Healthy offspring from freeze-dried mouse spermatozoa held on the International Space Station for 9 months.

If humans ever start to live permanently in space, assisted reproductive technology using preserved spermatozoa will be important for producing offspring; however, radiation on the International Space Station (ISS) is more than 100 times stronger than that on Earth, and irradiation causes DNA damage in cells and gametes. Here we examined the effect of space radiation on freeze-dried mouse spermatozoa held on the ISS for 9 mo at -95 °C, with launch and recovery at room temperature. DNA damage to the spermatozoa and male pronuclei was slightly increased, but the fertilization and birth rates were similar to those of controls. Next-generation sequencing showed only minor genomic differences between offspring derived from space-preserved spermatozoa and controls, and all offspring grew to adulthood and had normal fertility. Thus, we demonstrate that although space radiation can damage sperm DNA, it does not affect the production of viable offspring after at least 9 mo of storage on the ISS.

Health, growth and reproductive success of mice exposed to environmentally relevant levels of Ra-226 via drinking water over multiple generations.

PURPOSE: To assess health, growth and reproductive success of mammals exposed for multiple generations to levels of radium-226 known to occur in environments surrounding uranium mines and mills in Canada. METHODS: The study consisted of a control group and four treatment groups each containing 40 mice (20 males and 20 females) of the CBA/CaJ strain that were continuously exposed to a range of radium-226 levels via drinking water. Breeding was at 8-10 weeks of age and the study was concluded after three breeding cycles. RESULTS: When compared to control mice, constant consumption of drinking water containing 0.012, 0.076, 0.78 and 8.0 Bq/l of radium-226 over four generations of mice did not demonstrably affect physical condition, weight, pregnancy rate, number of pups per litter, sex ratio and bodyweight gain of pups. Between generations, the observed differences in pregnancy rates that were noted in all groups, including controls, seemed to directly correlate with the weight and age of the females at breeding. CONCLUSIONS: Based on the endpoints measured on four generations of mice, there is no indication that the consumption of radium-226 via drinking water (at activity concentrations up to 8.0 Bq/l) affects health, growth and reproductive fitness.

Fukushima simulation experiment: assessing the effects of chronic low-dose-rate internal 137Cs radiation exposure on litter size, sex ratio, and biokinetics in mice.

To investigate the transgenerational effects of chronic low-dose-rate internal radiation exposure after the Fukushima Daiichi Nuclear Power Plant accident in Japan, 18 generations of mice were maintained in a radioisotope facility, with free access to drinking water containing (137)CsCl (0 and 100 Bq/ml). The (137)Cs distribution in the organs of the mice was measured after long-term ad libitum intake of the (137)CsCl water. The litter size and the sex ratio of the group ingesting the (137)Cs water were compared with those of the control group, for all 18 generations of mice. No significant difference was noted in the litter size or the sex ratio between the mice in the control group and those in the group ingesting the (137)Cs water. The fixed internal exposure doses were ∼160 Bq/g and 80 Bq/g in the muscles and other organs, respectively.

Radioadaptive response following in utero low-dose irradiation.

Acute radiation exposure is known to cause biological damage that leads to severe health effects. However, the effects and subsequent health implications of exposure to low doses of ionizing radiation are unclear. The purpose of this study was to investigate the effects of low-dose ionizing radiation exposures in utero. Pregnant laboratory mice (BALB/c) were exposed to low-dose Chernobyl radiation [10-13 mSv per day for 10 days] during organogenesis. The progeny were born and weaned in an uncontaminated laboratory, then were exposed to an acute radiation dose (2.4 Sv). Analysis of our end points (litter dynamics, DNA damage, bone marrow stem cell function, white blood cell counts and gene expression) suggests that a low-dose (100-130 mSv) in utero exposure to ionizing radiation is not deleterious to the offspring. Rather DNA damage, white blood cell levels, and gene expression results suggest a radioadaptive response was elicited for the in utero exposure with respect to the effects of the subsequent acute radiation exposure.

Evidence for mobile phone radiation exposure effects on reproductive pattern of male rats: role of ROS.

