Clemastine-induced enhancement of hippocampal myelination alleviates memory impairment in mice with chronic pain.

Patients with chronic pain often experience memory impairment, but the underlying mechanisms remain elusive. The myelin sheath is crucial for rapid and accurate action potential conduction, playing a pivotal role in the development of cognitive abilities in the central nervous system. The study reveals that myelin degradation occurs in the hippocampus of chronic constriction injury (CCI) mice, which display both chronic pain and memory impairment. Using fiber photometry, we observed diminished task-related neuronal activity in the hippocampus of CCI mice. Interestingly, the repeated administration with clemastine, which promotes myelination, counteracts the CCI-induced myelin loss and reduced neuronal activity. Notably, clemastine specifically ameliorates the impaired memory without affecting chronic pain in CCI mice. Overall, our findings highlight the significant role of myelin abnormalities in CCI-induced memory impairment, suggesting a potential therapeutic approach for treating memory impairments associated with neuropathic pain.

Efficacy and safety of perioperative application of ketamine on postoperative depression: A meta-analysis of randomized controlled studies.

Ketamine, a commonly used general anesthetic, can produce rapid and sustained antidepressant effect. However, the efficacy and safety of the perioperative application of ketamine on postoperative depression remains uncertain. We performed a meta-analysis to determine the effect of perioperative intravenous administration of ketamine on postoperative depression. Randomized controlled trials comparing ketamine with placebo in patients were included. Primary outcome was postoperative depression scores. Secondary outcomes included postoperative visual analog scale (VAS) scores for pain and adverse effects associated with ketamine. Fifteen studies with 1697 patients receiving ketamine and 1462 controls were enrolled. Compared with the controls, the ketamine group showed a reduction in postoperative depression scores, by a standardized mean difference (SMD) of -0.97, 95% confidence interval [CI, -1.27, -0.66], P < 0.001, I2 = 72% on postoperative day (POD) 1; SMD-0.65, 95% CI [-1.12, -0.17], P < 0.001, I2 = 94% on POD 3; SMD-0.30, 95% CI [-0.45, -0.14], P < 0.001, I2 = 0% on POD 7; and SMD-0.25, 95% CI [-0.38, -0.11], P < 0.001, I2 = 59% over the long term. Ketamine reduced VAS pain scores on POD 1 (SMD-0.93, 95% CI [-1.58, -0.29], P = 0.005, I2 = 97%), but no significant difference was found between the two groups on PODs 3 and 7 or over the long term. However, ketamine administration distinctly increased the risk of adverse effects, including nausea and vomiting (risk ratio [RR] 1.40, 95% CI [1.12, 1.75], P = 0.003, I2 = 30%), headache (RR 2.47, 95% CI [1.41, 4.32], P = 0.002, I2 = 19%), hallucination (RR 15.35, 95% CI [6.24, 37.34], P < 0.001, I2 = 89%), and dizziness (RR 3.48, 95% CI [2.68, 4.50], P < 0.001, I2 = 89%) compared with the controls. In conclusion, perioperative application of ketamine reduces postoperative depression and pain scores with increased risk of adverse effects.

Contribution of activating lateral hypothalamus-lateral habenula circuit to nerve trauma-induced neuropathic pain in mice.

Neuropathic pain, a severe clinical symptom, significantly affects the quality of life in the patients. The molecular mechanisms underlying neuropathic pain have been the focus of research in recent decades; however, the neuronal circuit-mediated mechanisms associated with this disorder remain poorly understood. Here, we report that a projection from the lateral hypothalamus (LH) glutamatergic neurons to the lateral habenula (LHb), an excitatory LH-LHb neuronal circuit, participates in nerve injury-induced nociceptive hypersensitivity. LH glutamatergic neurons are activated and display enhanced responses to normally non-noxious stimuli following chronic constriction injury. Chemogenetic inhibition of LH glutamatergic neurons or excitatory LH-LHb circuit blocked CCI-induced nociceptive hypersensitivity. Activation of the LH-LHb circuit led to augmented responses to mechanical and thermal stimuli in mice without nerve injury. These findings suggest that LH neurons and their triggered LH-LHb circuit participate in central mechanisms underlying neuropathic pain and may be targets for the treatment of this disorder.

Stage-, dose-, and course-dependent inhibition of prenatal amoxicillin exposure on fetal articular cartilage development in fetal mice.

