Increased Lactobacillus Abundance Contributes to Stress Resilience in Mice Exposed to Chronic Social Defeat Stress.

INTRODUCTION: Accumulating evidence indicates that abnormalities in the composition of gastrointestinal (GI) microbiota play a vital role in stress-related disorders. Both human beings and animals perceive stressful events differently, i.e., resilience or susceptibility. However, the role of GI microbiota in stress resilience/susceptibility and the underlying mechanisms remain largely unknown. METHODS AND RESULTS: Sixty male C57BL/6J mice were exposed to 10-day chronic social defeat stress (CSDS), and 28 were found to be resilient to CSDS. We next analyzed microbiota compositions in the cecum using 16S rDNA gene sequencing, which revealed a significant increase in the relative abundance of Lactobacillus at the genus level in the resilient mice. In subsequent experiments, we found that oral administration of a strain of Lactobacillus (Lactobacillus murinus) for 2 weeks attenuated the increased levels of stress-induced corticosterone and anxiety-like behavior in stress-susceptible mice. The mRNA expression of tryptophan hydroxylase 2 (a rate-limiting enzyme in serotonin [5-HT] synthesis) was also significantly increased in the dorsal raphe nucleus (DR) of stress-susceptible mice. CONCLUSIONS: Lactobacillus contributes to stress resilience, and the DR 5-HT system may play an important role during this process. The above results suggest that certain organisms in the GI tract may play an essential role in stress response and be useful in the prevention and treatment of some stress-related psychiatric disorders, such as depression.

Chronic Co-species Housing Mice and Rats Increased the Competitiveness of Male Mice.

Rats are predators of mice in nature. Nevertheless, it is a common practice to house mice and rats in a same room in some laboratories. In this study, we investigated the behavioral and physiological responsively of mice in long-term co-species housing conditions. Twenty-four male mice were randomly assigned to their original raising room (control) or a rat room (co-species-housed) for more than 6 weeks. In the open-field and light-dark box tests, the behaviors of the co-species-housed mice and controls were not different. In a 2-choice test of paired urine odors [rabbit urine (as a novel odor) vs. rat urine, cat urine (as a natural predator-scent) vs. rabbit urine, and cat urine vs. rat urine], the co-species-housed mice were more ready to investigate the rat urine odor compared with the controls and may have adapted to it. In an encounter test, the rat-room-exposed mice exhibited increased aggression levels, and their urines were more attractive to females. Correspondingly, the levels of major urinary proteins were increased in the co-species-housed mouse urine, along with some volatile pheromones. The serum testosterone levels were also enhanced in the co-species-housed mice, whereas the corticosterone levels were not different. The norepinephrine, dopamine, and 5-HT levels in the right hippocampus and striatum were not different between the 2. Our findings indicate that chronic co-species housing results in adaptation in male mice; furthermore, it appears that long-term rat-odor stimuli enhance the competitiveness of mice, which suggests that appropriate predator-odor stimuli may be important to the fitness of prey animals.

A Study of 2,3,7,8-Tetrachlorodibenzo-p-dioxin Induced Liver Injury in Jian Carp (Cyprinus carpio var. Jian) Using Precision-Cut Liver Slices.

The aim of this study was to establish a model for the study of liver injury induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in Jian carp using precision-cut liver slices (PCLS). PCLS were treated with TCDD at concentrations of 0, 0.05, 0.1, 0.3, and 0.6 µg/L for 6 h, followed by collection of the culture supernatant and PCLS for analysis. Several biochemical indices were analyzed, including glutamic pyruvic transaminase (GPT), glutamic oxaloacetic transaminase (GOT), lactate dehydrogenase (LDH), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA). Expression of mRNA was also estimated for cytochrome P4501A (CYP1A), aryl hydrocarbon receptor2 (AhR2), and aryl hydrocarbon receptor nuclear translocator2 (ARNT2). Results showed that some significant effects (p < 0.05) in MDA, GSH-Px and PCLS viability were observed at a TCDD concentration as low as 0.05 µg/L, and the observed effects increased with exposure concentration. Following exposure to TCDD for 6 h at a concentration of 0.3 µg/L, significant increases (p < 0.01) in the content of GPT, GOT, MDA, and LDH were observed, while SOD activity, GSH-Px activity, and PCLS viability were decreased (p < 0.01 or p < 0.05). Exposure to 0.3 µg/L TCDD also resulted in increased expression of mRNA for CYP1A, AhR2, and ARNT2. Overall, these results provide evidence of TCDD-induced liver injury and oxidative stress in Jian carp. These results also support the use of PCLS as an in vitro model for the evaluation of hepatotoxicity in Jian carp.