The relationship between radiofrequency electromagnetic fields emitted from mobile phone and infertility is a matter of continuing debate. It is postulated that these radiations may affect the reproduction pattern spell by targeting biochemistry of sperm. In an attempt to expedite the issue, 70 days old Wistar rats (n = 6) were exposed to mobile phone radiofrequency (RF) radiation for 2 h per day for 45 days and data compared with sham exposed (n = 6) group. A significant decrease (P < 0.05) in the level of testosterone and an increase in caspase-3 activity were found in the RF-exposed animals. Distortions in sperm head and mid piece of sperm mitochondrial sheath were also observed as captured by Transmission Electron Microscope (TEM). In addition, progeny from RF-exposed rats showed significant decreases in number and weight as compared with that of sham-exposed animals. A reduction in testosterone, an increase in caspase-3, and distortion in spermatozoa could be caused by overproduction of reactive oxygen species (ROS) in animals under mobile phone radiation exposure. Our findings on these biomarkers are clear indications of possible health implications of repeated exposure to mobile phone radiation.

In utero and early-life exposure of rats to a Wi-Fi signal: screening of immune markers in sera and gestational outcome.

An experimental approach was used to assess immunological biomarkers in the sera of young rats exposed in utero and postnatal to non-ionizing radiofrequency fields. Pregnant rats were exposed free-running, 2 h/day and 5 days/week to a 2.45 GHz Wi-Fi signal in a reverberation chamber at whole-body specific absorption rates (SAR) of 0, 0.08, 0.4, and 4 W/kg (with 10, 10, 12, and 9 rats, respectively), while cage control rats were kept in the animal facility (11 rats). Dams were exposed from days 6 to 21 of gestation and then three newborns per litter were further exposed from birth to day 35 postnatal. On day 35 after birth, all pups were sacrificed and sera collected. The screening of sera for antibodies directed against 15 different antigens related to damage and/or pathological markers was conducted using enzyme-linked immunosorbent assay (ELISA). No change in humoral response of young pups was observed, regardless of the types of biomarker and SAR levels. This study also provided some data on gestational outcome following in utero exposure to Wi-Fi signals. Mass evaluation of dams and pups and the number of pups per litter was monitored, and the genital tracts of young rats were observed for abnormalities by measuring anogenital distance. Under these experimental conditions, our observations suggest a lack of adverse effects of Wi-Fi exposure on delivery and general condition of the animals.

Effect of long-term exposure to a randomly varied 50 Hz power frequency magnetic field on the fertility of the mouse.

A double blind study on BALB/c mice was conducted to examine the effects of extremely low-frequency electromagnetic fields on fertility. The mice were continuously exposed or sham-exposed from conception for two generations to magnetic fields varying between 0.5 and 77 muT. Biological parameters related to fertility were evaluated. Serum testosterone levels and mass of testes and adrenals were determined. No significant difference was found between the sham-exposed and exposed groups for all the biological endpoints, except for sperm motility. A significant difference between the two groups was found prior to the swim-up test with quantitative analysis of sperm motility as well as after the swim-up test for quantitative and qualitative analysis of sperm motility. ELF-EMFs significantly decreased the number of living sperm and the quality of movement of sperm, although these adversities did not impact on the outcome of the other parameters investigated.

Paternal monoenergetic neutron exposure results in abnormal sperm, and embryonal lethality and transgenerational tumorigenesis in mouse F1 offspring.

Experiments were conducted to assay whether monoenergetic neutron-induced genetic damage in parental germline cells can give rise to development of cancer in the offspring. Seven-week-old C3H male mice were irradiated with monoenergetic neutrons with energy levels of 0.2 or 0.6 MeV at doses of 0, 50, 100 or 200 cGy. Two weeks after irradiation, when the male mice showed an increased incidence of sperm abnormalities, they were mated with virgin 9-week-old C57BL females. Litter size was decreased and embryo lethalities were increased in a dose-dependent manner. Furthermore, tumor incidence in male offspring born to male mice irradiated with 25 or 50 cGy at 0.6 MeV showed a tendency for increase as compared to the non-irradiated group value. Liver tumors in the 50 cGy group were significantly increased (P=0.03). It is concluded that the increased hepatic tumor risk in the F1 generation may have been caused by genetic transmission of some hepatoma-associated trait(s) induced by monoenergetic neutron irradiation.