Amoxicillin is widely used in the treatment of infectious diseases during pregnancy; however, the effects of prenatal amoxicillin exposure (PAE) on fetal development remain largely unknown. Therefore, this study aimed to investigate the toxic effects of PAE on fetal cartilage at different stage-, dose-, and course. Pregnant Kunming mice were orally administered 300 mg/kg·d (converted from clinical dose) amoxicillin on gestational days (GD) 10-12 or 16-18 (mid or late pregnancy stage), 150 or 300 mg/kg.d amoxicillin on GD16-18 (different doses), 300 mg/kg·d amoxicillin on GD16 (single course) or 16-18 (multiple courses), respectively. The fetal articular cartilage of the knee was collected on GD18. The number of chondrocytes and the expression of matrix synthesis/degradation, proliferation/apoptosis-related markers, and the TGF-ß signaling pathway were detected. The results showed that the number of chondrocytes and the expression of matrix synthesis markers were reduced in male fetal mice treated with PAE (GD16-18, 300 mg/kg.d, single course and multiple courses), whereas the above indices in female mice showed no changes. The inhibited expression of PCNA, increased expression of Caspase-3, and down-regulated expression of the TGF-ß signaling pathway were found in male PAE fetal mice. Accordingly, PAE exerted its "toxic effect window" on the knee cartilage development in male fetal mice, which manifested as reduced chondrocyte number and inhibited expression of matrix synthesis at a clinical dose of multiple courses in the late pregnancy stage. This study provides a theoretical and experimental basis for elucidating the risk of chondrodevelopmental toxicity associated with amoxicillin during pregnancy.

Integrated Proteomic and Phosphoproteomic Analysis of the Hippocampus in a Mouse Model of Early Life Inflammation.

INTRODUCTION: Inflammation in early life is a risk factor for the development of neuropsychiatric diseases later in adolescence and adulthood, yet the underlying mechanism remains elusive. In the present study, we performed an integrated proteomic and phosphoproteomic analysis of the hippocampus to identify potential molecular mechanisms of early life inflammation-induced cognitive impairment. METHODS: Both female and male mice received a single intraperitoneal injection of 100 µg/kg lipopolysaccharide (LPS) on postnatal day 10 (P10). Behavioral tests, including open field, elevated plus-maze, and Y-maze tests, were performed on P39, P40, and P41, respectively. After behavioral tests, male mice were sacrificed. The whole brain tissues and the hippocampi were harvested on P42 for proteomic, phosphoproteomic, Western blot, and Golgi staining. RESULTS: Early life LPS exposure induced cognitive impairment in male mice but not in female mice, as assessed by the Y-maze test. Therefore, following biochemical tests were conducted on male mice. By proteomic analysis, 13 proteins in LPS group exhibited differential expression. Among these, 9 proteins were upregulated and 4 proteins were downregulated. For phosphoproteomic analysis, a total of 518 phosphopeptides were identified, of which 316 phosphopeptides were upregulated and 202 phosphopeptides were downregulated in the LPS group compared with the control group. Furthermore, KEGG analysis indicated that early life LPS exposure affected the glutamatergic synapse and neuroactive ligand-receptor interaction, which were associated with synaptic function and energy metabolism. Increased level of brain protein i3 (Bri3), decreased levels of PSD-95 and mGLUR5, and dendritic spine loss after early life LPS exposure further confirmed the findings of proteomic and phosphoproteomic analysis. CONCLUSIONS: Our findings demonstrated that neuroinflammation and impaired synapse may be involved in early life inflammation-induced cognitive impairment. Future studies are required to confirm our preliminary results.

Melanin-like polydopamine nanoparticles mediating anti-inflammatory and rescuing synaptic loss for inflammatory depression therapy.

Inflammatory depression is closely related to neuroinflammation. However, current anti-inflammatory drugs have low permeability to cross blood-brain barrier with difficulties reaching the central nervous system to provide therapeutic effectiveness. To overcome this limitation, the nano-based drug delivery technology was used to synthesize melanin-like polydopamine nanoparticles (PDA NPs) (~ 250 nm) which can cross the blood-brain barrier. Importantly, PDA NPs with abundant phenolic hydroxyl groups function as excellent free radical scavengers to attenuate cell damage caused by reactive oxygen species or acute inflammation. In vitro experiments revealed that PDA NPs exhibited excellent antioxidative properties. Next, we aimed to investigate the therapeutic effect of PDA NPs on inflammatory depression through intraperitoneal injection to the lipopolysaccharide-induced inflammatory depression model in mice. PDA NPs significantly reversed the depression-like behavior. PDA NPs was also found to reduce the peripheral and central inflammation induced by LPS, showing that alleviated splenomegaly, reduced serum inflammatory cytokines, inhibited microglial activation and restored synaptic loss. Various experiments also showed that PDA NPs had good biocompatibility both in vivo and in vitro. Our work suggested that PDA NPs may be biocompatible nano-drugs in treating inflammatory depression but their clinical application requires further study.

