Ginseng extracts improve circadian clock gene expression and reduce inflammation directly and indirectly through gut microbiota and PI3K signaling pathway.

Despite the potential benefits of herbal medicines for therapeutic application in preventing and treating various metabolic disorders, the mechanisms of action were understood incompletely. Ginseng (Panax ginseng), a commonly employed plant as a dietary supplement, has been reported to play its hot property in increasing body temperature and improving gut health. However, a comprehensive understanding of the mechanisms by which ginseng regulates body temperature and gut health is still incomplete. This paper illustrates that intermittent supplementation with ginseng extracts improved body temperature rhythm and suppressed inflammatory responses in peripheral metabolic organs of propylthiouracil (PTU)-induced hypothermic rats. These effects were associated with changes in gut hormone secretion and the microbiota profile. The in-vitro studies in ICE-6 cells indicate that ginseng extracts can not only act directly on the cell to regulate the genes related to circadian clock and inflammation, but also may function through the gut microbiota and their byproducts such as lipopolysaccharide. Furthermore, administration of PI3K inhibitor blocked ginseng or microbiota-induced gene expression related with circadian clock and inflammation in vitro. These findings demonstrate that the hot property of ginseng may be mediated by improving circadian clock and suppressing inflammation directly or indirectly through the gut microbiota and PI3K-AKT signaling pathways.

Fe-doped g-C3N4 with duel active sites for ultrafast degradation of organic pollutants via visible-light-driven photo-Fenton reaction: Insight into the performance, kinetics, and mechanism.

The photo-Fenton process provides a sustainable and cost-effective strategy for removing refractory organic contaminants in wastewater. Herein, a high-efficient Fe-doped g-C3N4 photocatalyst (Fe@CN10) with a unique 3D porous mesh structure was prepared by one-pot thermal polymerization for ultrafast degradation of azo dyes, antibiotics, and phenolic acids in heterogeneous photo-Fenton systems under visible light irradiation. Fe@CN10 exhibited a synergy between adsorption-degradation processes due to the co-existence of Fe3C and Fe3N active sites. Specifically, Fe3C acted as an adsorption site for pollutant and H2O2 molecules, while Fe3N acted as a photocatalytic active site for the high-efficient degradation of MO. Resultingly, Fe@CN10 showed a photocatalytic degradation rate of MO up to 140.32 mg/L min-1. The dominant ROS contributed to the removal of MO in the photo-Fenton pathway was hydroxyl radical (•OH). Surprisingly, as the key reactive species, singlet oxygen (1O2) generated from superoxide radical (•O2-) also efficiently attacked MO in a photo-self-Fenton pathway. Additionally, sponge/Fe@CN10 was prepared and filled in the continuous flow reactors for nearly 100% degradation of MO over 150 h when treating artificial organic wastewater. This work provided a facile route to prepare highly-active Fe-doped photocatalysts and develop a green photocatalytic system for wastewater treatment in the future.

Modified Sijunzi Granules Exhibit Hemostatic Effect by Activating Akt and Erk Signal Pathways via Regulating 5-HT and Its Receptors Levels.

OBJECTIVE: To investigate the hemostatic effect of modified Sijunzi Granules (MSG) in primary immune thrombocytopenia (ITP) zebrafish model and explore the potential mechanism. METHODS: AB strain wild type zebrafish were treated with simvastatin (6 µmol/L) for 24 h to establish the hemorrhage model (model control group). The zebrafish were treated with MSG at different doses (55.6, 167, and 500 µg/mL), respectively. The hemostatic effect was assessed by examining the intestinal bleeding and hemostatic rate. 5-Hydroxytryptamine (5-HT) content was determined using enzyme-linked immunosorbent assay (ELISA) assay. The expressions of 5-HT2aR, 5-HT2bR, and SERT genes were detected by quantitative real-time polymerase chain reaction(PCR). The protein expressions of protein kinase B (Akt), p-Akt, extracellular regulated protein kinases (Erk), and p-Erk were examined using Western blot analysis. RESULTS: The intestinal bleeding rate was 37%, 40%, and 80% in the 55.6, 167, and 500 µg/mL dose of MSG, respectively, in which 55.6 and 167 µg/mL MSG dose groups were associated with significantly decreased intestinal bleeding rate when compared with the model control group (70%, P<0.05). Significantly higher hemostatic rates were also observed in the 55.6 (54%) and 167 (52%) µg/mL MSG dose groups (P<0.05). MSG increased the 5-HT content and mRNA expression levels of 5-HT2aR, 5-HT2bR, and SERT (P<0.05). In addition, caspase3/7 activity was inhibited (P<0.05). Significant increase in p-Akt and p-Erk was also detected after treatment with MSG (P<0.05). CONCLUSIONS: MSG could reduce the incidence and severity of intestinal bleeding in zebrafish by activating MAPK/Erk and PI3K/Akt signal pathways through regulating the levels of 5-HT and its receptors, which may provide evidence for the treatment of ITP.

