Male Laboratory Mice Research Articles

Serotonin drives aggression and social behaviors of laboratory male mice in a semi-natural environment.

Aggression is an adaptive social behavior crucial for the stability and prosperity of social groups. When uncontrolled, aggression leads to pathological violence that disrupts group structure and individual wellbeing. The comorbidity of uncontrolled aggression across different psychopathologies makes it a potential endophenotype of mental disorders with the same neurobiological substrates. Serotonin plays a critical role in regulating impulsive and aggressive behaviors. Mice lacking in brain serotonin, due to the ablation of tryptophan hydroxylase 2 (TPH2), the rate-limiting enzyme in serotonin synthesis, could serve as a potential model for studying pathological aggression. Home cage monitoring allows for the continuous observation and quantification of social and non-social behaviors in group-housed, freely-moving mice. Using an ethological approach, we investigated the impact of central serotonin ablation on the everyday expression of social and non-social behaviors and their correlations in undisturbed, group-living Tph2-deficient and wildtype mice. By training a machine learning algorithm on behavioral time series, "allogrooming", "struggling at feeder", and "eating" emerged as key behaviors dissociating one genotype from the other. Although Tph2-deficient mice exhibited characteristics of pathological aggression and reduced communication compared to wildtype animals, they still demonstrated affiliative huddle behaviors to normal levels. Altogether, such a distinct and dynamic phenotype of Tph2-deficient mice influenced the group's structure and the subsequent development of its hierarchical organization. These aspects were analyzed using social network analysis and the Glicko rating methods. This study demonstrates the importance of the ethological approach for understanding the global impact of pathological aggression on various aspects of life, both at the individual and group levels. Home cage monitoring allows the observation of the natural behaviors of mice in a semi-natural habitat, providing an accurate representation of real-world phenomena and pathological mechanisms. The results of this study provide insights into the neurobiological substrate of pathological aggression and its potential role in complex brain disorders.

Histological and Physiological Evaluation of Salmonella Spp. Pathogenicity Experimentally Dosed in Male Albino Mice

The research aimed to isolate and diagnose the serological strains of Salmonella spp. that cause typhoid fever, as well as those that cause intestinal inflammations, and to study their histological pathogenesis after experimentally dosed in immunosuppressed male albino mice. The research included 180 blood and stool samples from people with typhoid fever, and 20 samples from people with diarrhea, as well as 30 samples representing the control group. The bacteriological results showed that 26 patients were diagnosed with S. typhi out of 180 patients with typhoid fever, representing 14.4%, and 5 patients were diagnosed with S. typhimurium out of 20 patients with diarrhea, representing 25%. The results of the study showed an increase in the levels of liver enzymes, as the average concentration of the ALT enzyme for the category of patients infected with typhoid, with a recent and confirmed infection with S. typhi, reached 11.283 international units/liter, and the average concentration of the AST enzyme for the same category reached 20.1 international units/liter, compared to the control group. 48 male laboratory mice were used and distributed into 4 groups of 12 mice per group. The first group was the control group that was dosed with physiological solution in an volume of 0.2 ml. The second group was dosed with a suspension of S. typhi bacteria in a volume of 0.2 ml and a concentration of 1×108 colonies/ml. The third group was dosed for a week with the immunosuppressant cyclosporine before and after the experimental infection with a suspension of S. typhi bacteria in a volume of 0.2 ml and a concentration of 1×108 colony/ml. The fourth group was dosed with a suspension of S. typhimurium bacteria in a volume of 0.2 ml and a concentration of 1×107 colony/ml. The mice were dissected one week, two weeks and three weeks after the experimental infection, at a rate of 3 mice per week from each group. The blood was collected and the liver was removed from each mouse. The results showed a slight increase in the ALT enzyme average concentration for the group of mice treated with the immunosuppressant cyclosporine and dosed with S. typhi, reaching 18.57 IU/L, while the group of mice dosed with S. typhimurium was within the limits of the control group and reached 12.24 IU/L. The AST enzyme concentration rate in the control group was 15.136 IU/L, and for the group of mice treated with the immunosuppressant cyclosporine and dosed with S. typhi, it reached 24.74 IU/L, while the concentration for the group of mice dosed with S. typhimurium reached 21.76 IU/L. As for the histological study, the results of the microscopic examination showed the occurrence of many histological lesions in the liver, represented by severe degeneration and acute necrosis, with hypertrophy and sometimes hyperplasia in the hepatocytes, and the loss of chromatin in the nuclei of a number of them, with thickening of the nuclear envelope and sometimes thickening of the nuclei, as well as vacuolation of the cytoplasm in other hepatocytes, with an increase in the number and size of Kupffer cells in the blood sinusoids, which varied in their appearance between narrowed, dilated and congested with blood. It was found that these pathological lesions were more severe in the group of mice treated with the immunosuppressant cyclosporine and dosed with S. typhi.

