Let M be a tame mouse modelling $\mathrm {ZFC}$. We show that M satisfies “$V=\mathrm {HOD}_x$ for some real x”, and that the restriction $\mathbb {E}^M\!\upharpoonright \![\omega _1^M,\mathrm {OR}^M)$ of the extender sequence $\mathbb {E}^M$ of M to indices above $\omega _1^M$ is definable without parameters over the universe of M. We show that M has universe $\mathrm {HOD}^M[X]$, where $X=M|\omega _1^M$ is the initial segment of M of height $\omega _1^M$ (including $\mathbb {E}^M\!\upharpoonright \!\omega _1^M$), and that $\mathrm {HOD}^M$ is the universe of a premouse over some $t\subseteq \omega _2^M$. We also show that M has no proper grounds via strategically $\sigma $-closed forcings. We then extend some of these results partially to non-tame mice, including a proof that many natural $\varphi $-minimal mice model “$V=\mathrm {HOD}$”, assuming a certain fine structural hypothesis whose proof was almost established in Closson [1], and has since been completed in the preprint [14].

Boric acid (BA) is an important mineral for plants, animals and humans that assists metabolic function and has both positive and negative effects on biological systems. The present study aimed to investigate the effects of different concentrations of BA added to the culture media, the quality and in vitro development potential of mouse embryos. Superovulated C57Bl6/6j female mice were sacrificed ∼18 hours after human chorionic gonadotropin (hCG) injection. Single-cell-stage embryos were collected from the oviduct, divided into experiment groups and cultured in embryo medium with supplemented BA+ in 5% CO2 at 37 °C until 96 hours at the blastocyst stage. The blastocyst development rates of 0, 1.62 × 10−1, 1.62 × 10−2, 1.62 × 10−3 and 1.62 × 10−4 µM BA were 51.52%, 73.47%, 77.36% and 81.13%, respectively. The in vitro development rates were significantly higher in the 1.62 × 10−3 (p < 0.05) and 1.62 × 10−4 µM BA groups than in the control group (p < 0.001). These results indicated that low BA doses influenced embryo development by positively affecting in vitro development rates, embryo cell numbers, biochemical parameters and development at the molecular level by pluripotent and antioxidant genes. Therefore, BA seems to play an important role on in vitro embryo development.

Let M be a short extender mouse. We prove that if $E\in M$ and $M\models $“E is a countably complete short extender whose support is a cardinal $\theta $ and $\mathcal {H}_\theta \subseteq \mathrm {Ult}(V,E)$”, then E is in the extender sequence $\mathbb {E}^M$ of M. We also prove other related facts, and use them to establish that if $\kappa $ is an uncountable cardinal of M and $\kappa ^{+M}$ exists in M then $(\mathcal {H}_{\kappa ^+})^M$ satisfies the Axiom of Global Choice. We prove that if M satisfies the Power Set Axiom then $\mathbb {E}^M$ is definable over the universe of M from the parameter $X=\mathbb {E}^M\!\upharpoonright \!\aleph _1^M$, and M satisfies “Every set is $\mathrm {OD}_{\{X\}}$”. We also prove various local versions of this fact in which M has a largest cardinal, and a version for generic extensions of M. As a consequence, for example, the minimal proper class mouse with a Woodin limit of Woodin cardinals models “$V=\mathrm {HOD}$”. This adapts to many other similar examples. We also describe a simplified approach to Mitchell–Steel fine structure, which does away with the parameters $u_n$.

Electromagnetic radiation (EMR) has deleterious effects on sperm motility and viability, as well as oocyte membrane and organelle structure. The aim was to assess the effects of cell phone radiation on preimplantation embryo morphokinetics and blastocyst viability in mice. For superovulation, 20 female mice were treated with intraperitoneal (IP) injections of 10 IU pregnant mare’s serum gonadotropin (Folligon® PMSG), followed by 10 IU of human chorionic gonadotropin (hCG) after 48 h. The zygotes (n = 150) from the control group were incubated for 4 days. The experimental zygotes (n = 150) were exposed to a cell phone emitting EMR with a frequency range 900–1800 MHz for 30 min on day 1. Then, all embryos were cultured in the time-lapse system and annotated based on time points from the 2-cell stage (t2) to hatched blastocyst (tHDyz), as well as abnormal cleavage patterns. Blastocyst viability was assessed using Hoechst and propidium iodide staining. Significant increases (P < 0.05) were observed in the cleavage division time points of t2, t8, t10, and t12 of the experimental group compared with the controls. In terms of blastocyst formation parameters, a delay in embryo development was observed in the experimental group compared with the controls. Data analysis of the time intervals between the two groups showed a significant difference in the s3 time interval (P < 0.05). Also, the rates of fragmentation, reverse cleavage, vacuole formation, and embryo arrest were significantly higher in the experimental group (P < 0.05). Furthermore, the cell survival rate in the experimental group was lower than the control group (P < 0.05). Exposure to EMR has detrimental consequences for preimplantation embryo development in mice. These effects can manifest as defects in the cleavage stage and impaired blastocyst formation, leading to lower cell viability.