Phylogenetic signal in gut microbial community rather than in rodent metabolic traits.

Host phylogeny and environment have all been implicated in shaping the gut microbiota and host metabolic traits of mammals. However, few studies have evaluated phylogeny-associated microbial assembly and host metabolic plasticity concurrently, and their relationships on both short-term and evolutionary timescales. We report that the branching order of a gut microbial dendrogram was nearly congruent with phylogenetic relationships of seven rodent species, and this pattern of phylosymbiosis was intact after diverse laboratory manipulations. Laboratory rearing, diet or air temperature (Ta) acclimation induced alterations in gut microbial communities, but could not override host phylogeny in shaping microbial community assembly. A simulative heatwave reduced core microbiota diversity by 26% in these species, and led to an unmatched relationship between the microbiota and host metabolic phenotypes in desert species. Moreover, the similarity of metabolic traits across species at different Tas was not correlated with phylogenetic distance. These data demonstrated that the gut microbial assembly showed strong concordance with host phylogeny and may be shaped by environmental variables, whereas host metabolic traits did not seem to be linked with phylogeny.

Room temperature solid-state deformation induced high-density lithium grain boundaries to enhance the cycling stability of lithium metal batteries.

Due to its high theoretical capacity and low anode potential advantages, lithium is becoming the ideal high-capacity anode of next generation batteries. Nevertheless, the satisfactory long-term cyclability of lithium metal batteries is still not achieved. Inspired by the intrinsic soft nature of the lithium metal, we have developed a simple room temperature solid-state deformation route to overcome the lithium dendrite issue, and the cycle life of the deformation treated lithium anode is 5 times that of the untreated lithium anode. It is demonstrated that microscale lithium grains are divided into nanoscale lithium grains by directional friction forces of solid-state deformation. The lithium grain boundaries are lithiophilic active sites towards Li ions, which regulate homogeneous deposition of Li ions to form a thin and stable SEI film, eventually overcoming the lithium dendrite issue and enhancing the cyclability of lithium batteries. Overcoming the challenges in conventional tedious chemical routes to grow high-density grain boundary active sites for catalysis, the room temperature solid-state deformation route will pave a new road to grow high-density grain boundaries for fuel cells and metal-based batteries.

A systematic review and meta-analysis of thigmotactic behaviour in the open field test in rodent models associated with persistent pain.

Thigmotaxis is an innate predator avoidance behaviour of rodents. To gain insight into how injury and disease models, and analgesic drug treatments affect thigmotaxis, we performed a systematic review and meta-analysis of studies that assessed thigmotaxis in the open field test. Systematic searches were conducted of 3 databases in October 2020, March and August 2022. Study design characteristics and experimental data were extracted and analysed using a random-effects meta-analysis. We also assessed the correlation between thigmotaxis and stimulus-evoked limb withdrawal. This review included the meta-analysis of 165 studies We report thigmotaxis was increased in injury and disease models associated with persistent pain and this increase was attenuated by analgesic drug treatments in both rat and mouse experiments. Its usefulness, however, may be limited in certain injury and disease models because our analysis suggested that thigmotaxis may be associated with the locomotor function. We also conducted subgroup analyses and meta-regression, but our findings on sources of heterogeneity are inconclusive because analyses were limited by insufficient available data. It was difficult to assess internal validity because reporting of methodological quality measures was poor, therefore, the studies have an unclear risk of bias. The correlation between time in the centre (type of a thigmotactic metric) and types of stimulus-evoked limb withdrawal was inconsistent. Therefore, stimulus-evoked and ethologically relevant behavioural paradigms should be viewed as two separate entities as they are conceptually and methodologically different from each other.