Microglia undergo molecular and functional adaptations to dark and light phases in male laboratory mice

Microglia are increasingly recognized to contribute to brain health and disease. Preclinical studies using laboratory rodents are essential to advance our understanding of the physiological and pathophysiological roles of these cells in the central nervous system. Rodents are nocturnal animals, and they are mostly maintained in a defined light–dark cycle within animal facilities, with many laboratories investigating the molecular and functional profiles of microglia exclusively during the animals’ light (sleep) phase. However, only a few studies have considered possible differences in microglial functions between the active and sleep phases. Based on initial evidence suggesting that microglial intrinsic clock genes can affect their phenotypes, we sought to investigate differences in transcriptional, proteotype and functional profiles of microglia between light (sleep) and dark (active) phases, and how these changes are affected in pathological models. We found marked transcriptional and proteotype differences between microglia harvested from male mice during the light or dark phase. Amongst others, these differences related to genes and proteins associated with immune responses, motility, and phagocytosis, which were reflected by functional alterations in microglial synaptic pruning and response to bacterial stimuli. Possibly accounting for such changes, we found RNA and protein regulation in SWI/SNF and NuRD chromatin remodeling complexes between light and dark phases. Importantly, we also show that the time of microglial sample collection influences the nature of microglial transcriptomic changes in a model of immune-mediated neurodevelopmental disorders. Our findings emphasize the importance of considering diurnal factors in studying microglial cells and indicate that implementing a circadian perspective is pivotal for advancing our understanding of their physiological and pathophysiological roles in brain health and disease.

Evaluation of Genotoxic Effects of Silver Nanoparticles on Bone Marrow Chromosome Aberrations in Laboratory Male Albino Mice Mus musculus

Evaluation of Genotoxic Effects of Silver Nanoparticles on Bone Marrow Chromosome Aberrations in Laboratory Male Albino Mice Mus musculus

Improved Memory and Lower Stress Levels in Male Mice Co-Housed with Ovariectomized Female Mice

Aggressiveness, expressed by fighting, is a frequent problem in group-housed laboratory male mice and results in increased stress, injury, and death. One way to prevent fighting is by pairing the male mice with ovariectomized female mice to provide a compatible companion. However, the effect of these housing conditions remains unclear. Therefore, we aimed to evaluate behavior and stress levels in two different housing conditions, pair-housed with an ovariectomized female and group-housed with other males. Behavioral tests were performed to assess stress and anxiety-like behavior. Moreover, the corticosterone levels in plasma were measured by ELISA. Based on home cage behavior assessment, pair-housed male mice showed no signs of fighting, not even after isolation and regrouping. Our results also showed that the pair-housed males had a better memory and demonstrated less anxiety-like behavior. Subsequently, the pair-housed male mice had a larger reduction in corticosterone levels compared to group-housed males. Overall, pair-housing reduced anxiety-like behavior and stress levels in male mice compared to standard group-housing.