Hypercholesterolaemia is a major risk factor for CVD. Fish intake is associated with lower risk of CVD, whereas supplementation with n-3 long-chain PUFA (LC-PUFA) has little effect on the cholesterol concentration. We therefore investigated if cetoleic acid (CA), a long-chain MUFA (LC-MUFA) found especially in pelagic fish species, could lower the circulating total cholesterol (TC) concentration in rodents. A systematic literature search was performed using the databases PubMed, Web of Science and Embase, structured around the population (rodents), intervention (CA-rich fish oils or concentrates), comparator (diets not containing CA) and the primary outcome (circulating TC). Articles were assessed for risk of bias using the SYRCLE’s tool. A meta-analysis was conducted in Review Manager v. 5.4.1 (the Cochrane Collaboration) to determine the effectiveness of consuming diets containing CA-rich fish oils or concentrates on the circulating TC concentration. Twelve articles were included in the systematic review and meta-analysis, with data from 288 rodents. Consumption of CA-rich fish oils and concentrates resulted in a significantly lower circulating TC concentration relative to comparator groups (mean difference −0·65 mmol/l, 95 % CI (−0·93, −0·37), P < 0·00001), with high statistical heterogeneity (I2 = 87 %). The risk of bias is unclear since few of the entries in the SYRCLE’s tool were addressed. To conclude, intake of CA-rich fish oils and concentrates prevents high cholesterol concentration in rodents and should be further investigated as functional dietary ingredients or supplements to reduce the risk for developing CVD in humans.

In this paper we describe the existence and consequences of subspecific and individual variation in the genetic make-up of house mice. The purpose is to illustrate forms of variation that are often neglected in discussions about animal care and experimental design. Towards this end, different inbred mouse strains as well as genetically selected mouse lines are compared in relation to their ecological origin. Firstly, the behaviour of BALB/c, C57BL/6J and CBA mice is described in relation to different habitats. Furthermore, their aggression is compared, as measured by two paradigms. It appears that some inbred lines (eg BALB/c and C57BL/6J) clearly show behaviour that reflects the functional adaptation to the natural habitats in which their ancestors lived. Other strains (eg CBA) show a lack of such behavioural adaptation and their phenotypes appear to be very unstable over time. Secondly, two fundamentally different characters, both present in populations of wild house mice and under genetic control, are described: on the one hand, active copers are characterized by aggressive behaviour; on the other hand, passive copers are reluctant to attack. The active, aggressive animals (manipulators) are well adapted to an invariant environment like their own territory, whereas the passive, non-aggressive copers (adjustors) are well adapted to a changing environment, eg when roaming. We discuss to what extent these coping styles are present in laboratory strains of mice. The major conclusion with regard to both phenomena is that individual and subspecific variation may have significant implications for experimental design and the welfare of the experimental animals.

The present experiment compared the fear-related behaviour of a mouse strain selected over 101 generations for high litter size with that of a randomly selected strain. The H-strain, selected for large litter size, has a mean (± SD) litter size at birth of 21.5 ± 3.5 pups. The randomly bred C-strain has a mean (± SD) litter size of 9.6 ± 2.2 pups. The elevated plus-maze, the light:dark test and a resident:intruder test were used to measure how the mice responded to novelty. In the elevated plus-maze, a well-validated model of animal anxiety, the H-strain was significantly more anxious (having a lower percentage of entries into open arms) than the C-strain at 9 weeks of age. In the light: dark test, in which the light levels were similar to those in the home environment, the H-strain did not differ significantly from the C-strain in its avoidance of the brightest area. In the resident: intruder test, where aggression-trained, older H-strain males were the residents, 11-week-old intruding mice of the C-strain spent a higher percentage of their time in flight and immobility than intruders of the H-strain. There were clear anxiety- and fear-related differences between the strains, which may be related to their selection history. The results illustrate a need for further studies on the consequences of selection for increased production for the ability of animals to adapt to their home environment and cope with environmental changes.