Melatonin reduced colon inflammation but had no effect on energy metabolism in ageing Mongolian gerbils (Meriones unguiculatus).

In photoperiod-sensitive wild animals, the secretion of melatonin (MT) is modulated by external photoperiod, and MT affects inflammation and the ageing process. The beneficial effects of MT in delaying the progress of ageing have been reported in laboratory mice and rats. However, little is known about MT in wild mammals. In the current study, we investigated energy metabolism, microbial community structure and colon homeostasis in ageing Mongolian gerbils (Meriones unguiculatus) through exogenous supplementation of MT to test the hypothesis that MT has beneficial effects on gut homeostasis in ageing gerbils. Exogenous MT supplementation had no effect on energy metabolism in Mongolian gerbils but reduced the levels of circulating tumor necrosis factor-α (TNF-α), immune globulin G (IgG) and corticosterone (CORT). The increase in the level of inflammation in ageing animals was related to changes in the structure and diversity of the gut microbiota. At the genus level, the relative abundance of Prevotella, Treponema, Corynebacterium, and Sphingomonas was increased in ageing animals and decreased significantly by the treatment of MT. Christensenella and Lactobacillus were attenuated in ageing animals, and tended to be enhanced by MT treatment. Functions related to glycosphingolipid biosynthesis-ganglio series and lipopolysaccharide biosynthesis (metabolisms of cofactors, vitamins and glycan) were increased in ageing animals and decreased significantly by the treatment of MT. Our data suggest that a supplement of MT could improve colon homeostasis through changing the composition of gut microbiota and reducing inflammation in ageing gerbils.

Reductive Catalytic Difluorocarbene Transfer via Palladium Catalysis.

A palladium-catalyzed reductive difluorocarbene transfer reaction that tames difluorocarbene to couple with two electrophiles has been developed, representing a new mode of difluorocarbene transfer reaction. The approach uses low-cost and bulk industrial chemical chlorodifluoromethane (ClCF2 H) as the difluorocarbene precursor. It produces a variety of difluoromethylated (hetero)arenes from widely available aryl halides/triflates and proton sources, featuring high functional group tolerance and synthetic convenience without preparing organometallic reagents. Experimental mechanistic studies reveal that an unexpected Pd0/II catalytic cycle is involved in this reductive reaction, wherein the oxidative addition of palladium(0) difluorocarbene ([Pd0 (Ln )]=CF2 ) with aryl electrophile to generate the key intermediate aryldifluoromethylpalladium [ArCF2 Pd(Ln )X], followed by reaction with hydroquinone, is responsible for the reductive difluorocarbene transfer.

Genetic Diversity of a Heat Activated Channel-TRPV1 in Two Desert Gerbil Species with Different Heat Sensitivity.

Heat sensation and tolerance are crucial for determining species' survival and distribution range of small mammals. As a member of the transmembrane proteins, transient receptor potential vanniloid 1 (TRPV1) is involved in the sensation and thermoregulation of heat stimuli; however, the associations between animal's heat sensitivity and TRPV1 in wild rodents are less studied. Here, we found that Mongolian gerbils (Meriones unguiculatus), a rodent species living in Mongolia grassland, showed an attenuated sensitivity to heat compared with sympatrically distributed mid-day gerbils (M. meridianus) based on a temperature preference test. To explain this phenotypical difference, we measured the TRPV1 mRNA expression of two gerbil species in the hypothalamus, brown adipose tissue, and liver, and no statistical difference was detected between two species. However, according to the bioinformatics analysis of TRPV1 gene, we identified two single amino acid mutations on two TRPV1 orthologs in these two species. Further Swiss-model analyses of two TRPV1 protein sequences indicated the disparate conformations at amino acid mutation sites. Additionally, we confirmed the haplotype diversity of TRPV1 in both species by expressing TRPV1 genes ectopicly in Escherichia coli system. Taken together, our findings supplemented genetic cues to the association between the discrepancy of heat sensitivity and the functional differentiation of TRPV1 using two wild congener gerbils, promoting the comprehension of the evolutionary mechanisms of the TRPV1 gene for heat sensitivity in small mammals.

Yijung-tang improves thermogenesis and reduces inflammation associated with gut microbiota in hypothyroid rats.

