY mice, whereas no sensitivity was revealed in both control and experimental groups of the CBA mice. The effects discovered were suggested to be caused by changes in neuronal differentiation.     

Spontaneous and induced chromosome aberrations in the bone marrow cells of different strains of mice during aging

Sensitivity of bone marrow cell chromosomes to alkylating agent thiophosphamide and to gamma-irradiation has been studied in the course of ageing in 101/H, A/He, CBA, BALB/c and C57BL/6 mice. The effects of both the kinds of mutagenic treatment and of the genotype of the animals on the age-dependent changes in sensitivity of bone marrow cell chromosomes were found. Following gamma-irradiation under our experimental conditions, no variation in the output of chromosomal aberrations was observed between the strains studied. Following thiophosphamide treatment, aged mice of strains 101/H, A/He and CBA showed an increased chromosome instability as compared to young ones. In C57BL/6 mice the level of induced chromosome aberrations was found to be age-independent. Following thiophosphamide treatment, cells with multiple chromosome lesions were found in the bone marrow. The higher instability of aged animals in some strains was mainly due to a sharp increase in the number of such cells. In the intact mice of all the strains studied no age-dependent increase in the number of cells showing structural chromosome aberrations was observed, while accumulation of aneuploid cells varied with genotype.     

Effect of thiophosphamide on the early period of gametogenesis in CBA, 101/H and AKR mice]

On the 12th day of pregnancy CBA, 101/H and AKR mice were given thiophosphamide in a dose of 5 mg/kg bw, and were sacrificed on the 19th day of pregnancy. The action of thiophosphamide on embryonal ovaries and testes was studied by assaying for the population of oocytes and relative number of the different stages of meiotic prophase I; index of the degeneration germ cells; for the population of prospermatogonies and their degeneration; morphometric study of nucleus of nucleolus of prospermatogonies. A significant decrease of germ cells was found in male and female embryos on the 19th day of pregnancy after thiophosphamide injection. Interspecific differences were found as regards the number of germ cells and their proportion in health as well as in response to a single antenatal injection of thiophosphamide.     

Relation of Infection to Tissue Temperature in Mice Infected with Mycobacterium marinum and Mycobacterium leprae

Intravenous and footpad infections with Mycobacterium marinum and footpad infections with M. leprae were compared in the following mouse strains: A/He, BALB/C, CBA, C3H, C57BL, C57L, DBA, 101, and CFW. The results varied a great deal according to mouse strain used. Intravenous injection of high doses of M. marinum resulted in deaths after 28 days of 100% of strain A/He, and none of strain 101; 27 days after injection, the feet and noses of all strain CBA mice, but few of the C57BL, 101, or CFW mice, were involved. Injection of a small dose of M. marinum into the footpad produced visible disease in 5 days in all of the C57BL and 101 mice, but in not more than 60% of the A/He, DBA, and CFW mice; the average amount of swelling at 17 days varied from 4.40 mm in strain C57L to 0.92 in strain 101. After footpad injection of M. leprae, the average plateau harvests varied from 1.3 x 10(7) acid-fast bacteria in strain CBA to 6.5 x 10(5) in strain C57L. The infections in CBA mice extended from the site of inoculation throughout the foot. The temperature was measured rectally, in the footpad, and in the tail. Analysis of all the results revealed little correlation among the three types of infection. There was a strong negative correlation between the tail temperature and the death rate after intravenous injection of M. marinum, and a strong positive correlation between footpad temperature and plateau harvest of M. leprae.     