Next generation digital PCR measurement of hepatitis B virus copy number in formalin-fixed paraffin-embedded hepatocellular carcinoma tissue.

BACKGROUND: Hepatocellular carcinoma (HCC) is strongly associated with hepatitis B virus (HBV) infection. False-negative results are common in routine serological tests and quantitative real-time PCR because of HBV surface antigen (HBsAg) variation and low HBV copy number. Droplet digital PCR (ddPCR), a next generation digital PCR, is a novel, sensitive, and specific platform that can be used to improve HBV detection. METHODS: A total of 131 HCC cases with different tumor stages and clinical features were initially classified with a serological test as HBsAg positive (n = 107) or negative (n = 24) for HBV infection. Next, DNA templates were prepared from the corresponding formalin-fixed paraffin-embedded (FFPE) tissues to determine HBV copy number by ddPCR. RESULTS: HBV copy numbers, successfully determined for all clinical FFPE tissues (n = 131), ranged from 1.1 to 175.5 copies/µL according to ddPCR. The copy numbers of HBV were positively correlated with tumor-nodes-metastasis (P = 0.008) and Barcelona-Clinic Liver Cancer (P = 0.045) classification. Moreover, serum cholinesterase correlated with hepatitis B viral load (P = 0.006). CONCLUSIONS: HBV infection is a key factor that influences tumorigenesis in HCC by regulating tumor occurrence and development. ddPCR improves the analytical sensitivity and specificity of measurements in nucleic acids at a single-molecule level and is suitable for HBV detection.

5-HT1A receptors within the intermediate lateral septum modulate stress vulnerability in male mice.

Chronic stress is a major risk factor for psychiatric disorders. However, certain individuals may be at higher risk due to greater stress susceptibility. Elucidating the neurobiology of stress resilience and susceptibility may facilitate the development of novel strategies to prevent and treat stress-related disorders such as depression. Mounting evidence suggests that the serotonin (5-HT) system is a major regulator of stress sensitivity. In this study, we assessed the functions of 5-HT1A and 5-HT2A receptors within the lateral septum (LS) in regulating stress vulnerability. Among a group of male mice exposed to chronic social defeat stress (CSDS), 47.2% were classified as stress-susceptible, and these mice employed more passive coping strategies during the defeat and exhibited more severe anxiety- and depression-like behaviors during the following behavioral tests. These stress-susceptible mice also exhibited elevated neuronal activity in the LS as evidenced by greater c-Fos expression, greater activity of 5-HT neurons in both the dorsal and median raphe nucleus, and downregulated expression of the 5-HT1A receptor in the intermediate LS (LSi). Finally, we found the stress-induced social withdrawal symptoms could be rapidly relieved by LSi administration of 8-OH-DPAT, a 5-HT1A receptor agonist. These results indicate that 5-HT1A receptors within the LSi play an important role in stress vulnerability in mice. Therefore, modulation of stress vulnerable via 5-HT1A receptor activation in the LSi is a potential strategy to treat stress-related psychiatric disorders.

GABAergic synapses from the ventral lateral septum to the paraventricular nucleus of hypothalamus modulate anxiety.