Currently, considerable attention is focused on exploring the potential relationship between herbal medicine (HM) and the gut microbiome in terms of thermoregulation, which is an important aspect of human health, in modern system biology. However, our knowledge of the mechanisms of HM in thermoregulation is inadequate. Here, we demonstrate that the canonical herbal formula, Yijung-tang (YJT), protects against hypothermia, hyperinflammation, and intestinal microbiota dysbiosis in PTU-induced hypothyroid rats. Notably, these properties were associated with alterations in the gut microbiota and signaling crosstalk between the thermoregulatory and inflammatory mediators in the small intestine and brown adipose tissue (BAT). In contrast to the conventional drug L-thyroxine for curing hypothyroidism, YJT has an efficacy for attenuating systematic inflammatory responses, related with depression in intestinal TLR4 and Nod2/Pglyrp1 signaling pathways. Our findings suggest that YJT could promote BAT thermogenesis and prevent systemic inflammation in PTU-induced hypothyroid rats, which was associated with its prebiotic effect on modulating of the gut microbiota and gene expression with relevance in the enteroendocrine function and innate immune systems. These findings may strengthen the rationale of the microbiota-gut-BAT axis for a paradigm shift to enable holobiont-centric medicine.

Efficacy of granulocyte colony-stimulating factor for infertility undergoing IVF: a systematic review and meta-analysis.

OBJECTIVE: This study aimed to evaluate the effectiveness of granulocyte colony-stimulating factor (G-CSF) for infertility and recurrent spontaneous abortion. METHODS: Existing research was searched in PubMed, Embase and Cochrane Library till Dec 2021. Randomized control trials (RCTs) that compared G-CSF administration with the control group in infertility women undergoing IVF were included. The primary outcomes included clinical pregnancy rate; the secondary outcomes included live birth rate, abortion ratebiochemical pregnancy rate, embryo implantation rate, as well as endometrial thickness. RESULT(S): 20 RCTs were included in this study. G-CSF increased the clinical pregnancy rate (RR = 1.85; 95% CI: 1.07, 3.18) and the endometrial thickness (MD = 2.25; 95% CI: 1.58,2.92;) in patients with thin endometrium undergoing IVF. G-CSF increased the biochemical pregnancy rate (RR = 2.12; 95% CI: 1.54, 2.93), the embryo implantation rate (RR = 2.51; 95% CI: 1.82, 3.47) and the clinical pregnancy rate (RR = 1.93; 95% CI: 1.63, 2.29) in patients with a history of repeated implantation failure undergoing IVF. No differences were found in pregnancy outcomes of general IVF patients. CONCLUSIONS: Granulocyte colony-stimulating factor is likely to be a potential option for infertility women undergoing IVF with thin endometrium or recurrent implantation failure . TRIAL REGISTRATION: Retrospectively registered (The PROSPERO registration number: CRD42022360161).

AKTeO2(CO3) (A = Li, Na): The First Carbonatotellurites Featuring a Zero-Dimensional [Te2C2O10]4- Cluster and a Wide Band Gap.

The first carbonatotellurites, AKTeO2(CO3) (A = Li, Na), have been successfully synthesized by using boric acid as the mineralizer. AKTeO2(CO3) (A = Li, Na) crystallize in the monoclinic space group P21/n (no. 14), and their structures exhibit the novel zero-dimensional (0D) [Te2C2O10]4- clusters, in which two [TeO4]4- groups form a [Te2O6]4- dimer via edge-sharing, with each side of the dimer attached by a [CO3]2- group via a Te-O-C bridge. The alkali metal cations occupy the voids between the 0D clusters and maintain the charge balance. The ultraviolet-visible-near-infrared diffuse reflectance spectra show that the short absorption cut-off edges of LiKTeO2(CO3) (LKTC) and NaKTeO2(CO3) (NKTC) are 248 and 240 nm, respectively, and LKTC exhibits the largest experimental band gap (4.58 eV) among all of the tellurites containing the π-conjugated anionic groups reported. Theoretical calculations revealed that they exhibit moderate birefringences of 0.029 and 0.040@1064 nm, respectively.

A new polar alkaline earth-rare earth iodate: Ba2Ce(IO3)8(H2O).