Effects of a unique electromagnetic field system on the fertility of rats.

The authors investigated the fertility of male and female rats exposed to a unique-design electromagnetic apparatus (Hivex Electromagnetic Field System-5 [EMFS-5]), which establishes an omni-directional, spatial field and has a wide band range of 100 MHz-3 GHz. We used 32 male and 32 female rats that were proven breeders. Sixteen rats from each sex were exposed to the EMFS for 8h/day for 10 days. The others were sham exposed. The rats were divided into the following 4 groups: in group AG1-AG8, males and females were exposed; in group AG9-AG16, only females were exposed; in group AG17-AG24, only males were exposed; and in group AG25-AG32, males and females were sham exposed. After exposure for each group, a male rat was cohabited with a female rat until parturition. The authors' results showed that except for 1 male, the fertility of all other rats was not affected. They did not see differences in reproductive ability (latency to parturition, litter size, number of male/female pups, male-to-female ratio, mass of pups at weaning) between experimental groups and the sham exposed group. The authors concluded that exposure of male and female rats to the Hivex EMFS-5 does not affect fertility or reproductive ability.

Effect of low-intensity extremely high frequency radiation on reproductive function in wistar rats.

The exposure to low-intensity extremely high frequency electromagnetic radiation during spermatogenesis was accompanied by pathological changes, which resulted in degeneration and polymorphism of spermatozoa. The number of newborn rats increased in the progeny of irradiated animals.

Effect of high-frequency low-intensity irradiation on reproductive function in C57Bl/6 and randombred mice.

The effect of high-frequency low-intensity radiation on reproductive function was studied on C57Bl/6 and randombred mice. We revealed a progressive decrease in the number of offspring, prevalence of males over females in all generations, and the appearance of stillbirths. The decrease in the number of offspring was probably related to increased number of homozygotes and decreased number of heterozygotes in the population under the influence of nonthermal radiation.

[Reaction of posterity of two generations after exposure of pregnant Wistar rats to low dose irradiation during the period of fetus formation. Development of the first generation posterity]. / Posledstviia dlia potomstva dvukh pokolenii oblucheniia beremennykh samok-krys Vistar v malykh dozakh v period zakladki reproduktivnoi sistemy plodov. Razvitie potomstva pervogo pokoleniia.

Whole-body single exposure of female Wistar rats to 0.25, 0.5 and 1 Gy of gamma-rays (dose rate of 0.03 cGy/s) on the 10th day of pregnancy (a period of formation of the reproductive system in fetus) was carried out. To study irradiation consequences on the antenatal and postnatal development of the progeny 220 females, 700 19-day-old fetuses and about 1100 young rats were examined. The antenatal development of the progeny of the first generation was significantly impaired after the exposure to 1 Gy. However even less radiation doses resulted in a pronounced tendency to higher rates of intrauterine death and a lower number of live fetuses. Significant deviatins in the postnatal development of the first generation progeny were found after the exposure to 0.5 Gy, although the exposure to 0.25 Gy led to a higher rate of postnatal death and a less number of newborns in the litter.

Development of mouse testis and epididymis following intrauterine exposure to a static magnetic field.

In order to test if the in utero exposure to static magnetic fields affects testis and epididymis development in mice, females were exposed to 0.5-0.7 T, generated by a permanent magnet, from day 7 of gestation to the day of birth. No significant differences were found between exposed and sham-exposed animals with respect to body weight gain of dam during the gestational period, litter size, body weight of male pups at the day of birth, and body or testis-epididymis weight gain of pups from birth to day 35. Histopathologic evaluation of testis and epididymis of pups of 1, 5, 15, and 35 days of age showed no detectable alterations due to in utero exposure to static magnetic fields.

The influence of low doses 131I-induced maternal hypothyroidism on the development of rat embryos.