Housing conditions can alter both the physiology and behaviour of laboratory animals. Forced-air-ventilated micro-isolation systems increase the efficient use of space, decrease the incidence of disease among laboratory rodents, and provide better working conditions for animal care staff; however, such systems can increase breeding variability and mortality. We examined the possibility that stressors associated with automated housing conditions evoke subtle changes among immune, endocrine, and behavioural parameters in mice housed in a static versus a forced-air-ventilated micro-isolation system. In addition, we assessed the effects of housing in the forced-air-ventilated micro-isolation system both with and without the use of an automatic watering system. Housing in the forced-air-ventilated micro-isolation system, using the automatic watering system, suppressed delayed-type hypersensitivity (DTH) responses, a measure of cell mediated immune function, compared with the responses of mice housed in static cages. Hypothalamic–pituitary–adrenal axis function was also altered by housing in the forced-air-ventilated micro-isolation system with the use of the automatic watering system, such that mice in this housing system had lower resting corticosterone concentrations and increased reactivity to restraint. Despite these changes in corticosterone, housing condition did not alter activity level or exploratory, anxiety-like, or depressive-like behaviours. These results suggest that investigators should carefully consider housing conditions in studies of immune and endocrine function.

Environmental light-dark cycles play an important role in behavioural and physiological processes. It is essential that laboratory vivaria be designed to properly control the light conditions in which laboratory mice are housed; however, this is not universally the case. Some laboratory vivarium doors are designed with windows, which allow light from the hallways to leak into the housing space during the rodents’ dark phase. Personnel entering and exiting the housing space during the dark phase can also create excessive light leak from brightly illuminated hallways. In this study, we investigated the hypothesis that exposure to dim light at night, as commonly experienced in many laboratory rodent housing spaces, alters mouse (Mus musculus) behaviour. We specifically analysed patterns of locomotor activity, anxiety- and depressive-like responses. Exposure to dim (5 lux) light at night altered home-cage locomotor activity and increased anxiety and some depressive responses among laboratory mice. These results suggest that light conditions can alter mouse behaviour and potentially influence experimental outcomes. Increased care should be taken to properly control light-dark conditions for laboratory animals.

A high circulating cholesterol concentration is considered an important risk factor for the development of CVD. Since lean fish intake and fish protein supplementation have been associated with lower cholesterol concentration in some but not all clinical studies, the main aim of this study was to investigate the effect of diets containing proteins from fish muscles and fish by-products on the serum/plasma total cholesterol (TC) concentration in rodents. A systematic literature search was performed using the databases PubMed, Web of Science and Embase, structured around the population (rodents), intervention (type of fish and fraction, protein dose and duration), comparator (casein) and the primary outcome (circulating TC). Articles were assessed for risk of bias using the SYRCLE’s tool. A meta-analysis was conducted in Review Manager v. 5·4·1 (the Cochrane Collaboration) to determine the effectiveness of proteins from fish on the circulating TC concentration. Thirty-nine articles were included in the systematic review and meta-analysis, with data from 935 rodents. The risk of bias is unclear since few of the entries in the SYRCLE’s tool were addressed. Consumption of proteins from fish resulted in a significantly lower circulating TC concentration when compared with control groups (mean difference −0·24 mmol/l, 95 % CI − 0·34, −0·15, P < 0·00001), with high statistical heterogeneity (I2 = 71 %). To conclude, proteins from fish muscles and by-products show promise as a functional dietary ingredient or supplement by preventing high cholesterol concentration in rodents, thus reducing one of the most important risk factors for developing CVD.

We show that in many extender models, e.g., the minimal one with infinitely many Woodin cardinals or the minimal with a Woodin cardinal that is a limit of Woodin cardinals, there are no generic embeddings with critical point $\omega _1$ that resemble the stationary tower at the second Woodin cardinal. The meaning of “resemble” is made precise in the paper (see Definition 0.3).

Somatic cell nuclear transfer (NT) is associated with aberrant changes in epigenetic reprogramming that impede the development of embryos, particularly during zygotic genome activation. Here, we characterized epigenetic patterns of H3K4me3, H3K9me3, and H3K27me3 in mouse NT embryos up to the second cell cycle (i.e. four-celled stage) during zygotic genome activation. In vivo fertilized and parthenogenetically activated (PA) embryos served as controls. In fertilized embryos, maternal and paternal pronuclei exhibited asymmetric H3K4me3, H3K9me3, and H3K27me3 modifications, with the paternal pronucleus showing delayed epigenetic modifications. Higher levels of H3K4me3 and H3K9me3 were observed in NT and PA embryos than in fertilized embryos. However, NT embryos exhibited a lower level of H3K27me3 than PA and fertilized embryos from pronuclear stage 3 to the four-celled stage. Our finding that NT embryos exhibited aberrant H3K4me3, H3K9me3, and H3K27me3 modifications in comparison with fertilized embryos during early zygotic genome activation help to unravel the epigenetic mechanisms of methylation changes in early NT reprogramming and provide an insight into the role of histone H3 in the regulation of cell plasticity during natural reproduction and somatic cell NT.