A new alkaline earth-rare earth iodate, Ba2Ce(IO3)8(H2O), has been synthesised by a hydrothermal method and its structure has been determined by single-crystal X-ray diffraction. Ba2Ce(IO3)8(H2O) crystallises in the polar space group Pna21 (No. 33) with unit cell parameters of a = 15.5042(5) Å, b = 7.8841(3) Å, c = 19.5359(8) Å, V = 2388.00(15) Å3, and Z = 4. The structure of Ba2Ce(IO3)8(H2O) is characterised by zero-dimensional (0D) [Ce(IO3)8(H2O)]4- units separated by Ba2+ cations. Large crystals of Ba2Ce(IO3)8(H2O) with dimensions of a few millimetres have been grown. The UV-vis-NIR transmission spectroscopy measurements of the compound showed that it has a short wavelength absorption edge at 381 nm. Ba2Ce(IO3)8(H2O) exhibits a relatively weak second-harmonic-generation (SHG) response, about 0.2 times that of KDP, which is mainly due to the fact that the polarisation effects of the IO3 groups in the structure largely cancel each other out. The relationships between the structure and the physical properties of Ba2Ce(IO3)8(H2O) have also been calculated theoretically. Ba2Ce(IO3)8(H2O) has a band gap of 2.44 eV, which is determined by the Ce-O and I-O interactions and is larger than those of many simple metal iodates. The introduction of alkaline earth metals favours an increase in band gap. Our work shows that the SHG and birefringence properties are closely related to the arrangement of the functional groups in the compounds.

Heterotopic pregnancy after assisted reproductive techniques with favorable outcome of the intrauterine pregnancy: A case report.

BACKGROUND: Heterotopic pregnancy (HP) is a rare condition in which both ectopic and intrauterine pregnancies occur. HP is uncommon after natural conception but has recently received more attention due to the widespread use of assisted reproductive techniques (ART) such as ovulation promotion therapy. CASE SUMMARY: Here, we describe a case of HP that occurred after ART with concurrent tubal and intrauterine singleton pregnancies. This was treated successfully with surgery to preserve the intrauterine pregnancy, resulting in the birth of a low-weight premature infant. This case report aims to increase awareness of the possibility of HP during routine first-trimester ultrasound examinations, especially in pregnancies resulting from ART and even if multiple intrauterine pregnancies are present. CONCLUSION: This case alerts us to the importance of comprehensive data collection during regular consultations. It is important for us to remind ourselves of the possibility of HP in all patients presenting after ART, especially in women with an established and stable intrauterine pregnancy that complain of constant abdominal discomfort and also in women with an unusually raised human chorionic gonadotropin level compared with simplex intrauterine pregnancy. This will allow symptomatic and timeous treatment of patients with better results.

Enhancing extracellular electron transfer through selective enrichment of Geobacter with Fe@CN-modified carbon-based anode in microbial fuel cells.

Microbial fuel cells (MFCs) have been demonstrated as a renewable energy strategy to efficiently recover chemical energy stored in wastewater into clean electricity, yet the limited power density limits their practical application. Here, Fe-doped carbon and nitrogen (Fe@CN) nanoparticles were synthesized by a direct pyrolysis process, which was further decorated to fabricate Fe@CN carbon paper anode. The modified Fe@CN anode with a higher electrochemically active surface area was not only benefit for the adhesion of electrochemically active microorganisms (EAMs) and extracellular electron transfer (EET) between the anode and EAMs but also selectively enriched Geobacter, a typical EAMs species. Accordingly, the MFCs with Fe@CN anode successfully achieved a highest voltage output of 792.76 mV and a prolonged stable voltage output of 300 h based on the mixed culture feeding with acetate. Most importantly, the electroactive biofilms on Fe@CN anode achieved more content ratio of proteins to polysaccharides (1.40) in extracellular polymeric substances for the balance between EET and cell protection under a harsh environment. This work demonstrated the feasibility of development on anode catalysts for the elaboration of the catalytic principle about interface modification, which may contribute to the practical application of MFC in energy generation and wastewater treatment.

Quorum sensing signals improve the power performance and chlortetracycline degradation efficiency of mixed-culture electroactive biofilms.