Emotional disorders, such as anxiety and depression, represent a major societal problem; however, the underlying neurological mechanism remains unknown. The ventral lateral septum (LSv) is implicated in regulating processes related to mood and motivation. In this study, we found that LSv GABAergic neurons were significantly activated in mice experiencing chronic social defeat stress (CSDS) after exposure to a social stressor. We then controlled LSv GABAergic neuron activity using a chemogenetic approach. The results showed that although manipulation of LSv GABAergic neurons had little effect on anxiety-like behavioral performances, the activation of LSv GABAergic neurons during CSDS worsened social anxiety during a social interaction (SI) test. Moreover, LSv GABAergic neurons showed strong projections to the paraventricular nucleus (PVN) of the hypothalamus, which is a central hub for stress reactions. Remarkably, while activation of GABAergic LSv-PVN projections induced social anxiety under basal conditions, activation of this pathway during CSDS alleviated social anxiety during the SI test. On the other hand, the chemogenetic manipulation of LSv GABAergic neurons or LSvGABA-PVN projections had no significant effect on despair-like behavioral performance in the tail suspension test. Overall, LS GABAergic neurons, particularly the LSv GABAergic-PVN circuit, has a regulatory role in pathological anxiety and is thus a potential therapeutic target for the treatment of emotional disorders.

Dopamine D2 receptor within the intermediate region of the lateral septum modulate social hierarchy in male mice.

The dopamine (DA) system has long been involved in social hierarchies; however, the specific mechanisms have not been elucidated. The lateral septum (LS) is a limbic brain structure that regulates various emotional, motivational, and social behaviors. DA receptors are abundantly expressed in the LS, modulating its functions. In this study, we evaluated the functions of DA receptors within different subregions of the LS in social dominance using a confrontation tube test in male mice. The results showed that mice living in social groups formed linear dominance hierarchies after a few days of cohousing, and the subordinates showed increased anxiety. Fos expressions was elevated in the entire LS after a confrontation tube test in the subordinates. However, DA neurons were more activated in the dominates within the ventral tegmental area and the dorsal raphe nucleus. Quantitative real-time polymerase chain reaction results showed that D2 receptor (D2R) within the intermediate region of the LS (LSi) were elevated in the subordinate. In the following pharmacological studies, we found simultaneous D2R activation in the dominants and D2R inhibition in the subordinates switched the original dominant-subordinate relationship. The aforementioned results suggested that D2R within the LSi plays an important role in social dominance in male mice. These findings improve our understanding of the neural mechanisms underlying the social hierarchy, which is closely related to our social life and happiness.

5-HT1A receptor in the central amygdala and 5-HT2A receptor in the basolateral amygdala are involved in social hierarchy in male mice.

Most social animals self-organize into dominance hierarchies that strongly influence their behavior and health. The serotonin (5-HT) system is believed to play an important role in the formation of social hierarchy. 5-HT receptors are abundantly expressed in the amygdala, which is considered as the central node for the perception and learning of social hierarchy. In this study, we assessed the functions of various 5-HT receptor subtypes related to social rank determination in different subregions of the amygdala using the confrontation tube test in mice. We revealed that most adult C57BL/6 J male mice exhibited a linear social rank after a few days of cohousing. The tube test ranks were slightly related to anxiety-like behavioral performance. After the tube test, the amygdala and 5-HT neurons in the dorsal raphe nucleus were activated in lower-rank individuals. Quantitative real-time polymerase chain reaction analysis revealed that despite the high expression of 5-HT1A receptor mRNA in the central amygdala (CeA), 5-HT2A receptor mRNA expression was downregulated in the basolateral amygdala (BLA) in higher-rank individuals. The dominant-subordinate relationship between mouse pairs could be switched via pharmacological modulation of these receptors in CeA and BLA, suggesting that these expression changes are essential for establishing social ranks. Our findings provide novel insights into the divergent functions of 5-HT receptors in the amygdala related to social hierarchy, which is closely related to our health and welfare.