Polycystic ovary syndrome (PCOS) is a complex disorder and genetic factors are believed to play a role. The main aim was to investigate expression levels of genes involved in PI3K/AKT signalling pathway pretreatment and post-treatment. Mouse models of PCOS were generated. Group one included control mice with no polycystic ovaries (n = 4), Group 2 included a PCOS mouse model (n = 8), Group 3 included PCOS mice treated with clomiphene citrate (n = 7) and Group 4 included PCOS mice treated with clomiphene citrate, metformin and pioglitazone (n = 8). Histochemical analyses were performed. Total RNA was extracted and cDNA was synthesized. Irs, Akt1 and Akt2, mTor and Pdpk1 gene expression levels were evaluated by RT-PCR amplification. In Group 1, cortex and medulla were evaluated as normal; in Group 2, ovarian cortex was composed of immature oocytes and cystic follicles with atretic follicles. In Groups 3 and 4, follicles were in the process of normal follicle differentiation. The expression levels of Akt1 and Pi3k were significantly different (P < 0.0001) between Groups 1 and 2. The significant differences in expression levels of Pi3k and Akt1 were also observed between the Group 1 and both Groups 3 and 4 (P < 0.0001). Furthermore, significant variations of the expression levels of mTor between Groups 1 and 4 were observed. The extrapolation of results of this study may imply that follicular development may be regulated by molecular pathways involving Pi3k, Akt1 and mTor expression. Therefore, genes in the PI3K/AKT pathway may have a direct regulatory role in the development of PCOS.

Methomyl is a broad-spectrum carbamate insecticide that has a variety of toxic effects on humans and animals. However, there have been no studies on the toxicity of methomyl in female mammalian oocytes. This study investigated the toxic effects of environmental oestrogen methomyl exposure on mouse oocyte maturation and its possible mechanisms. Our results indicated that methomyl exposure inhibited polar body extrusion in mouse oocytes. Compared with that in the control group, in the methomyl treatment group, superoxide anion free radicals in oocytes were significantly increased. In addition, the mitochondrial membrane potential of metaphase II stage oocytes in the methomyl treatment group was significantly decreased, resulting in reduced mouse oocyte quality. After 8.5 h of exposure to methomyl, metaphase I stage mouse oocytes displayed an abnormal spindle morphology. mRNA expression of the pro-apoptotic genes Bax and Caspase-3 in methomyl-treated oocytes increased, which confirmed the apoptosis. Collectively, our results indicated that mouse oocyte maturation is defective after methomyl treatment at least through disruption of spindle morphology, mitochondrial function and by induction of oxidative stress.

The quality and quantity of a spermatogonial stem-cell (SSC) culture can be measured in less time using a 3D culture in a scaffold. The present study investigated stemness gene expression and the morphological and structural characterization of SSCs encapsulated in alginate. SSCs were harvested from BALB/c neonatal mice testes through two-step mechanical and enzymatic digestion. The spermatogonial populations were separated using magnetic-activated cell sorting (MACS) using an anti-Thy1 antibody and c-Kit. The SSCs then were encapsulated in alginate hydrogel. After 2 months of SSC culturing, the alginate microbeads were extracted and stained to evaluate their histological properties. Real-time polymerase chain reaction (PCR) was performed to determine the stemness gene expression. Scanning electron microscopy (SEM) was performed to evaluate the SSC morphology, density and scaffold structure. The results showed that encapsulated SSCs had decreased expression of Oct4, Sox2 and Nanos2 genes, but the expression of Nanog, Bcl6b and Plzf genes was not significantly altered. Histological examination showed that SSCs with pale nuclei and numerous nucleolus formed colonies. SEM evaluation revealed that the alginate scaffold structure preserved the SSC morphology and density for more than 60 days. Cultivation of SSCs on alginate hydrogel can affect Oct4, Sox2 and Nanos2 expression.

While metabolic disorders such as obesity and diabetes are costly and deadly to the current population, they are also extremely detrimental to the next generation. Much of the current literature focuses on the negative impact of poor maternal choices on offspring disease, while there is little work examining maternal behaviors that may improve offspring health. Research has shown that voluntary maternal exercise in mouse models improves metabolic function in offspring. In this study, we hypothesized that controlled maternal exercise in a mouse model will effect positive change on offspring obesity and glucose homeostasis. Female mice were separated into three groups: home cage, sedentary, and exercise. The sedentary home cage group was not removed from the home cage, while the sedentary wheel group was removed from the cage and placed in an immobile wheel apparatus. The exercise group was removed from the home cage and run on the same wheel apparatus but with the motor activated at 5–10 m/min for 1 h/d prior to and during pregnancy. Offspring were subjected to oral glucose tolerance testing and body composition analysis. There was no significant difference in offspring glucose tolerance or body composition as a consequence of the maternal exercise intervention compared to the sedentary wheel group. There were no marked negative consequences of the maternal controlled exercise intervention. Further research should clarify the potential advantages of the controlled exercise model and improve experimental techniques to facilitate translation of this research to human applications.