Electroactive biofilms (EABs) play an important role in bioelectrochemical systems due to their abilities to generate electrons and perform extracellular electron transfer (EET). Here, we investigated the effects of quorum sensing (QS) signals on power output, chlortetracycline degradation, and structure of EABs in MFCs treating antibiotic wastewater. The voltage output of MFCs with C4-HSL and PQS increased by 21.57% and 13.73%, respectively, compared with that without QS signals. The chlortetracycline degradation efficiency in closed-circuit MFCs with C4-HSL and PQS increased by 56.53% and 50.04%, respectively, which resulted from the thicker biofilms, higher biomass, and stronger activities. Additionally, QS signals induced the heterogeneous distribution of EPS for a balance between self-protection and EET under environmental pressure. Geobacter prevailed by the addition of QS signals to resist high chlortetracycline concentration. Our results provided a broader understanding on regulating EABs within electrode interface to improve their performance for environmental remediation and clean energy development.

Is replacing red meat with other protein sources associated with lower risks of coronary heart disease and all-cause mortality? A meta-analysis of prospective studies.

CONTEXT: A high amount of red meat consumption has been associated with higher risks of coronary heart disease (CHD) and all-cause mortality in a single food-exposure model. However, this model may overlook the potentially differential influence of red meat on these outcomes depending on the foods replaced by red meat. OBJECTIVE: A PRISMA-compliant meta-analysis of prospective observational studies was performed to quantify the risks of CHD and all-cause mortality associated with the replacement of total, unprocessed, or processed red meat with fish/seafood, poultry, dairy, eggs, nuts, and legumes. DATA SOURCES: The PubMed and Web of Science databases were searched to identify relevant articles published in any language from database inception to October 30, 2021. DATA EXTRACTION: The prospective observational studies were considered relevant if they reported relative risks (RRs) and 95%CIs for the associations of interest. DATA ANALYSIS: Thirteen articles were included. A random-effects model was used to estimate the summary RRs and 95%CIs for the associations of interest. Replacing total red meat with poultry (RR, 0.88, 95%CI, 0.82-0.96; I2 = 0%), dairy (RR, 0.90, 95%CI, 0.88-0.92; I2 = 0%), eggs (RR, 0.86, 95%CI, 0.79-0.94; I2 = 7.1%), nuts (RR, 0.84, 95%CI, 0.74-0.95; I2 = 66.8%), or legumes (RR, 0.84, 95%CI, 0.74-0.95; I2 = 7.3%) was associated with a lower risk of CHD, whereas substituting fish/seafood (RR, 0.91, 95%CI, 0.79-1.04; I2 = 69.5%) for total red meat was not associated with the risk of CHD. The replacement of total red meat with fish/seafood (RR, 0.92, 95%CI, 0.89-0.96; I2 = 86.9%), poultry (RR, 0.92, 95%CI, 0.90-0.95; I2 = 61.6%), eggs (RR, 0.91, 95%CI, 0.87-0.95; I2 = 33.8%), or nuts (RR, 0.92, 95%CI, 0.87-0.97; I2 = 81.9%) was associated with a lower risk of all-cause mortality, whereas the substitution of dairy (RR, 0.97, 95%CI, 0.93-1.01; I2 = 33.9%) or legumes (RR, 0.97, 95%CI, 0.93-1.01; I2 = 53.5%) for total red meat was not associated with the risk of all-cause mortality. Lower risks of CHD and all-cause mortality were more consistently observed for processed red meat replacements than for unprocessed red meat replacements. The results did not materially change when the analyses of total, processed, and unprocessed red meat were restricted to the studies that used a uniform substitution amount per unit of 1 serving/d. CONCLUSION: Keeping red meat, particularly processed red meat, consumption to a minimum along with increasing healthier alternative protein sources to replace red meat in the diet may contribute to the prevention of CHD and premature death. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration no. CRD42021259446.

The microbiota-gut-kidney axis mediates host osmoregulation in a small desert mammal.