Dopamine D2 receptors in the dorsomedial prefrontal cortex modulate social hierarchy in male mice.

Social hierarchy greatly influences behavior and health. Both human and animal studies have signaled the medial prefrontal cortex (mPFC) as specifically related to social hierarchy. Dopamine D1 receptors (D1Rs) and D2 receptors (D2Rs) are abundantly expressed in the mPFC, modulating its functions. However, it is unclear how DR-expressing neurons in the mPFC regulate social hierarchy. Here, using a confrontation tube test, we found that most adult C57BL/6J male mice could establish a linear social rank after 1 week of cohabitation. Lower rank individuals showed social anxiety together with decreased serum testosterone levels. D2R expression was significantly downregulated in the dorsal part of mPFC (dmPFC) in lower rank individuals, whereas D1R expression showed no significant difference among the rank groups in the whole mPFC. Virus knockdown of D2Rs in the dmPFC led to mice being particularly prone to lose the contests in the confrontation tube test. Finally, simultaneous D2R activation in the subordinates and D2R inhibition in the dominants in a pair switched their dominant-subordinate relationship. The above results indicate that D2Rs in the dmPFC play an important role in social dominance. Our findings provide novel insights into the divergent functions of prefrontal D1Rs and D2Rs in social dominance, which may contribute to ameliorating social dysfunctions along with abnormal social hierarchy.

mGlu2/3 receptors within the ventral part of the lateral septal nuclei modulate stress resilience and vulnerability in mice.

Resilience refers to the ability to withstand or recover quickly from difficult conditions. Identification of the neurobiological mechanisms underlying resilience offers a novel way to the prevention and treatment of stress-induced psychiatric disorders such as depression. The septal nuclei have been described as an important node in emotional regulations. Metabotropic glutamate receptors (mGluRs) are abundantly expressed within the septum and play important regulatory roles in its neural activity. In this study, we assessed the functional roles of the mGlu2/3Rs and mGlu5Rs within different subregions of the septum in modulating stress resilience and vulnerability by using chronic social defeat stress (CSDS) paradigms in C57BL/6J male mice. Our results showed that approximately 47.9% of subjects exhibited anxiety- or depression-like behaviors after exposure to CSDS. The susceptible mice showed higher c-Fos expression in the lateral septal nucleus after confronted with an attacker. Compared with the resilient and control groups, the expression of mGlu2/3Rs was significantly down-regulated in the ventral part of lateral septal nucleus (LSv), but the expression of mGlu5Rs showed no significant difference among the three groups in the whole septum. Finally, we found the stress-induced social withdrawal symptoms could be rapidly relieved by intra-LSv injection of LY379268, an mGlu2/3Rs' agonist. Our findings point to an important role for mGlu2/3Rs in the LSv in promoting stress resilience and may provide potential new therapeutic targets for stress-induced psychiatric disorders, such as anxiety and depression.

GABA(B) receptors within the lateral habenula modulate stress resilience and vulnerability in mice.

Resilience means "the ability to withstand or recover quickly in the face of adversity". Elucidating the neural and molecular mechanisms underlying stress resilience will facilitate the development of more effective treatments for stress-induced psychiatric disorders such as depression. The habenular nuclei, which consist of the medial and lateral sub-regions (MHb and LHb, respectively), have been described as a critical node in emotional regulations. GABA(B) receptors play an important regulatory role in habenular activity. In this study, we assessed the functional role of GABA(B) receptors within the habenula in stress resilience and vulnerability by using chronic social defeat stress (CSDS) model in C57BL/6 male mice. Approximately 47.1% of mice exhibited depression- or anxiety-like behaviors after exposure to CSDS. The vulnerable mice presented elevated c-Fos expression in the LHb when confronted with an attacker. On the other hand, the expression of GABA(B) receptors, including both GABA(B1) and GABA(B2) subunits, was significantly down-regulated in the LHb of the susceptible mice. Finally, we found the stress-induced social withdrawal symptoms could be rapidly relieved by intra-LHb injection of both baclofen and CGP36216 (a GABA(B) receptor agonist and antagonist respectively). The above results indicated that GABA(B) receptors in the LHb may play an important role in stress resilience and vulnerability, and thus, may be an important therapeutic target for treatments of stress-induced psychiatric disorders.

mGlu2/3 receptor in the prelimbic cortex is implicated in stress resilience and vulnerability in mice.