Interstrain differences in the maturation of congenital reflexes in 101/HY and CBA mice in early postnatal ontogeny]

We have identified interstrain differences in the rate of formation of certain reflexes and parameters of physical development in CBA/LacSto and 101/HY mice. We have shown that in young 101/HY mice, the maturation of reflexes reflecting the development of the vestibular, neurosensory, and neuromuscular systems, such as surface righting, bar holding, negative geotaxis, and auditory startle response, takes place later during postnatal life. Opening of eyes and auditory canals in mice of all studied groups takes place at the same time. In CBA females, maturation of cliff avoidance reflex occurs later than in 101/HY females; hair also appeared later. Body weight of young 101/HY mice of both sexes is significantly higher during the period of postnatal development from day 2 to day 20 than in the CBA strain. However, the relative brain weight was lower in the 101/HY strain. CBA males had a higher brain weight and also showed a faster rate of formation of inborn reflexes. We discuss possible factors underlying the observed difficulties in the rate of formation of reflexes in 101/HY and CBA young mice in relation to general background information about their genetic and neurobehavioral features. The results provide evidence that these differences are genetically determined; the rate of reflex formation does not depend on the overall physical development of mice and is rather due to a delay and/or abnormalities in nervous system development.     

The effect of prodigiozan on the postradiational recovery of hemopoiesis in long-term bone morrow cultures of mice of different genotypes

The influence of prodigiozan on the processes of postirradiation recovery of hemopoiesis in long-term bone morrow cultures of two strain mice, having genetic distinctions in the condition of systems of the reparation DNA was investigated. It was showh, that the irradiation of long-term bone morrow cultures of mice reparation-defective strain 101/H resulted in the greater degree damage of early haemopoietic precursors (GM-CFC), reduction of the amount of the immature and of the mature granulocytes and of the decrease of the number of stromall cells in the comparison with the bone morrow of reparation-capable mice (CBA x C57B1)F1. Under the introduction in cultures of prodigiozan for 24 hours prior to an radiation the distinctions of the speed of postirradiation recovery of hemopoiesis substantially smoothed out, and the protective effect of the drag in bone morrow cultures of mice 101/H was comparable to those, marked in bone morrow cultures of reparation-capable strain mice (CBA x C57B1)F1. It is supposed, that this effect can be caused by the activation of the hematopoietic microenvironment cellular elements and inclusion of the mechanisms of intercellular of interactions, which provide stimulation of the regenerative processes at action radioprotective drags and can in the certain degree to compensate the defect of the systems of the reparation DNA.     

Genetic model of some human hereditary diseases: features of behavior, neurochemistry and morphology of the brain in mice of the 101/HY line

Studies of behavior, neurophysiological reactions, neuromediator synthesis and brain structure of mice of the 101/HY strain (including those of the authors) are reviewed. This mouse strain is characterized by a chromosomal instability because of a recessive mutation mutator-1 (mut-1) and the defective DNA excision repair. Experimental studies revealed a number of behavioral and neurological deviations in the 101/HY as compared to the CBA and the C3H strains. These are abnormalities in spatial orientation, altered fear and anxiety reactions, anomalous locomotion, seizure developing in response to agents of various nature, and disturbances of the central nervous system, both structural and biochemical. Genome instability results in a number of neurological mutations, that may lead to the phenotypical effects observed in the 101/HY mice. Since the 101/HY mice partially display signs of severe human hereditary diseases caused by chromosomal instability and defective DNA repair, they can serve as a promising genetic model for these and other diseases related to impairment of the central nervous system.     

Behavioral,Neurochemical, and Brain Morphology Features of the 101/HY Mice: A Genetic Model of Some Human Hereditary Diseases

Studies of behavior, neurophysiological reactions, neuromediator synthesis and brain structure of mice of the 101/HY strain (including those of the authors) are reviewed. This mouse strain is characterized by a chromosomal instability because of a recessive mutation mutator-1(mut-1) and the defective DNA excision repair. Experimental studies revealed a number of behavioral and neurological deviations in the 101/HY as compared to the CBA and the C3H mouse strains. These are abnormalities in spatial orientation, altered fear and anxiety reactions, anomalous locomotion, seizure developing in response to agents of various nature, and disturbances of the central nervous system, both structural and biochemical. Genome instability results in a number of neurological mutations, that may lead to the phenotypical effects observed in the 101/HY mice. Since the 101/HY mice partially display signs of severe human hereditary diseases caused by chromosomal instability and defective DNA repair, they can serve as a promising genetic model for these and other diseases related to impairment of the central nervous system.     