Regulating sodium and water balances is crucial for survival of small, desert mammals. Studies demonstrate that the gut microbiota and their metabolites are involved in host energy homeostasis, but little is known on the interactions among salt loading, gut microbiota, and osmoregulation. The aim of this study was to fill this gap. Mongolian gerbils (Meriones unguiculatus) were offered drinking water (Con) and either water containing moderate (4%, MS) or high NaCl (8%, HS) ad libitum. Intake of HS reduced α diversity of the microbial community and, at the genus level, reduced the relative abundances of Rikenella and Christensenella but increased Atopobium. To confirm the function of gut microbiota in host osmoregulation, we transplanted caecal microbiota in HS gerbils. To cope with salt loading, the gerbils concentrated urine, resulting in negative energy balance and systemic inflammation. The HS gerbils increased hypothalamic arginine vasopressin and intestinal and renal aquaporin 2 to support water retention, and reduced intestinal and renal epithelial sodium channel α to promote sodium excretion. However, HS gerbils with caecal microbiota transplant (CMT) from Con donors maintained energy balance and osmoregulation, and had a much reduced systemic inflammation. Further, CMT from Con donors to HS recipients reshaped the gut microbiota, particularly by reducing Parabacteroides distasonis and Prevotella copri, and increasing Lactobacillus reuteri abundances, with a resulting increase in bacterial metabolites such as butyrate. These findings highlight a vital role of the microbiota-gut-kidney axis in mediating salt-related osmoregulation, allowing small mammals to adapt to high salt loads in a desert habitat.

Gut Microbial Community and Host Thermoregulation in Small Mammals.

The endotherms, particularly the small mammals living in the polar region and temperate zone, are faced with extreme challenges for maintaining stable core body temperatures in harsh cold winter. The non-hibernating small mammals increase metabolic rate including obligatory thermogenesis (basal/resting metabolic rate, BMR/RMR) and regulatory thermogenesis (mainly nonshivering thermogenesis, NST, in brown adipose tissue and skeletal muscle) to maintain thermal homeostasis in cold conditions. A substantial amount of evidence indicates that the symbiotic gut microbiota are sensitive to air temperature, and play an important function in cold-induced thermoregulation, via bacterial metabolites and byproducts such as short-chain fatty acids and secondary bile acids. Cold signal is sensed by specific thermosensitive transient receptor potential channels (thermo-TRPs), and then norepinephrine (NE) is released from sympathetic nervous system (SNS) and thyroid hormones also increase to induce NST. Meanwhile, these neurotransmitters and hormones can regulate the diversity and compositions of the gut microbiota. Therefore, cold-induced NST is controlled by both Thermo-TRPs-SNS-gut microbiota axis and thyroid-gut microbiota axis. Besides physiological thermoregulation, small mammals also rely on behavioral regulation, such as huddling and coprophagy, to maintain energy and thermal homeostasis, and the gut microbial community is involved in these processes. The present review summarized the recent progress in the gut microbiota and host physiological and behavioral thermoregulation in small mammals for better understanding the evolution and adaption of holobionts (host and symbiotic microorganism). The coevolution of host-microorganism symbionts promotes individual survival, population maintenance, and species coexistence in the ecosystems with complicated, variable environments.

Systematic review and meta-analysis of studies in which burrowing behaviour was assessed in rodent models of disease-associated persistent pain.

ABSTRACT: Burrowing behaviour is used to assess pain-associated behaviour in laboratory rodents. To gain insight into how models of disease-associated persistent pain and analgesics affect burrowing behaviour, we performed a systematic review and meta-analysis of studies that assessed burrowing behaviour. A systematic search in March 2020 and update in September 2020 was conducted in 4 databases. Study design characteristics and experimental data were extracted, followed by a random-effects meta-analysis. We explored the association between burrowing and monofilament-induced limb withdrawal. Dose response relationship was investigated for some analgesics. Forty-five studies were included in the meta-analysis, in which 16 model types and 14 drug classes were used. Most experiments used rat (79%) and male (72%) animals. Somatic inflammation and trauma-induced neuropathy models were associated with reduced burrowing behaviour. Analgesics (nonsteroidal anti-inflammatory drug and gabapentinoids) attenuated burrowing deficits in these models. Reporting of measures to reduce risk of bias was unclear except for randomisation which was high. There was not a correlation ( R2 = 0.1421) between burrowing and monofilament-induced limb withdrawal. Opioids, gabapentin, and naproxen showed reduced burrowing behaviour at high doses, whereas ibuprofen and celecoxib showed opposite trend. The findings indicate that burrowing could be used to assess pain-associated behaviour. We support the use of a portfolio of composite measures including spontaneous and stimulus-evoked tests. The information collected here could help in designing experiments involving burrowing assessment in models of disease-associated pain.