Meropenem-loaded Cement Is Effective in Preventing Gram-negative Osteomyelitis in an Animal Model.

BACKGROUND: Low-dose antibiotic-loaded acrylic cement is routinely used for preventing skeletal infection or reimplantation in patients with periprosthetic joint infections. However, few reports about the selection of antibiotics in acrylic cement for antigram-negative bacteria have been proposed. QUESTIONS/PURPOSES: (1) Does the addition of antibiotics (tobramycin, meropenem, piperacillin, ceftazidime, ciprofloxacin, and aztreonam) to acrylic cement adversely affect compressive strength before and after elution? (2) Which antibiotics have the highest cumulative release within 28 days? (3) Which antibiotics showed antimicrobial activity within 28 days? (4) Does meropenem-loaded cement improve body weight, temperature, and other inflammatory markers compared with control unloaded cement? METHODS: This is an in vitro study that assessed the mechanical strength, antibiotic elution, and antibacterial properties of antibiotic-loaded cement, combined with an animal study in a rat model that evaluated key endpoints from the animal study. In the in vitro study, we added 2 g of tobramycin (TOB), meropenem (MEM), piperacillin (PIP), ceftazidime (CAZ), ciprofloxacin (CIP), and aztreonam (ATM) to 40 g of acrylic cement. The compressive strength, elution, and in vitro antibacterial properties of the antibiotic-loaded cement were detected. Thirty male rats were randomly divided into two groups: CON (antibiotic-unloaded cement) and MEM (meropenem-loaded cement, which had the most stable antibacterial properties of the six tested antibiotic-loaded cements in vitro within 28 days). The right tibia of all rats underwent arthroplasty and was implanted with the cement, followed by inoculation with Pseudomonas aeruginosa in the knee. General status, serum biomarkers, radiology, microbiological assay, and histopathological tests were assessed over 14 days postoperatively. RESULTS: The compressive strength of all tested antibiotic cement combinations exceeded the 70 MPa threshold (the requirement established in ISO 5833). The cumulative release proportions of the raw antibiotic in cement were 1182.8 ± 37.9 µg (TOB), 355.6 ± 16.2 µg (MEM), 721.2 ± 40.3 µg (PIP), 477.4 ± 37.1 µg (CAZ), 146.5 ± 11.3 µg (CIP), and 372.1 ± 14.5 µg (ATM) within 28 days. Over a 28-day period, meropenem cement demonstrated antimicrobial activities against the four tested gram-negative bacteria ( Escherichia coli , P. aeruginosa , Klebsiella pneumoniae , and Proteus vulgaris ). Ciprofloxacin cement inhibited E. coli growth, ceftazidime and aztreonam cement inhibited K. pneumonia growth, and tobramycin cement inhibited P. aeruginosa . Only meropenem demonstrated antimicrobial activity against all gram-negative bacteria on agar diffusion bioassay. Rats treated with meropenem cement showed improved body weight (control: 280.1 ± 4.2 g, MEM: 288.5 ± 6.6 g, mean difference 8.4 [95% CI 4.3 to 12.6]; p < 0.001), improved knee width (control: 13.5 ± 0.3 mm, MEM: 11.8± 0.4 mm, mean difference 1.7 [95% CI 1.4 to 2.0]; p < 0.001), decreased inflammatory marker (control: 316.7 ± 45.0 mm, MEM: 116.5 ± 21.8 mm, mean difference 200.2 [95% CI 162.3 to 238.2]; p < 0.001), decreased radiographic scores (control: 17.7 ± 2.0 mm, MEM: 10.7± 1.3 mm, mean difference 7.0 [95% CI 5.4 to 8.6]; p < 0.001), improved bone volume/total volume (control: 8.7 ± 3.0 mm, MEM: 28.5 ± 5 .5 mm, mean difference 19.8 [95% CI 13.3 to 26.2]; p < 0.001), decreased Rissing scale scores of the knee gross pathology (control: 3.3 ± 0.5, MEM: 1.1 ± 0.7, mean difference 2.2 [95% CI 1.7 to 2.7]; p < 0.001), decreased Petty scale scores of knee synovium (control: 2.9 ± 0.4 mm, MEM: 0.7 ± 0.7 mm, mean difference 2.1 [95% CI 1.7 to 2.5]; p < 0.001), and decreased bacterial counts of the bone and soft tissues and negative bacterial cultures of cement (p < 0.001, p < 0.001, p < 0.001, p < 0.001, respectively). CONCLUSION: In this current study, MEM cement had the most stable in vitro antimicrobial activities, effective in vivo activity while having acceptable mechanical and elution characteristics, and it may be an effective prophylaxis against skeletal infection caused by gram-negative bacteria. CLINICAL RELEVANCE: Meropenem-loaded acrylic cement is a potentially effective prevention measure for skeletal infection caused by gram-negative bacteria; however, more related clinical research is needed to further evaluate the safety and efficacy.