Ribosomal genes in inbred mouse strains: Interstrain and intrastrain variation of copy number and extent of methylation

Quantitative dot hybridization was used to estimate the rDNA copy number in brain tissues of five inbred mouse strains (AKR/JY, NZB/B1OrlY, CBA/CaLacY, 101/HY, and 129/JY), which were obtained from the collection of the Research Center of Biomedical Technologies (Y). In each strain, 9–12 mice aged 1–2 months were examined. The rDNA copy number per diploid genome in strains AKR (range 105–181, mean ± SD 136 ± 27) and NZB (129–169, 148 ± 12) was significantly lower than in strains CBA (172–267, 209 ± 31), 101 (179–270, 217 ± 30), and 129 (215–310, 264 ± 33). Mice of strain NZB were relatively homogeneous in this trait (CV = 8.1%). Strains AKR, CBA, 101, and 129 displayed significant between-group differences, CV varying from 12.5 to 19.9%. The same DNA specimens were digested with MspI or HpaII and used to estimate the extent of methylation of the 28S rDNA region. Regardless of the strain, all mice could be classed into two groups. One group (20 mice) had a methylated fraction accounting for less than 8% of rDNA and included all nine mice of strain NZB, seven out of nine mice of strain 101, and three out of ten mice of strain 129. In the other group (29 mice of strains AKR, CBA, 101, and 109), the methylated fraction varied from 18 to 38%. A possible role of methylation and the genome dosage of ribosomal genes in phenotypic variation (quantitative trait variation) of inbred mouse strains is discussed.     

Ribosomal genes in inbred mouse strains: interstrain and intrastrain variations of copy number and extent of methylation

Quantitative dot hybridization was used to estimate the rDNA copy number in brain tissues of five inbred mouse strains (AKR/JY, NZB/B1OrlY, CBA/CaLacY, 101/HY, and 129/JY), which were obtained from the collection of the Research Center of Biomedical Technologies (Y). In each strain, 9-12 mice aged 1-2 months were examined. The rDNA copy number per diploid genome in strains AKR (range 105-181, mean +/- SD 136 +/- 27) and NZB (129-169, 148 +/- 12) was significantly lower than in strains CBA (172-267, 209 +/- 31), 101 (179-270, 217 +/- 30), and 129 (215-310, 264 +/- 33). Mice of strain NZB were relatively homogeneous in this trait (CV = 8.1%). Strains AKR, CBA, 101, and 129 displayed significant between-group differences, CV varying from 12.5 to 19.9%. The same DNA specimens were digested with MspI or HpaII and used to estimate the extent of methylation of the 28S rDNA region. Regardless of the strain, all mice could be classed into two groups. One group (20 mice) had a methylated fraction accounting for less than 8% of rDNA and included all nine mice of strain NZB, seven out of nine mice of strain 101, and three out of ten mice of strain 129. In the other group (29 mice), the methylated fraction varied from 18 to 38%. A possible role of methylation and the genome dosage of ribosomal genes in phenotypic variation (quantitative trait variation) of inbred mouse strains is discussed.     

Molecular manifestations of radiation-induced genome instability: the possibility of chemical modification

The molecular manifestations of radiation-induced genome instability-changes of the DNA structure, the excision DNA repair and the contents of the reactive oxygen forms in bone marrow cells of the repair proficient mice (CBA) and of the repair-defective (101/H) lines in the dynamics up to 185 day after ionizing radiation exposure in the dose of 1.5 Gy were studied. Is was established, that after irradiation in bone marrow cells the descendants with the decreased activity of excision DNA repair and prone to increased changes of DNA structure DHK is arised. The injection of the phenozane in concentrations causing its receptor interaction with cells, did not defend DNA of the bone marrow cells from the radiation injury after the exposure in a sublethal dose, however it exerted influence on long-term changes. Due to the phenosane of the bone marrow cells of the irradiated mice of CBA line exhibited the larger activity in a DNA repair from damages and maintenance of vitality. The bone marrow cells of male mice of repair defective 101/H line, which phenozan was entered before the irradiation, remained unfit to the remuval of DNA damages by the repair, that probably resulted the activations of the program of the maintenance of genome constancy by the apoptosis in the cells--carriers of the structural defects and the cause of animal lethality.     