Studying the Effect of nano-extract of Nerium Oleander Leaves on the Histological Structure of the Liver in Male Laboratory Mice

Objectives: The purpose of the research was to see how a nano-extract (zinc oxide) of oleander leaves affected the histological structure of the liver in male laboratory mice aged (7-8) weeks and weighing (28-35 g). Methods: They were split up into three groups, with ten mice in each. The control group made the first group. The second group was treated with an oleander leaf nano-extract at a concentration of (20 mg/kg). The group that was administered a 30 mg/kg dosage of oleander leaf nano-extract is the third group. For 30 to 45 days on a daily basis, a (30 mg/kg) concentration of the oleander leaf nano-extract was used. Half of the rodents were sacrificed at the end of the initial thirty days, and histological sections of the liver were obtained. Results: Histological sections of the liver were obtained from the residual half, which was sacrificed after 45 days when the experiment ended. Animals injected with a Nano-extract of oleander leaves at a dose of (20 mg/kg) for 40 days had aberrant liver structure, cells, and histological abnormalities. Animals that received a 45-day injection of a (30 mg/kg) dosage of oleander leaf nano-extract also had pathological alterations and aberrant liver and central vein cell morphology. Conclusions: The results showed the toxic effects of the Nano-extract of the oleander plant and the xistence of histological alterations in the histological structure of the liver in groups treated with varying amounts of oleander leaf nano-extract.

Bite Wounds and Dominance Structures in Male and Female African Spiny Mice (Acomys cahirinus): Implications for Animal Welfare and the Generalizability of Experimental Results.

Bite wounds due to aggression in male laboratory mice (Mus musculus) are a major welfare concern, often leading to attrition, chronic activation of the innate immune system, and significant impacts on the experimental results derived from the use of these animals as models. Bite wounding within the home-cage of spiny mice (Acomys cahirinus)-a valuable research model for wound healing and menstruation-is poorly characterized. While we have anecdotally observed frequent bite wounding in Acomys, the frequency of aggression within the home-cage, the severity of the bite wounds, and the types of dominance structures remain unstudied. Here, we report that 46% of Acomys cages in our colony had at least one bite wound over the course of a year and that same-sex pairs fought in the home-cage 10% of the time during their dark/active phase. Both sexes inflicted wounds and frequently engaged in agonistic behaviors, even with stable dominance structures. We found that females inflicted less severe bite wounds in same-sex housing. Also, aged females in same-sex pairs were never observed fighting, and no bite wounds were observed in aged Acomys. These results suggest that we should consider whether bite wounding negatively impacts our experimental results since physical trauma is known to alter menstrual cycling and healing.

The Effect of Phenolic Extract of Mint (Mentha spicata) in the Fertility of Male Laboratory Mice.

The current study was conducted to investigate the effect of the phenolic extract of the Mentha spicata plant on the fertility of laboratory mice. The phenolic compounds were extracted using the Reflex condenser from the leaves of the Mentha spicata plant, and it was chemically detected. In the current study,)Albino Mice of the musculus Mus type was used at an age ranging between (12-11) months. The group was randomly divided into three groups. The control group was injected with a physiological solution (0.9% NaCl), the second group was injected with the phenolic extract of the Mentha spicata plant at (100 mg/kg) concentration, and the third group was injected by concentration (200 mg/kg) from the phenolic extract of the Mentha spicata. The phenols were dissolved in a physiological solution (0.9% NaCl), and all individuals of these groups were injected through the peritoneal membrane I.P. at a rate of 0.5 ml per animal per day for 30 days. The phenolic extract of Mentha spicata leaves caused a significant decrease (P<0.05) in the level of Testosterone and Luteinizing hormone (ng/ml) in the blood serum of the first and second treatment group when compared with the control group. The study also indicates a significant decrease (P<0.05) in the concentration of Follicle-Stimulating Hormone in the third treatment group compared with its level in the control group. At the same time, there were no significant changes (P<0.05) for the second treatment group compared with the control group. The average concentration of sperms taken from the caudal epididymis did not change significantly (P<0.05) for both treatments compared to the control group. The percentage of motile sperm decreased significantly (P<0.05) as a result of treatment with the phenolic extract of Mentha spicata leaves, and this percentage is directly proportional to the increase in the doses used of the extract. Sperm vitality compared to the control group, as for the percentage leading to abnormal sperms, the results showed a significant increase (P<0.05) in the average percentage of abnormal sperms in the caudal epididymis of the second treatment animals when compared with the rates of the first and control groups, while there was no There were no significant changes (P<0.05) in the rate of the first treatment compared to the control. Histologically, the results indicate that treatment with phenolic extract of Mentha spicata leaves caused simple histological changes, represented by a simple vacuole of the interstitial layer between the tubules, slight congestion and partial detachment of the germ cells from the basement membrane with a thick fibrous capsule surrounding the epididymis tubes and congestion of blood vessels. In contrast, the seminal tubules and seminal lumen remained normal. This compared to the control group, which showed the semi- Bionatura http://dx.doi.org/10.21931/RB/CSS/2023.08.03.48 2 niferous tubules, seminal cavity and germ layers commonly with normal spermatozoa stages. Keywords: Phenolic extract, Mentha spicata, Fertility