Peiminine regulates bone-fat balance by canonical Wnt/ß-catenin pathway in an ovariectomized rat model.

Peiminine is a major biologically active component of Fritillaria thunbergii Miq that exhibits good anticancer, antiinflammatory, and anti-osteoclast effects. However, its effects on osteoporosis (OP) remain unknown. This study aimed to explore whether Peiminine was able to regulate osteogenesis and adipogenesis in ovariectomized (OVX) rat. The effects on the differentiation of bone marrow stem cells (BMSCs), function of Wnt/ß-catenin pathway, ALP activity, calcium nodule deposition, as well as adipocyte formation in vitro by Peiminine at different concentrations, were detected. The curative effects of Peiminine on the ovariectomy-induced osteoporosis model by micro-CT and bone histomorphology assays were analyzed. The promotion of osteogenic differentiation and inhibition of adipogenic differentiation by Peiminine (5-40 µg/mL) was detected and the optimum concentration was 20 µg/mL. Mechanistically, Peiminine regulated the fate of BMSCs in vitro, and activated Wnt/ß-catenin signaling pathway by restraining phosphorylation of ß-catenin and promoting the nuclear translocation of ß-catenin. Moreover, Peiminine prevented ovariectomy-induced osteoporosis by alleviating trabecular bone loss and inhibiting adipose formation. Our data suggested that Peiminine could attenuate ovariectomy-induced osteoporosis by alleviating trabecular bone loss and inhibiting adipose formation. These encouraging discoveries could lay the foundation for Peiminine to be a promising preventive treatment strategy for skeletal diseases, such as osteoporosis.

Evaluation of Experimental and Clinical Efficacy on Surgical Debridement and Systemic Antibiotics Treatment for Early Knee Infection after Anterior Cruciate Ligament Reconstruction.

Deep knee infection (DKI) after anterior cruciate ligament reconstruction (ACLR) is rare and challenging. The optimal treatment strategy for infection after ACLR remains controversial. This study aimed to investigate the optimal treatment for early infection after ACLR surgery. Rats with unilateral ACLR were injected with 3.0 × 105 colony forming units (CFU) of Staphylococcus aureus in the knee joint for 7 days. Next, with surgical debridement (SD) and/or 21 days of antimicrobial (systemic vancomycin and oral rifampicin [SVR]) therapy, rats were euthanatized and samples harvested. We evaluated signs of infection by general postoperative conditions, serum inflammatory markers, microbiological counting, knee radiographs, micro-computed tomography (micro-CT), histologic staining, and scanning electron microscopy (SEM). Clinically, the data from 12 patients who suffered from DKI after ACLR were analyzed retrospectively. The DKI rats treated with SVR showed better outcomes in general postoperative conditions, serum inflammatory markers, microbiological counting, biofilm on the interference screw and graft, radiographic signs of periarticular osseous destruction, and inflammatory reaction in the joint tissues than those with SD treatment, while the DKI rats with SD and SVR administration showed the best outcomes. Rats which received SD and SVR administration had their S. aureus contamination completely eradicated. All patients treated with SD & SVR or SVR alone had effectively controlled knee infections and achieved good knee function outcomes in the 6 months after treatment, but one patient developed more serious knee infections. Therefore, surgical debridement combined with systemic antibiotics treatment could effectively eliminate S. aureus contamination in the DKI rat model and in patients after ACLR without affecting knee function. Treatment with systemic antibiotics could also control early DKI, which would be especially applicable in patients who could not tolerate surgery.

MZF1 in the Dorsal Root Ganglia Contributes to the Development and Maintenance of Neuropathic Pain via Regulation of TRPV1.