Structural abnormalities of hippocampus in 101/HY mice

We studied cytoarchitectonics of the hippocampus in 101/HY and CBA mice on brain sections stained after Nissl and Timm. In CBA mice, the structure of hippocampus was normal. In 10/HY mice, stratum pyramidale in field CA3 was "splitted" and the density of pyramidal neurons was decreased. Abnormalities were also found in the zone of suprapyramidal projections of mossy fibers (sp-ME), i.e., terminals of axons of the fascia dentata granular cells on the apical dendrites of pyramids. If in CBA mice the sp-MF zone was normal, i.e., looked like a vast compact formation or dense ordered bundle, in 101/HY mice, the sp-MF zone represented a group of scattered, diffuse, and interrupted bundles of varying length, some of which were incorporated in stratum pyramidale. Possible causes of the described morphological abnormalities are discussed, as well as their relation to specific features of biology, behavior, and neurological status of 101/HY mice.     

Lethality in LPS-induced endotoxemia in C3H/HeCr mice is associated with prevalence of proinflammatory cytokines: lack of protective action of lactoferrin

C3H/HeCr mice are more susceptible to infection compared with other strains. Lactoferrin (LF), a protein involved in innate defense, was shown to protect mice against lethal endotoxemia. In this investigation we attempt to explain the cause of increased susceptibility of C3H/HeCr mice to LPS and lack of protective LF action in these mice. We found that C3H/HeCr mice produced up to 5-fold more serum TNFalpha and 66% higher IFNgamma levels in response to i.v. LPS injection than the control, CBA strain. 24 h pretreatment of C3H/HeCr mice with LF did not cause inhibition of the LPS-induced TNFalpha serum levels, whereas in CBA mice LF significantly decreased TNFalpha level. IL-6 serum levels, in turn, were lowered in C3H/HeCr mice but elevated in CBA mice. That differential regulation of cytokine production by LF in C3H/HeCr mice paralleled a decreased survival after lethal LPS injection - 10% vs. 60% in control, PBS treated mice. In addition, determination of colony forming units (CFU) in livers and spleens after administration of 10(8) Escherichia coli revealed that pretreatment of CBA mice with LF caused a marked reduction of CFU in these organs, whereas in C3H/HeCr mice the changes were insignificant. These results indicate that the altered TNFalpha/IL-6 ratio in C3H/HeCr mice, as compared to control CBA mice, as well as the increased IFNgamma level, may be responsible for the increased susceptibility to endotoxemia in that substrain. We also suggest that an association exists between the LF protective effect against endotoxic sequelae and the insult-induced systemic immune response.     

Morphine-modulated mast cell migration and proliferation during early stages of zymosan-induced peritonitis in CBA mice

We have previously shown that supplementation of inflammation-inducing zymosan with a high dose ofmorphine inhibits peritoneal influx ofleukocytes in Swiss, C57C3H, Balb/c, and C57BL/6 strains but not in CBA mice. We have also reported that the different pattern of the response to morphine treatment might be, at least partially, due to the inter-strain differences in the peritoneal mast cell (P-MC) number (high in CBA mice versus other strains) and P-MC specific features (high sensitivity to degranulation upon morphine treatment in CBA mice). The aim of the present study was to investigate the mechanism of morphine action on P-MC in CBA mice. In particular, the effects of morphine on the proliferation and migration of P-MC in CBA mice with ongoing zymosan-induced peritonitis modulated by morphine were studied. Morphine alone acted as a strong chemoattractant for P-MC of CBA mice and this effect was opioid receptor-independent. Moreover, flow cytometric analysis showed that i.p. morphine injection induced significant proliferation of P-MC in CBA mice. Therefore, we conclude that the lack of anti-inflammatory effects of morphine during peritonitis in CBA mice might result not only from a unique sensitivity of CBA mast cells to morphine-induced degranulation but also from the fact that mast cell numbers increase at the inflammatory focus. The latter might be due to morphine-induced mast cell proliferation and/or migration.     