Effects of prepubertal to peripubertal exposure of triclosan on the reproductive health of the young male laboratory mice

Over the last few decades, a massive increase in environmental toxicants has played a significant role in causing hindrance in the process of sexual maturity, leading to impaired reproductive health. Several toxicants are existing in the environment because of rapid industrialization, agricultural activities, and urbanization that act as endocrine disrupting chemicals (EDCs). Triclosan (TCS; 2,4,4’-trichloro-2’-hydroxydiphenyl ether) is one of the EDCs, acts as an antimicrobial chemical, and is used widely in personal care products and several commercial preparations as preservatives. It is found to interfere with normal reproduction and sexual maturity. The present study is therefore, aimed to investigate the impact of prepubertal to peripubertal exposure of TCS (300 and 600 mg/kg BW/day from PND 22 to PND 63) to observe the age of the onset of puberty, weights of the reproductive organs, alterations in the levels of testicular cholesterol, serum testosterone, and histopathology of the testis in the young laboratory mice. TCS exposure caused a significant delay in the age of prepuce separation, an indicator of the onset of puberty. Its exposure from PND 22 to PND 63 resulted in significant reductions in the weights of the testis, epididymis, and seminal vesicle, levels of testicular cholesterol, and serum testosterone in the young mice at PND 64. Testicular histology of such mice also showed regressive changes in the seminiferous tubules, indicating the interference of TCS in the process of spermatogenesis. The findings of the present study, therefore, reveal that TCS delays the age of onset of puberty and interferes with the endocrine functions of the testis.

Effect of hydrocortisone and olive oil on phagocytes

This study organized to realize the side effect of hydrocortisone therapy which administrated by thigh muscle injection on phagocytic cells, and inhibit their functions. Fifteen laboratory male white mice was distributed into three groups used in this study , each group consist of five animals . 1st group administrated by normal saline orally for ten days, while 2nd group injected in thigh muscle by 1mg/kg of the therapy for ten days, and the 3rd group injected in thigh muscle by 1mg/kg of the therapy for ten days then administrated orally by 0.5 ml / 100 g of olive oil for anther ten days.The Results of the study agree with other studies and investigate side effect of the therapy which cause inhibition to the activity of phagocytic cells and decrease in their number in 2nd group, whenever in 3rd group the study discover the benefit of olive oil to reactivate the whole of immune system and especially the phagocytic cells and increase their number.

Effects of clozapine-N-oxide and compound 21 on sleep in laboratory mice.