Resilience, referring to "achieving a positive outcome in the face of adversity", is a common phenomenon in daily life. Elucidating the mechanisms of stress resilience is instrumental to developing more effective treatments for stress-related psychiatric disorders such as depression. Metabotropic glutamate receptors (mGlu2/3 and mGlu5) within the medial prefrontal cortex (mPFC) have been recently recognized as promising therapeutic targets for rapid-acting antidepressant treatment. In this study, we assessed the functional roles of the mGlu2/3 and mGlu5 within different subregions of the mPFC in modulating stress resilience and vulnerability by using chronic social defeat stress (CSDS) paradigms in mice. Our results showed that approximately 51.6% of the subjects exhibited depression- or anxiety-like behaviors after exposure to CSDS. When a susceptible mouse was confronted with an attacker, c-Fos expression in the prelimbic cortex (PrL) subregion of the mPFC substantially increased. Compared with the resilient and control groups, the expression of mGlu2/3 was elevated in the PrL of the susceptible group. The expression of mGlu5 showed no significant difference among the three groups in the whole mPFC. Finally, we found that the social avoidance symptoms of the susceptible mice were rapidly relieved by intra-PrL administration of LY341495-an mGluR2/3 antagonists. The above results indicate that mGluR2/3 within the PrL may play an important regulatory role in stress-related psychiatric disorders. Our results are meaningful, as they expand our understanding of stress resilience and vulnerability which may open an avenue to develop novel, personalized approaches to mitigate depression and promote stress resilience.

The GABA(B1) receptor within the infralimbic cortex is implicated in stress resilience and vulnerability in mice.

Resilience is the capacity to maintain normal psychological and physical functions in the face of stress and adversity. Understanding how one can develop and enhance resilience is of great relevance to not only promoting coping mechanisms but also mitigating maladaptive stress responses in psychiatric illnesses such as depression. Preclinical studies suggest that GABA(B) receptors (GABA(B1) and GABA(B2)) are potential targets for the treatment of major depression. In this study, we assessed the functional role of GABA(B) receptors in stress resilience and vulnerability by using a chronic unpredictable stress (CUS) model in mice. As the medial prefrontal cortex (mPFC) plays a key role in the top-down modulation of stress responses, we focused our study on this brain structure. Our results showed that only approximately 41.9% of subjects exhibited anxiety- or despair-like behaviors after exposure to CUS. The vulnerable mice showed higher c-Fos expression in the infralimbic cortex (IL) subregion of the mPFC when exposed to a social stressor. Moreover, the expression of GABA(B1) but not GABA(B2) receptors was significantly downregulated in IL subregion of susceptible mice. Finally, we found that intra-IL administration of baclofen, a GABA(B) receptor agonist, rapidly relieved the social avoidance symptoms of the "stress-susceptible" mice. Taken together, our results show that the GABA(B1) receptor within the IL may play an important role in stress resilience and vulnerability, and thus open an avenue to develop novel, personalized approaches to promote stress resilience and treat stress-related psychiatric disorders.

Efficacy of arbidol on lethal hantaan virus infections in suckling mice and in vitro.