Previous studies have demonstrated that myeloid zinc finger 1 (MZF1) in the dorsal root ganglion (DRG) participates in neuropathic pain induced by chronic-constriction injury (CCI) via regulation of voltage-gated K+ channels (Kv). Emerging evidence indicates that transient receptor potential vanilloid 1 (TRPV1) is involved in the development and maintenance of neuropathic pain. Although it is known that the transcription of TRPV1 is regulated by Kruppel-like zinc-finger transcription factor 7 (Klf7)-and that the structure of TRPV1 is similar to that of Kv-few studies have systematically investigated the relationship between MZF1 and TRPV1 in neuropathic pain. In the present study, we demonstrated that CCI induced an increase in MZF1 and TRPV1 in lumbar-level 4/5 (L4/5) DRGs at 3 days post-CCI and that this increase was persistent until at least 14 days post-CCI. DRG microinjection of rAAV5-MZF1 into the DRGs of naïve rats resulted in a decrease in paw-withdrawal threshold (PWT) and paw-withdrawal latency (PWL) compared with that of the rAAV5-EGFP group, which started at four weeks and lasted until at least eight weeks after microinjection. Additionally, prior microinjection of MZF1 siRNA clearly ameliorated CCI-induced reduction in PWT and PWL at 3 days post-CCI and lasted until at least 7 days post-CCI. Correspondingly, microinjection of MZF1 siRNA subsequent to CCI alleviated the established mechanical allodynia and thermal hyperalgesia induced by CCI, which occurred at 3 days postinjection and lasted until at least 10 days postinjection. Microinjection of rAAV5-MZF1 increased the expression of TRPV1 in DRGs. Microinjection of MZF1 siRNA diminished the CCI-induced increase of TRPV1, but not P2X7R, in DRGs. These findings suggest that MZF1 may contribute to neuropathic pain via regulation of TRPV1 expression in DRGs.

TLR4/NF-κB signaling activation in plantar tissue and dorsal root ganglion involves in the development of postoperative pain.

Background Severe postoperative pain remains a clinical problem that impacts patient's rehabilitation. The present work aims to investigate the role of Toll-like receptor-4 (TLR4) activation in wounded plantar tissue and dorsal root ganglion (DRG) in the genesis of postoperative pain and its underlying mechanisms. Results Postoperative pain was induced by plantar incision in rat hind paw. Plantar incision led to increased expression of TLR4 in ipsilateral lumbar 4-5 (L4/L5) DRGs, which occurred at 2 h and was persistent to the third day after surgery. Similar to the change in TLR4 expression, there was also significant increase in phosphorylated nuclear factor-kappa B p65 (p-p65) in DRGs after surgery. Immunofluorescence staining revealed that the increased expressions of TLR4 and p-p65 not only in neuronal cells but also in satellite glial cells in DRG. Furthermore, the enhanced expressions of TLR4 and p-p65 were also detected in plantar tissues around the incision, which was observed starting at 2 h and lasting until the third day after surgery. Prior intrathecal (i.t.) injections of TAK-242 (a TLR4-specific antagonist) or 4',6-diamidino-2-phenylindole-dihydrochloride (PDTC, a nuclear factor-kappa B activation inhibitor) dose dependently alleviated plantar incision-induced mechanical allodynia and thermal hyperalgesia and inhibited the increased expressions of p-p65, tumor necrosis factor-alpha, and interleukin-1 beta in DRG. Prior subcutaneous (s.c.) plantar injection of TAK-242 or PDTC also ameliorated pain-related hypersensitivity following plantar incision. Moreover, the plantar s.c. injection of TAK-242 or PDTC inhibited the increased expressions of p-p65, tumor necrosis factor-alpha, and interleukin-1 beta not only in local wounded plantar tissue but also dramatically in ipsilateral lumbar 4-5 DRGs. Conclusion TLR4/ nuclear factor-kappa B signaling activation in local injured tissue and DRG contribute to the development of postoperative pain via regulating pro-inflammatory cytokines release. Targeting TLR4/ nuclear factor-kappa B signaling in local tissue at early stage of surgery may be an effective strategy for the treatment of postoperative pain.

Dose- and stage-dependent toxic effects of prenatal prednisone exposure on fetal articular cartilage development.