Designer receptors exclusively activated by designer drugs (DREADDs) are chemogenetic tools for remote control of targeted cell populations using chemical actuators that bind to modified receptors. Despite the popularity of DREADDs in neuroscience and sleep research, potential effects of the DREADD actuator clozapine-N-oxide (CNO) on sleep have never been systematically tested. Here, we show that intraperitoneal injections of commonly used CNO doses (1, 5, and 10 mg/kg) alter sleep in wild-type male laboratory mice. Using electroencephalography (EEG) and electromyography (EMG) to analyse sleep, we found a dose-dependent suppression of rapid eye movement (REM) sleep, changes in EEG spectral power during non-REM (NREM) sleep, and altered sleep architecture in a pattern previously reported for clozapine. Effects of CNO on sleep could arise from back-metabolism to clozapine or binding to endogenous neurotransmitter receptors. Interestingly, we found that the novel DREADD actuator, compound 21 (C21, 3 mg/kg), similarly modulates sleep despite a lack of back-metabolism to clozapine. Our results demonstrate that both CNO and C21 can modulate sleep of mice not expressing DREADD receptors. This implies that back-metabolism to clozapine is not the sole mechanism underlying side effects of chemogenetic actuators. Therefore, any chemogenetic experiment should include a DREADD-free control group injected with the same CNO, C21, or newly developed actuator. We suggest that electrophysiological sleep assessment could serve as a sensitive tool to test the biological inertness of novel chemogenetic actuators.

Mating-induced prolactin surge is not required for subsequent neurogenesis in male mice.

Parenting involves major behavioral transitions that are supported by coordinated neuroendocrine and physiological changes to promote the onset of novel offspring-directed behaviors. In comparison to maternal care, however, the mechanisms underlying the transition to paternal care are less understood. Male laboratory mice are predominantly infanticidal as virgins but show paternal responses 2 weeks after mating. Interestingly, males show a mating-induced surge of prolactin, which we hypothesized may be involved in initiating this behavioral transition. During pregnancy, prolactin stimulates olfactory bulb neurogenesis, which is essential for maternal behavior. Mating induces olfactory bulb neurogenesis in males, but it is unknown whether this is driven by prolactin or is important for subsequent paternal care. New olfactory neurons are generated from cells in the subventricular zone (SVZ) and take about 2 weeks to migrate to the olfactory bulb, which may account for the delayed behavioral change in mated males. We investigated whether mating increases cell proliferation at the SVZ. Males were either mated, exposed to receptive female cues, or left alone (control) and injected with Bromodeoxyuridine (BrdU, a marker of cell division). Contrary to our hypothesis, we found that mating decreased cell proliferation in the caudal lateral portion of the SVZ. Next, we tested whether prolactin itself mediates cell proliferation in the SVZ and/or new cell survival in the olfactory bulb by administering bromocriptine (prolactin inhibitor), vehicle, or bromocriptine + prolactin prior to mating. While suppressing prolactin had no effect on cell proliferation in the SVZ, administering exogenous prolactin resulted in significantly higher BrdU-labeled cells in mated but not virgin male mice. No effects of prolactin were observed on new olfactory cell survival. Taken together, prolactin may have context-dependent effects on new cell division in the SVZ, while other unknown mechanisms may be driving the effects on new olfactory cell survival following mating.

Evaluation of the effects of mobile phone electromagnetic radiation on some physiological parameters and histological structure in some laboratory male mice organs

Recently, the researcher has shown great interest in Electromagnetic radiation released from different devices such as TV, microwaves, medical apparatus, and satellites because of its effect on animals' growth and health. Exposure to "EMR" from mobiles phone can cause adverse effects on different cell functions. This study aimed to evaluate the effects of these radiations on histological and some blood parameters. The present study used 20 mice divided into two groups, the first one contains five animals as control, and the second experiment group contains 15 animals. EMR exposed from mobile for 12 h\day for one month. Histological examination of lungs, hearts and spleen showed a dramatic effect in these organs, such as necrosis, congestion, infiltrations, edema, splitting of muscle bundles and degenerations. This study shows that radiation from mobile phones contributes to histological changes in various visceral organs. Blood parameters showed a significant increase in platelets, bleeding and clotting time compared to the control group. The effect of EMR (Electromagnetic Radiation) on histology related to free radicals, increased lipid peroxidation in the cell membrane, and change in electrolyte concentration. An increase in platelets, bleeding and clotting time can also affect the rise in body temperature, ions and stimulations of stem cell divisions. Keywords: electromagnetic radiations, mice, physiology, histology, mobile phone.