The aim of our research was to create and verify a model for studying the effects of a low dose of 131I and 131I-induced maternal hypothyroidism on the development of the embryo's thyroid gland and brain. The given dose (150 microCi) corresponds to the absorbed dose of 0.5 Gy. This dose is similar to that dose received by large numbers of the population of the C.I.S. regions polluted by radioactive isotopes of iodine as a result of the Chernobyl accident in 1985. Thirty-five female Wistar rats and their 168 newborn pups were used for observation. The females were divided into a control group and four experimental groups (each distinguished by the time of 131I injection: group I - no less than 12 days before mating; groups II, III and IV - on 5th, 10th and 16th days of gestation, respectively). In all the experimental female groups the incorporate dose of 131I led to hypothyroidism accompanied by a 43% reduction in the thyroxin level and by a nearly 8-fold increase in the TSH level. However, the influence of maternal hypothyroidism on the development of the thyroid gland and brain of embryos depends on the time when 131I took effect. There is a reduction in the weight of the newborns' brain and thyroid gland, total body mass. The hormonal status of the newborns' thyroid gland also changes. The proposed model will allow us to study many aspects of induced changes in the brain and thyroid gland of the embryos which develop under conditions of maternal hypothyroidism resulting from a low dose of 131I, administered at the critical times of development.

Developmental malformations and intrauterine deaths in gamma-ray-irradiated scid mouse embryos.

PURPOSE: To examine the induction by radiation of developmental malformations and intrauterine deaths in severe combined immunodeficiency (scid) mice. MATERIALS AND METHODS: The scid embryos, as well as those of C.B-17 control mice, were irradiated with graded doses of 60Co gamma-rays on gestation day 8. RESULTS: Intrauterine deaths in scid mice increased with radiation dose, and their frequency was substantially higher than in C.B-17 mice. The LD50 for intrauterine death in scid mice was 0.58 Gy and 1.25 Gy in C.B-17 mice. In addition, after irradiation scid mice showed several types of developmental malformations, including meningoencephalocele, spina bifida, eye defects, tail defects and oedema. Malformation incidences were higher in scid than in C.B-17 mice: 33.3% in scid mice irradiated with 0.75 Gy and 13.0% in C.B-17 mice irradiated with 1.0 Gy. However, when malformation incidences were plotted against intrauterine deaths, all the data, irrespective of the type of mouse, essentially fell along a single straight line. CONCLUSIONS: These results suggest that some mechanism common to both scid and normal mice induces developmental malformations. This mechanism involves cell killing. Residual DNA damage, such as double-strand breaks, could be associated with radiation-induced teratogenesis.

Maternal or paternal exposure to radiation increases susceptibility to the induction of glutathione S-transferase-positive hepatic foci in offspring rats.

Experiments were conducted to determine whether gamma-ray-induced genetic damage in parental rats can lead to the development of cancer in their offspring rats using glutathione S-transferase-positive (GST-P+) hepatic foci with or without the addition of diethylnitrosamine (DEN), a carcinogen. A single 1 Gy whole-body exposure of gamma-rays was given to pregnant rats at day 14 and during postnatal week 3, DEN was intraperitoneally injected twice in 1 week. Female pups from irradiated maternal and paternal rats were also used. Twelve weeks after birth, the rats were sacrificed. GST-P+ foci in animals subjected only to radiation were not different to those of normal control pups, but the incidence of GST-P+ foci was 2.4 times higher in pups treated with DEN alone at 3 weeks after birth than in those irradiated after the onset of pregnancy. In DEN-combined groups, irradiation of post-pregnant or maternal and paternal rats with gamma-rays before mating significantly increased both the incidence and area of GST-P+ foci when compared to those of rats treated with DEN alone. The proliferating cell nuclear antigen (PCNA) labeling index was significantly higher in the offspring of rats subjected to radiation alone or radiation combined with DEN than in normal control pups. Using a rat-liver model, the results of this study indicate that although the dose did not induce phenotypic malformation, exposure to radiation during the embryonic or pre-embryonic stage increases susceptibility to carcinogens.

Increased resorptions in CBA mice exposed to low-frequency magnetic fields: an attempt to replicate earlier observations.