Prednisone is frequently used to treat rheumatoid diseases in pregnant women because of its high degree of safety. Whether prenatal prednisone exposure (PPE) negatively impacts fetal articular cartilage development is unclear. In this study, we simulated a clinical prednisone treatment regimen to examine the effects of different timings and doses of PPE on cartilage development in female and male fetal mice. Prednisone doses (0.25, 0.5, and 1 mg/kg/d) was administered to Kunming mice at different gestational stages (0-9 gestational days, GD0-9), mid-late gestation (GD10-18), or during the entire gestation (GD0-18) by oral gavage. The amount of matrix aggrecan (ACAN) and collagen type II a1(COL2a1), and expression of transforming growth factor ß1 (TGFß1) signaling pathway also demonstrated that the chondrocyte count and ACAN and COL2a1 expression reduced in fetal mice with early and mid-late PPE, with the reduction being more significant in the mice with early PPE than that in those with PPE at other stages. Prenatal exposure to different prednisone doses prevented the reduction of TGFß signaling pathway-related genes [TGFßR1, SMAD family member 3 (Smad3), SRY-box9 (SOX9)] as well as ACAN and COL2a1 mRNA expression levels in fetal mouse cartilage, with the most significant decrease after 1 mg/kg·d PPE. In conclusion, PPE can inhibit/restrain fetal cartilage development, with the greatest effect at higher clinical dose (1 mg/kg·d) and early stage of pregnancy (GD0-9), and the mechanism may be related to TGFß signaling pathway inhibition. The result of this study provide a theoretical and experimental foundation for the rational clinical use of prednisone.

SynCAM1 deficiency in the hippocampal parvalbumin interneurons contributes to sevoflurane-induced cognitive impairment in neonatal rats.

AIMS: Sevoflurane is widely used for general anesthesia in children. Previous studies reported that multiple neonatal exposures to sevoflurane can induce long-term cognitive impairment in adolescent rats, but the underlying mechanisms were not defined. METHODS: Postnatal day 6 (P6) to P8 rat pups were exposed to 30% oxygen with or without 3% sevoflurane balanced with air. The Y maze test (YMT) and Morris water maze (MWM) tests were performed in some cohorts from age P35 to assess cognitive functions, and their brain samples were harvested at age P14, 21, 28, 35, and 42 for measurements of various molecular entities and in vivo electrophysiology experiments at age P35. RESULTS: Sevoflurane exposure resulted in cognitive impairment that was associated with decreased synCAM1 expression in parvalbumin (PV) interneurons, a reduction of PV phenotype, disturbed gamma oscillations, and dendritic spine loss in the hippocampal CA3 region. Enriched environment (EE) increased synCAM1 expression in the PV interneurons and attenuated sevoflurane-induced cognitive impairment. The synCAM1 overexpression by the adeno-associated virus vector in the hippocampal CA3 region restored sevoflurane-induced cognitive impairment, PV phenotype loss, gamma oscillations decrease, and dendritic spine loss. CONCLUSION: Our data suggested that neonatal sevoflurane exposure results in cognitive impairment through decreased synCAM1 expression in PV interneurons in the hippocampus.

Intra-wound versus systemic vancomycin for preventing surgical site infection induced by methicillin-resistant S. aureus after spinal implant surgery in a rat model.

BACKGROUND: Systemic vancomycin administration pre-operatively for the infection prophylaxis of spinal implant surgery remains unsatisfactory. This study aimed to explore the efficacy and dosage of local use of vancomycin powder (VP) in preventing surgical site infections after spinal implant surgery in a rat model. METHODS: Systemic vancomycin (SV; intraperitoneal injection, 88 mg/kg) or intraoperative intra-wound VP (VP0.5: 44 mg/kg, VP1.0: 88 mg/kg, VP2.0: 176 mg/kg) was applied after spinal implant surgery and methicillin-resistant S. aureus (MRSA; ATCC BAA-1026) inoculation in rats. General status, blood inflammatory biomarkers, microbiological and histopathological evaluation were performed during 2 weeks post-surgery. RESULTS: No post-surgical deaths, wound complications and obvious signs of vancomycin adverse effects were observed. Bacterial counts, blood and tissue inflammation were reduced in the VP groups compared with the SV group. VP2.0 group showed better outcomes in weight gain and tissue inflammation than the VP0.5 and VP1.0 group. Microbial counts indicated that no bacteria survived in the VP2.0 group, whereas MRSA was detected in VP0.5 and VP1.0 groups. CONCLUSIONS: Intra-wound VP may be more effective than systemic administration in preventing infection caused by MRSA (ATCC BAA-1026) after spinal implant surgery in a rat model.

Transforming growth factor-ß receptor 1: An intervention target for genetic poor cartilage quality induced by prenatal dexamethasone exposure.