Peculiarities of Agonistic and Marking Behavior in Male Laboratory Mice (Mus musculuc) of Different Inbred Strains during the Formation of Social Hierarchy

Peculiarities of Agonistic and Marking Behavior in Male Laboratory Mice (Mus musculuc) of Different Inbred Strains during the Formation of Social Hierarchy

The effect of Alloxan induced diabetes on baseline comet test in male laboratory mice fed on different feeding systems

Background: The comet analysis (electromagnetic relay analysis of a single cell) is ahighly sensitive method for determining DNA damage because to exposure tocarcinogens and other substances that consequently affect fertility.Objective: the aim of this study is to Evaluation the broken DNA in male diabeticmice. Created by alloxan and knowledge of the effect of some nutritional systems onthe treatment and repair of genetic material due to diabetes.Materials and methods: In this study were used, 42 male Albino mice labs at the ageof 2-3 months and weight (25-30) g then 6 animals were isolated to represent thecontrol group, The remaining animals were injected between the thighs by alloxan 150mg / kg and left the next day to make sure hit by diabetes and randomly distributed tosix groups in addition to a set of Not affected control transactions.Results and conclusion: It was found from the results of the statistical analysis shownin figure(1) showed the presence of the highest percentage of injuries in the geneticmaterial that was in the group of animals with diabetes and untreated for the durationof the experiment, as it was clear from the photos of this group that the tail lengthresulting from the migration of the genetic material DNA to outside the nucleusbecause to its damage, as well as the results showed that the group of animals affectedby diabetes and the treatment by adding the Salvia officinalis plant to both plant andanimal nutrition had a significant decrease (<0.05> P) in the proportion of geneticmaterial injuries where the proportion of high (long guilt) infections was low in thesetwo The two groups compared to the group of animals with diabetes and untreated forthe duration of the experiment.

Assessing the effect of compounds from plantar foot sweat, nesting material, and urine on social behavior in male mice, Mus musculus.

Home cage aggression causes poor welfare in male laboratory mice and reduces data quality. One of the few proven strategies to reduce aggression involves preserving used nesting material at cage change. Volatile organic compounds from the nesting material and several body fluids not only correlate with less home cage aggression, but with more affiliative allo-grooming behavior. To date, these compounds have not been tested for a direct influence on male mouse social behavior. This study aimed to determine if 4 previously identified volatile compounds impact home cage interactions. A factorial design was used with cages equally split between C57BL/6N and SJL male mice (N = 40). Treatments were randomly assigned across cages and administered by spraying one compound solution on each cage's nesting material. Treatments were refreshed after day 3 and during cage change on day 7. Home cage social behavior was observed throughout the study week and immediately after cage change. Several hours after cage change, feces were collected from individual mice to measure corticosterone metabolites as an index of social stress. Wound severity was also assessed after euthanasia. Measures were analyzed with mixed models. Compound treatments did not impact most study measures. For behavior, SJL mice performed more aggression and submission, and C57BL/6N mice performed more allo-grooming. Wound severity was highest in the posterior region of both strains, and the middle back region of C57BL/6N mice. Posterior wounding also increased with more observed aggression. Corticosterone metabolites were higher in C57BL/6N mice and in mice treated with 3,4-dimethyl-1,2-cyclopentanedione with more wounding. These data confirm previous strain patterns in social behavior and further validates wound assessment as a measure of escalated aggression. The lack of observed treatment effects could be due to limitations in the compound administration procedure and/or the previous correlation study, which is further discussed.

Isometric skeletal muscle contractile properties in common strains of male laboratory mice.