AIM: Arbidol is an immunomodulator that was first developed in Russia. In this study, we report the antiviral activity of arbidol against Hantaan virus (HTNV) in vitro and in vivo. METHODS: The antiviral activity of arbidol in vitro was determined by plaque-forming assay, ranging from 0.5 to 8 microg/mL. To investigate whether arbidol has an antiviral effect in vivo, suckling BALB/c mice infected with HTNV were treated with arbidol at 24 h before infection with a 5, 10 or 20 mg.kg(-1).d(-1), once per day, for 10 days. On day 12 and 28 post infection (pi), histopathological changes and viral antigen were detected. On days 4, 8, 12, and 16 pi, the viral load of target organs and serum TNF-alpha levels of arbidol-treated animals were determined. RESULTS: Arbidol was found to have potent inhibitory activity against HTNV when added in vitro before or after viral infection, with a 50% inhibitory concentration (IC(50)) of 0.9 and 1.2 microg/mL, respectively. The 50% lethal dose (LD(50)) of arbidol for suckling mice was 78.42 mg.kg(-1).d(-1). Oral administration of arbidol increased both survival rate and mean time to death (MTD). Treatment with arbidol reduced histopathological changes, decreased viral load and viral antigen levels, and modulated the level of serum TNF-alpha. CONCLUSION: Arbidol has the ability to elicit protective antiviral activity against HTNV in vivo and in vitro.Acta Pharmacologica Sinica (2009) 30: 1015-1024; doi: 10.1038/aps.2009.53; published online 8 June 2009.

Dual role of preputial gland secretion and its major components in sex recognition of mice.

This study was aimed at validating the sexual attractiveness of hexadecanol and hexadecyl acetate, two putative pheromone compounds, from preputial gland secretion of mice. These two compounds have been reported to be among the major components of preputial gland secretion in both sexes but higher in quantity in males than females. In this study, we show that castration suppressed the production of the two compounds, further suggesting their association with maleness. Adding preputial gland secretion and the synthetic analogs of the two compounds to castrated male urine at their physiological levels in intact males increased the attractiveness of castrated male urine to female mice, showing that the two compounds were indeed male pheromones. Furthermore, their sexual attractiveness disappeared upon removing the vomeronasal organs (VNOs) from female recipients. Replenishing castrated male urine with preputial gland secretion and the two compounds at their physiological levels in females increased the attractiveness of castrated male urine to males. Such a reversal of sexual attractiveness for hexadecanol and hexadecyl acetate suggests that they had opposing dual effects in sexual attractiveness in a dosage-dependent manner.

Author Correction: Quantitative inheritance of volatile pheromones and darcin and their interaction in olfactory preferences of female mice.

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Quantitative inheritance of volatile pheromones and darcin and their interaction in olfactory preferences of female mice.

In this study, we examined how urine-borne volatile compounds (UVCs) and darcin of male mice are inherited from parents and interact to modulate the olfactory preferences of females using two inbred strains of mice, C57Bl/6 (C57) and BALB/c (BALB), and their reciprocal hybrids (BC = BALBâ™€× C57♂; CB = C57♀ × BALB♂). Chemical analysis revealed that the UVCs of C57BL/6 males were quantitatively distinguishable from those of BALB/c males. Darcin was detected in C57 urine, but not in BALB urine. The levels of UVCs and darcin in both BC and CB were intermediate between those of C57 and BALB. Behaviourally, C57 females consistently preferred BALB male urine over C57 or CB males despite that there are trace amounts of darcin in BALB urine. However, the preference for BALB urine disappeared in contact two-choice tests of BALB vs. BC pairs, and restored when recombinant darcin was added to BALB male urine. Our results suggested that both UVCs and darcin in male mice are quantitatively inherited and interact to affect the olfactory preferences of females.

Human bocavirus induces apoptosis and autophagy in human bronchial epithelial cells.