INTRODUCTION: Fetal-originated osteoarthritis is relative to poor cartilage quality and may exhibit transgenerational genetic effects. Previous findings revealed prenatal dexamethasone exposure (PDE) induced poor cartilage quality in offspring. OBJECTIVES: This study focused on further exploring molecular mechanism, heritability, and early intervention of fetal-originated osteoarthritis. METHODS: Pregnant rats (F0) were segregated into control and PDE groups depending upon whether dexamethasone was administered on gestational days (GDs) 9-20. Some female offspring were bred with healthy males during postnatal week (PW) 8 to attain the F2 and F3 generations. The F3-generation rats were administrated with glucosamine intragastrically at PW12 for 6 weeks. The knee cartilages of male and female rats at different time points were harvested to assay their morphologies and functions. Furthermore, primary chondrocytes from the F3-generation rats were isolated to confirm the mechanism and intervention target of glucosamine. RESULTS: Compared with the control, female and male rats in each generation of PDE group showed thinner cartilage thicknesses; shallower and uneven staining; fewer chondrocytes; higher Osteoarthritis Research Society International scores; and lower mRNA and protein expression of SP1, TGFßR1, Smad2, SOX9, ACAN and COL2A1. After F3-generation rats were treated with glucosamine, all of the above changes could be reversed. In primary chondrocytes isolated from the F3-generation rats of PDE group, glucosamine promoted SP1 expression and binding to TGFßR1 promoter to increase the expression of TGFßR1, p-Smad2, SOX9, ACAN and COL2A1, but these were prevented by SB431542 (a potent and selective inhibitor of TGFßR1). CONCLUSIONS: PDE induced chondrodysplasia in offspring and stably inherited in F3-generation rats, which was related to decreased expression of SP1/TGFßR1/Smad2/SOX9 pathway to reduce the cartilage matrix synthesis, without major sex-based variations. Glucosamine could alleviate the poor genetic cartilage quality in offspring induced by PDE by up-regulating SP1/TGFßR1 signaling, which was prevented by a TGFßR1 inhibitor. This study elucidated the molecular mechanism and therapeutic target (TGFßR1) of genetic chondrodysplasia caused by PDE, which provides a research basis for precisely treating fetal-originated osteoarthritis.

The role of the gut-microbiota-brain axis via the subdiaphragmatic vagus nerve in chronic inflammatory pain and comorbid spatial working memory impairment in complete Freund's adjuvant mice.

Chronic inflammatory pain (CIP) is a common public medical problem, often accompanied by memory impairment. However, the mechanisms underlying CIP and comorbid memory impairment remain elusive. This study aimed to examine the role of the gut-microbiota-brain axis in CIP and comorbid memory impairment in mice treated with complete Freund's adjuvant (CFA). 16S rRNA analysis showed the altered diversity of gut microbiota from day 1 to day 14 after CFA injection. Interestingly, fecal microbiota transplantation (FMT) from healthy naive mice ameliorated comorbidities, such as mechanical allodynia, thermal hyperalgesia, spatial working memory impairment, neuroinflammation, and abnormal composition of gut microbiota in the CFA mice. Additionally, subdiaphragmatic vagotomy (SDV) blocked the onset of these comorbidities. Interestingly, the relative abundance of the bacterial genus or species was also correlated with these comorbidities after FMT or SDV. Therefore, our results suggest that the gut-microbiota-brain axis via the subdiaphragmatic vagus nerve is crucial for the development of CIP and comorbid spatial working memory impairment in CFA mice.

Course-, dose-, and stage-dependent toxic effects of prenatal acetaminophen exposure on fetal long bone development.

Acetaminophen is a common analgesic and fever reduction medicine for pregnant women. Epidemiological studies suggest that prenatal acetaminophen exposure (PAcE) affects offspring health and development. However, the effects of PAcE on fetal long bone development and its potential mechanisms have not been elucidated. Based on clinical dosing characteristics, fetal mouse femurs were obtained for detection after oral gavage of acetaminophen at different doses (0, 100 or 400 mg/kg d), courses (single or multiple times) or stages (mid- or late pregnancy) during pregnancy in Kunming mice. The results showed that compared with the control group, PAcE reduced the length of total femur and the primary ossification center (POC), delayed the mineralization of POC and the ossification of epiphyseal region, and down-regulated the mRNA expression of osteogenic function markers (such as Runx2, Bsp, Ocn , Col1a1) in fetal femur, particularly in the high dose, multiple courses, and mid-pregnancy group. Meanwhile, the osteoclast and angiogenic function were also inhibited by PAcE at high dose, multiple courses, and mid-pregnancy, but the inhibition level was less than osteogenic function. Moreover, the alteration of canonical Wnt signalling pathway in PAcE fetal bone were consistent with its osteogenesis function changes. In conclusion, PAcE caused development toxicity and multi-cellular function inhibition in fetal long bone, particularly in the high dose, multiple treatments and mid-pregnancy group, and the alteration of canonical Wnt signalling pathway may be its potential mechanism.