Assessing contractile function of skeletal muscle in murine models is a commonly employed laboratory technique that investigators utilize to measure the impact of genetic manipulations, drug efficacy, or other therapeutic interventions. Often overlooked is the potential for the strain of the mouse to influence the functional properties of the skeletal muscle. Thus, we sought to characterize commonly assessed isometric force measures in the hindlimb muscles across a variety of mouse strains. Using 6-8-week-old male mice, we measured isometric force, fatigue susceptibility, relaxation kinetics, muscle mass, myofiber cross-sectional area, and fiber type composition of the extensor digitorum longus (EDL) and soleus muscles in C57BL/6NJ, BALB/cJ, FVB/NJ, C57BL/6J, and C57BL/10 mice. The data demonstrate both unique differences and a number of similarities between both muscles in the various genetic backgrounds of mice. Soleus muscle specific force (i.e., force per unit size) exhibited higher variation across strains while specific force of the EDL muscle exhibited minimal variation. In contrast, absolute force differed only in a few mouse strains whereas analysis of muscle morphology revealed many distinctions when compared across all the groups. Collectively, the data suggest that the strain of the mouse can potentially influence the measured biological outcome and may possibly promote a synergistic effect with any genetic manipulation or therapeutic intervention. Thus, it is critical for the investigator to carefully consider the genetic background of the mouse used in the experimental design and precisely document the strain of mouse employed during publication.

Prolactin Action Is Necessary for Parental Behavior in Male Mice.

Parental care is critical for successful reproduction in mammals. Recent work has implicated the hormone prolactin in regulating male parental behavior, similar to its established role in females. Male laboratory mice show a mating-induced suppression of infanticide (normally observed in virgins) and onset of paternal behavior 2 weeks after mating. Using this model, we sought to investigate how prolactin acts in the forebrain to regulate paternal behavior. First, using c-fos immunoreactivity in prolactin receptor (Prlr) Prlr-IRES-Cre-tdtomato reporter mouse sires, we show that the circuitry activated during paternal interactions contains prolactin-responsive neurons in multiple sites, including the medial preoptic nucleus, bed nucleus of the stria terminalis, and medial amygdala. Next, we deleted Prlr from three prominent cell types found in these regions: glutamatergic, GABAergic, and CaMKIIα. Prlr deletion from CaMKIIα, but not glutamatergic or GABAergic cells, had a profound effect on paternal behavior as none of these KO males completed the pup-retrieval task. Prolactin was increased during mating, but not in response to pups, suggesting that the mating-induced secretion of prolactin is important for establishing the switch from infanticidal to paternal behavior. Pharmacological blockade of prolactin secretion at mating, however, had no effect on paternal behavior. In contrast, suppressing prolactin secretion at the time of pup exposure resulted in failure to retrieve pups, with exogenous prolactin administration rescuing this behavior. Together, our data show that paternal behavior in sires is dependent on basal levels of circulating prolactin acting at the time of interaction with pups, mediated through Prlr on CaMKIIα-expressing neurons.SIGNIFICANCE STATEMENT Parental care is critical for offspring survival. Compared with maternal care, however, the neurobiology of paternal care is less well understood. Here we show that the hormone prolactin, which is most well known for its female-specific role in lactation, has a role in the male brain to promote paternal behavior. In the absence of prolactin signaling specifically during interactions with pups, father mice fail to show normal retrieval behavior of pups. These data demonstrate that prolactin has a similar action in both males and females to promote parental care.

Protein profiles from used nesting material, saliva, and urine correspond with social behavior in group housed male mice, Mus musculus