Human bocavirus (HBoV) is classified in the Bocavirus genus within the Parvoviridae family, first identified from children with respiratory diseases. Previous studies have investigated the stimulating effect of HBoV on cell apoptosis and autophagy. In the present study, human bronchial epithelial cells (HBECs) were utilized to examine the mechanism of HBoV recombination expressing vector (pWHL-1) on the promotion of cell apoptosis and autophagy. The results from the present study indicated that pWHL-1 inhibited the proliferation of HBECs in a time-dependent manner. Additionally, pWHL-1induced apoptosis, as substantiated by an increased apoptotic rate and presence of autophagosomes. Following pWHL-1 transfection, proliferating cell nuclear antigen, caspase-3 and B cell lymphoma 2 (Bcl-2) protein expression levels were decreased, with the exception of Bcl-2 associated × (Bax) protein, which increased. mRNA and protein expression levels of microtubule-associated protein 1A/1B-light chain 3 (LC3) II and autophagy protein 5 were increased in pWHL-1-transfected HBECs, whereas, the mRNA and protein levels of LC3I and sequestosome 1 were decreased. Notably, pWHL-1 also enhanced the activation of p53 and inhibited AKT activation in HBECs. Results from the present study suggest that pWHL-1 induces apoptosis and autophagy, thus providing a novel insight into the effect of HBoV and its uses in respiratory diseases.

Protective action of the phyllanthin against carbon tetrachloride-induced hepatocyte damage in Cyprinus carpio.

The present study was to investigate the protective effect and possible mechanism of phyllanthin against carbon tetrachloride (CCl4)-induced hepatocyte damage in carp. Phyllanthin (5, 10, and 15 µg/ml) was added to carp primary hepatocytes before (pre-treatment) and after (post-treatment) incubation of the hepatocytes in medium containing CCl4 at 8 mM; supernatant and cell were collected for the analyses of cell viability, biochemical parameters, and gene expression. The results showed that phyllanthin at the concentration of 15 µg/ml significantly suppressed the elevation of glutamate pyruvate transaminase (GPT), glutamate oxalate transaminase (GOT), lactate dehydrogenase (LDH), and malondialdehyde (MDA), and the reduction of cell viability, superoxide dismutase (SOD) activity, cytochrome P450 1a (CYP1A), and cytochrome P450 3a (CYP3A) messenger RNA (mRNA) levels expect LDH in the post-treatment. The levels of GPT, GOT, and CYP1A mRNA were also effectively restored in the pretreatment with phyllanthin (10 µg/ml). Overall, our results suggested that phyllanthin may be used as a hepatoprotective agent to prevent liver diseases in fish.

Cross-Fostering of Male Mice Subtly Affects Female Olfactory Preferences.

The maternal environment has been shown to influence female olfactory preferences through early chemosensory experience. However, little is known about the influence of the maternal environment on chemosignals. In this study, we used two inbred mouse strains, C57BL/6 (C57) and BALB/c (BALB), and explored whether adoption could alter male chemosignals and thus influence female olfactory preferences. In Experiment 1, C57 pups were placed with BALB dams. Adult BALB females then served as the subjects in binary choice tests between paired male urine odours (BALB vs. C57, BALB vs. adopted C57 and C57 vs. adopted C57). In Experiment 2, BALB pups were placed with C57 dams, and C57 females served as the subjects in binary choice tests between paired male urine odours (C57 vs. BALB, C57 vs. adopted BALB, and BALB vs. adopted BALB). In both experiments, we found that females preferred the urine of males from different genetic backgrounds, suggesting that female olfactory preferences may be driven by genetic compatibility. Cross-fostering had subtle effects on female olfactory preferences. Although the females showed no preference between the urine odours of adopted and non-adopted males of the other strain, the BALB females preferred the urine odour of BALB males to that of adopted C57 males, whereas the C57 females showed no preference between the urine odour of C57 and adopted BALB males. Using gas chromatography-mass spectrometry (GC-MS) and stepwise discriminant analysis, we found that the ratios of volatile chemicals from urine and preputial gland secretions were altered in the fostered male mice; these changes may have resulted in the behavioural changes observed in the females. Overall, the results suggest that female mice prefer urine odours from males with different genetic backgrounds; this preference may be driven by genetic compatibility. The early maternal environment influences the chemosignals of males and thus may influence the olfactory preferences of females. Our study provides additional evidence in support of genotype-dependent maternal influences on phenotypic variability in adulthood.