Amniotes co-opt intrinsic genetic instability to protect germ-line genome integrity.

Unlike PIWI-interacting RNA (piRNA) in other species that mostly target transposable elements (TEs), >80% of piRNAs in adult mammalian testes lack obvious targets. However, mammalian piRNA sequences and piRNA-producing loci evolve more rapidly than the rest of the genome for unknown reasons. Here, through comparative studies of chickens, ducks, mice, and humans, as well as long-read nanopore sequencing on diverse chicken breeds, we find that piRNA loci across amniotes experience: (1) a high local mutation rate of structural variations (SVs, mutations ≥ 50 bp in size); (2) positive selection to suppress young and actively mobilizing TEs commencing at the pachytene stage of meiosis during germ cell development; and (3) negative selection to purge deleterious SV hotspots. Our results indicate that genetic instability at pachytene piRNA loci, while producing certain pathogenic SVs, also protects genome integrity against TE mobilization by driving the formation of rapid-evolving piRNA sequences.

Echinacoside Inhibits Osteoclast Function by Down-Regulating PI3K/Akt/C-Fos to Alleviate Osteolysis Caused by Periprosthetic Joint Infection.

Infected osteolysis as a common secondary osteoporosis is associated with excessive osteoclastogenesis and bone resorption. The inhibition of osteoclastogenesis and bone resorption have been demonstrated an effective approach in the treatment of osteolytic diseases. Echinacoside (ECH) is a natural phenylethanoid glycoside with multiple biological functions, including anti-inflammatory, antioxidant, and osteoblast differentiation promotion. However, the effects of ECH on osteoclast differentiation and bone resorption function remain unknown. In vitro, we investigated the effects of ECH on osteoclast differentiation and bone resorption induced by RANKL and its potential mechanisms. In vivo, we established a periprosthetic joint infection (PJI) rat model and demonstrated the changes of infected osteolysis and osteoclasts activities in surgical sites. ECH (20 mg/kg) was injected intraperitoneally after debridement for 4 weeks. Radiological evaluation and bone histomorphometric analysis was performed to assess the efficacy of ECH. The results showed that ECH inhibited osteoclast differentiation, F-actin belts formation, bone resorption function and osteoclast-specific gene expression by preventing NFATc1 translocation, down-regulating its expression and affecting the PI3K/Akt/c-Fos pathway in vitro. ECH also alleviated in vivo PJI-induced osteolysis and maintained bone mass by inhibiting osteoclast activity. Our study indicated that ECH attenuated RANKL-induced osteoclastogenesis and PJI-induced bone loss and was shown as a potentially effective therapeutic agent for osteoclast-related bone diseases.

The miR-98-3p/JAG1/Notch1 axis mediates the multigenerational inheritance of osteopenia caused by maternal dexamethasone exposure in female rat offspring.

As a synthetic glucocorticoid, dexamethasone is widely used to treat potential premature delivery and related diseases. Our previous studies have shown that prenatal dexamethasone exposure (PDE) can cause bone dysplasia and susceptibility to osteoporosis in female rat offspring. However, whether the effect of PDE on bone development can be extended to the third generation (F3 generation) and its multigenerational mechanism of inheritance have not been reported. In this study, we found that PDE delayed fetal bone development and reduced adult bone mass in female rat offspring of the F1 generation, and this effect of low bone mass caused by PDE even continued to the F2 and F3 generations. Furthermore, we found that PDE increases the expression of miR-98-3p but decreases JAG1/Notch1 signaling in the bone tissue of female fetal rats. Moreover, the expression changes of miR-98-3p/JAG1/Notch1 caused by PDE continued from the F1 to F3 adult offspring. Furthermore, the expression levels of miR-98-3p in oocytes of the F1 and F2 generations were increased. We also confirmed that dexamethasone upregulates the expression of miR-98-3p in vitro and shows targeted inhibition of JAG1/Notch1 signaling, leading to poor osteogenic differentiation of bone marrow mesenchymal stem cells. In conclusion, maternal dexamethasone exposure caused low bone mass in female rat offspring with a multigenerational inheritance effect, the mechanism of which is related to the inhibition of JAG1/Notch1 signaling caused by the continuous upregulation of miR-98-3p expression in bone tissues transmitted by F2 and F3 oocytes.