Current understanding of how odors impact intra-sex social behavior is based on those that increase intermale aggression. Yet, odors are often promoted to reduce fighting among male laboratory mice. It has been shown that a cage of male mice contains many proteins used for identification purposes. However, it is unknown if these proteins relate to social behavior or if they are uniformly produced across strains. This study aimed to compare proteomes from used nesting material and three sources (sweat, saliva, and urine) from three strains and compare levels of known protein odors with rates of social behavior. Used nesting material samples from each cage were analyzed using LC-MS/MS. Sweat, saliva, and urine samples from each cage's dominant and subordinate mouse were also analyzed. Proteomes were assessed using principal component analyses and compared to behavior by calculating correlation coefficients between PC scores and behavior proportions. Twenty-one proteins from nesting material either correlated with affiliative behavior or negatively correlated with aggression. Notably, proteins from the major urinary protein family, odorant binding protein family, and secretoglobin family displayed at least one of these patterns, making them candidates for future work. These findings provide preliminary information about how proteins can influence male mouse behavior. SignificanceResearch on how olfactory signals influence same sex social behavior is primarily limited to those that promote intermale aggression. However, exploring how olfaction modulates a more diverse behavioral repertoire will improve our foundational understanding of this sensory modality. In this proteome analysis we identified a short list of protein signals that correspond to lower rates of aggression and higher rates of socio-positive behavior. While this study is only correlational, it sets a foundation for future work that can identify protein signals that directly influence social behavior and potentially identify new murine pheromones.

Effect of 3d-metal gluconates on leukocyte parameters of endogenous intoxication

Background. The development of endogenous intoxication in the treatment of oncological pathology with cytostatic drugs complicates targeted therapy, so the search for correctors of these conditions is an actual task. Previously, we have shown in vivo the corrective effect of 3d-metal gluconates on the humoral link of immunity with the administration of the widely used cytostatic cyclophosphamide. It is of interest to evaluate the effect of 3d-metal gluconates on changes in leukocyte parameters of endogenous intoxication affected by cyclophosphamide.
 Aim. Evaluation of the effect of 3d-metal gluconates (Mn, Fe, Co, Cu, Zn) on the degree of endogenous intoxication in mice against the background of the cytostatic effect of cyclophosphamide.
 Material and methods. The experiment was carried out on white laboratory male mice weighing 2528 g, divided into 9 groups [1 intact animals, 2 administration of cyclophosphamide without treatment, 3 administration of cyclophosphamide and a comparison drug with an immunostimulating effect, 4 administration of cyclophosphamide and the comparison drug calcium gluconate, groups 59 administration of cyclophosphamide and gluconates of 3d-metals (MnGl, FeGl, CoGl , CuGl and ZnGl, respectively)], 12 individuals each, kept in the vivarium conditions on a standard diet. Endogenous intoxication was induced by a single injection of cyclophosphamide. 3d-metal gluconates (Mn, Fe, Co, Cu, Zn) and comparison drugs (glucosaminylmuramyl dipeptide in the form of Likopid, and calcium gluconate) were used to correct changes in the immune system. The administration of the drugs was started 24 hours after the administration of the cytostatic and then daily orally during 21 days. Blood sampling was performed on the 22nd day. The assessment of the degree of endogenous intoxication was carried out by determining the leukocyte indices: stress activity index, leukocyte intoxication index, nuclear index of the degree of endotoxicosis, and leukocyte shift index. Statistical processing of the results was performed using the Statistica 10.0 program. To calculate the significance of differences between groups, the nonparametric MannWhitney test was used. Changes were considered significant at p 0.05.
 Results. After the administration of cyclophosphamide in animals, a significant change in the leukocyte formula, which indicates an acute intoxication of the body, was observed: there was a decrease in the content of monocytes (3 times), segmented neutrophils (1.5 times), an increase in stab neutrophils (2 times), lymphocytes (1.1 times). The intake of 3d-metal gluconates led to the correction of leukocyte indices, the degree of which statistically significantly exceeded the degree of correction by the comparison drugs Licopid and Calcium gluconate (p 0.05), and for Zn (II) gluconate it was from 45 to 84%, for Mn (II) gluconate from 44 to 100%.
 Conclusion. Gluconates of 3d-metals reduce the degree of endogenous intoxication caused by cyclophosphamide, increase the reactivity of phagocytes and the regeneration rate of the leukocyte link. In terms of efficiency, 3d-metal gluconates can be arranged in the following order (according to metals): Mn ˃Zn ˃Cu ˃Co ˃Fe.