This paper has two aims. First, it reports the findings of a study on the effects of low-frequency magnetic fields on reproduction. Second, it serves as an example of an attempt to replicate the results of an experimental study in an independent laboratory and discusses some of the problems of replication studies. To try to replicate the findings of a study reporting increased resorptions (fetal loss) in mice exposed to 20 kHz magnetic fields with sawtooth waveform and to study the possible effects of 50 Hz sinusoidal fields, pregnant mice were exposed to magnetic fields from day 0 to 18 of pregnancy, 24 h per day. The flux densities of the vertical magnetic fields were 15 microT (peak-to-peak) at 20 kHz and 13 or 130 microT (root mean square) at 50 Hz. Two strains of animals were used: CBA/S mice imported from the laboratory reporting the original observations, and a closely related strain CBA/Ca. The CBA/S mice were cleaned of pathogenic microbes and parasites before they were imported into our laboratory. The magnetic field exposures did not affect resorption rate in CBA/Ca mice. In CBA/S, the frequency of resorptions was higher in the exposed mice than in the control group. However, the increase was not significantly different from either the no-effect hypothesis or the results of the original study we were attempting to replicate. Differences between the two studies and difficulties in interpreting the results are discussed. It is concluded that the results tend more to support than argue against increased resorptions in CBA/S mice exposed to the 20 kHz magnetic field. The results demonstrate that animal strain is an important variable in bioelectromagnetics research: even closely related strains may show different responses to magnetic field exposure.

RF radiation-induced changes in the prenatal development of mice.

The possible effects of radiofrequency (RF) radiation on prenatal development has been investigated in mice. This study consisted of RF level measurements and in vivo experiments at several places around an "antenna park." At these locations RF power densities between 168 nW/cm2 and 1053 nW/cm2 were measured. Twelve pairs of mice, divided in two groups, were placed in locations of different power densities and were repeatedly mated five times. One hundred eighteen newborns were collected. They were measured, weighed, and examined macro- and microscopically. A progressive decrease in the number of newborns per dam was observed, which ended in irreversible infertility. The prenatal development of the newborns, however, evaluated by the crown-rump length, the body weight, and the number of the lumbar, sacral, and coccygeal vertebrae, was improved.

Sensitivity of reproducing sows and suckling pigs to stray voltage.

OBJECTIVE: To evaluate whether stray voltage reduces welfare of sows and their litters, causes reproductive problems, or impairs growth and survival of suckling pigs. ANIMALS: 120 gilts assigned randomly to 3 treatment groups: 2-V baseline plus 3-V pulses (2-5 V); 5-V baseline plus 3-V pulses (5-8 V); and control treatment (0-0 V). PROCEDURE: Behavior was recorded during gestation and lactation. Water and feed intakes were measured daily, milk composition was evaluated once during lactation, and hematocrit, hemoglobin, glucose, total protein, aspartate transaminase, alanine transaminase, albumin, globulins, and fatty acids values were measured at mating, weeks 8 and 15 of gestation, parturition, and weaning. Prolific ability of sows, mortality and disease of suckling pigs, and growth rate until 56 days of age were recorded. RESULTS: Gilts under voltage were lying down more often and performing less abnormal behaviors than were control gilts. Behavior of sows and suckling pigs was not affected by treatments. Water and feed intakes were similar among treatments, except during week 1 of lactation where feed intake was lower in the control group. Fecundity and prolific ability of sows, percentage of stillbirth, growth rate of suckling pigs, and milk composition were similar among treatments. More suckling pigs died in 2-5-V group than in other groups, but diarrhea was more frequent in the control group. Blood metabolites were similar among treatment groups. CONCLUSIONS: Transient stray voltage at values up to 8 V did not impair the welfare, reproductive performance, or health of sows and suckling pigs.

[The effect of chronic ionizing radiation at low doses on a number of reproductive indices in CC57W/Mv mice from an experimental Chernobyl population]. / Vliianie khronicheskogo ioniziruiushchego oblucheniia v malykh dozakh na riad pokazatelei reproduktivnoi funktsii myshei linii CC57W/Mv iz chernobyl'skoi éksperimental'noi populiatsii.

The effects of low doses of environmental ionizing radiation on reproductive functions of seven generations of CC57W/Mv mice from Chernobyl experimental population has been investigated. A decrease in the number of litters per female during reproductive period, the number of newborn animals per litter, and an increase in the postnatal mortality during the first month of life were shown. These effects are due to the stable disorders of parental reproductive system and the high level of in-vivo preimplantation deaths in F1--F7 generations of CC57W/Mv mice from the Chernobyl experimental populations.