Vasoformative non-osteogenic (angio) sarcomas of bone-marrow stroma due to strontium-90.

In a series of experiments, mainly CBA/H, but also C2H/H, mice aged 3 months were injected intraperitoneally with solutions of 90Sr Cl2, the dose per mouse varying from 7 to 20 muCi, and compared with similar mice treated with 226Ra or 239Pu, discussed elsewhere. In male mice, the commonest tumour resulting at each dose of 90Sr was non-osteogenic (angio) sarcoma, a tumour not seen after 226Ra. In females, this tumour occurred far less frequently than osteosarcoma. In CBA mice of both sexes converted to radiation chimaeras (which are sterile) and similarly treated with 90Sr, the only skeletal tumours were osteosarcomas. When only half the body of CBA mice was X-irradiated with 1000 rad and the mice given 90Sr, non-osteogenic sarcoma occurred predominantly in those mice X-irradiated in the cephalic half. The results suggest that intact testes may provide co-factors for this type of neoplasm, whereas others have shown that oestrogens facilitate murine osteosarcoma. The non-osteogenic osteosarcomas arise from damaged stromal elements in bone-marrow of selected bones. The risk to this component of bone-marrow, as well as to haematopoietic tissue, should be considered in radiation protection.     

Radiation-induced mutation at tandem repeat DNA Loci in the mouse germline: spectra and doubling doses

The spectra and dose response for mutations at expanded simple tandem repeat (ESTR) loci in the germline of male mice acutely exposed to low-LET X or gamma rays at pre-meiotic stages of spermatogenesis were compared in five strains of laboratory mice. Most mutation events involved the gain or loss of a relatively small number of repeat units, and the distributions of length changes were indistinguishable between the exposed and control males. Overall, a significant bias toward gains of repeats was detected, with approximately 60% of mutants showing gains. The values for ESTR mutation induction did not differ substantially between strains. The highest values of doubling dose were obtained for two genetically related strains, BALB/c and C.B17 (mean value 0.98 Gy). The estimates of doubling dose for three other strains (CBA/H, C57BL/6 x CBA/H F1 and 129SVJ x C57BL/6) were lower, with a mean value of 0.44 Gy. The dose response for ESTR mutation across all five strains was very close to that for the specific loci (Russell 7-locus test). The mechanisms of ESTR mutation induction and applications of this system for monitoring radiation-induced mutation in the mouse germline are discussed.     

Structural Abnormalities of Hippocampus in 101/HY Mice

We studied cytoarchitectonics of the hippocampus in 101/HY and CBA mice on brain sections stained after Nissl and Timm. In CBA mice, the structure of hippocampus was normal. In 101/HY mice, stratum pyramidale in field CA3 was splitted and the density of pyramidal neurons was decreased. Abnormalities were also found in the zone of suprapyramidal projections of mossy fibers (sp-MF), i.e., terminals of axons of the fascia dentata granular cells on the apical dendrites of pyramids. If in CBA mice the sp-MF zone was normal, i.e., looked like a vast compact formation or dense ordered bundle, in 101/HY mice, the sp-MF zone represented a group of scattered, diffuse, and interrupted bundles of varying length, some of which were incorporated in stratum pyramidale. Possible causes of the described morphological abnormalities are discussed, as well as their relation to specific features of biology, behavior, and neurological status of 101/HY mice.