Objective To explore the polymorphism of tyrosinase (TYR) and melanocortin 1 receptor (MC1R) genes and their mRNA expression levels in relation to coat-color phenotypes in guinea pigs, providing genetic markers for locating dominant traits in guinea pigs. Methods A total of 57 self-bred ordinary-level guinea pigs were selected and divided into three groups based on coat color: white (n=22), variegated (n=22) and black (n=13). The guinea pigs were euthanized with an overdose of pentobarbital sodium via intraperitoneal injection. DNA was then extracted from the dorsal skin tissue. Polymorphism in the coding sequence (CDS) of the exons of the TYR and MC1R genes in each group was detected by cloning and sequencing. The mRNA expression of the two genes in skin tissues was detected by real-time fluorescent quantitative PCR to investigate the relationship between these genes and guinea pig coat color. Results A single nucleotide polymorphism (SNP) site was found in the CDS region of TYR exon Ⅰ, where the base A was replaced by G. All white guinea pigs had the G/G genotype for TYR, while no deep-colored (variegated and black) guinea pigs exhibited the G/G genotype for TYR. Most deep-colored guinea pigs had the A/A genotype, and a few had A/G genotype. The A/A genotype frequency in black guinea pigs was higher than in variegated guinea pigs. A 2 760 bp sequence deletion was identified in the exon of the MC1R gene, marked as the - gene, with non-deleted samples marked as N gene. Most white guinea pigs had the -/- genotype for MC1R, variegated guinea pigs mainly had the -/N genotype, and black guinea pigs mainly had the N/N genotype, with a few showing the -/N. The TYR gene expression level was higher in white guinea pigs, lower in variegated guinea pigs, and intermediate in black guinea pigs, but there was no significant difference among the three groups (P>0.05). The MC1R gene expression level in white guinea pigs was extremely low, while both variegated and black guinea pigs showed significantly higher levels than white guinea pigs (P<0.01). Black guinea pigs showed significantly higher levels than variegated guinea pigs (P<0.05). ConclusionThe TYR and MC1R genes synergistically regulate coat color of guinea pigs. The G-site mutation in the TYR gene may lead to albinism, and the change of N-site in the MC1R gene affects the depth of the coat color.

ObjectiveThe utilization of assisted reproductive technology to rescue genetically modified mouse strains with reproductive disorders provides a reference for improving techniques to preserve valuable experimental mouse strains. MethodsIn vitro fertilization-embryo transfer (IVF-ET) technology was performed on 28 strains of infertile male mice aged 9-18 months. Several indicators such as sperm density and sperm motility in infertile male mice were assessed to select the most viable sperm for IVF-ET experiments. Fertility rate, abnormal egg rate, and birth rate were recorded after the birth of the pups. An optimized ovarian transplantation procedure was applied to 12 strains of infertile female mice aged 8-18 months. 6-week-old female mice with the same genetic background were selected as recipients. One intact ovary was removed from each recipient mouse, and the contralateral oviduct was ligated. An ovary from a donor mouse was isolated and transplanted orthotopically into the side where the ovary had been removed in the recipient mouse. Twenty-one days post-surgery, recipient mice were co-housed with 8-week-old wild type male mice of the same genetic background for breeding. Data such as the pregnancy rate and live birth rate of the recipients were recorded after the birth of the pups. ResultsIVF-ET successfully rescued 28 mouse strains, with the oldest male mice being 18 months old. The success rate of the first round of IVF-ET experiments was 89.29% (25/28). The average fertility rate of IVF in infertile male mice was (51.01±14.97)%, the abnormal egg rate was (9.03±5.28)%, and the birth rate of offspring mice was (18.60±7.03)%. 39 out of 40 ovarian transplant recipient mice survived, with a pregnancy rate of 33.33% (13/39) for ovarian transplant recipients, and a live birth rate of 17.95% (7/39). Four mouse strains were successfully rescued using optimized ovarian transplantation technology, with the oldest female mice being 18 months old. 8 strains were not rescued as they failed to produce offspring that survived to sexual maturity. ConclusionIVF-ET is an effective approach for rescuing mice with reproductive disorders caused by different reasons, especially for those beyond the optimal breeding age. Ovarian transplantation technology can also be used as an alternative for aged female mice. But its success rate is relatively lower than that of IVF-ET, and carries a higher experimental risk.

BACKGROUND:Carnosic acid,a bioactive compound found in rosemary,has been shown to reduce inflammation and reactive oxygen species(ROS).However,its mechanism of action in osteoclast differentiation remains unclear. OBJECTIVE:To investigate the effects of carnosic acid on osteoclast activation,ROS production,and mitochondrial function. METHODS:Primary bone marrow-derived macrophages from mice were extracted and cultured in vitro.Different concentrations of carnosic acid(0,10,15,20,25 and 30 μmol/L)were tested for their effects on bone marrow-derived macrophage proliferation and toxicity using the cell counting kit-8 cell viability assay to determine a safe concentration.Bone marrow-derived macrophages were cultured in graded concentrations and induced by receptor activator of nuclear factor-κB ligand for osteoclast differentiation for 5-7 days.The effects of carnosic acid on osteoclast differentiation and function were then observed through tartrate-resistant acid phosphatase staining,F-actin staining,H2DCFDA probe and mitochondrial ROS,and Mito-Tracker fluorescence detection.Western blot and RT-PCR assays were subsequently conducted to examine the effects of carnosic acid on the upstream and downstream proteins of the receptor activator of nuclear factor-κB ligand-induced MAPK signaling pathway. RESULTS AND CONCLUSION:Tartrate-resistant acid phosphatase staining and F-actin staining showed that carnosic acid dose-dependently inhibited in vitro osteoclast differentiation and actin ring formation in the cell cytoskeleton,with the highest inhibitory effect observed in the high concentration group(30 μmol/L).Carnosic acid exhibited the most significant inhibitory effect during the early stages(days 1-3)of osteoclast differentiation compared to other intervention periods.Fluorescence imaging using the H2DCFDA probe,mitochondrial ROS,and Mito-Tracker demonstrated that carnosic acid inhibited cellular and mitochondrial ROS production while reducing mitochondrial membrane potential,thereby influencing mitochondrial function.The results of western blot and RT-PCR revealed that carnosic acid could suppress the expression of NFATc1,CTSK,MMP9,and C-fos proteins associated with osteoclast differentiation,and downregulate the expression of NFATc1,Atp6vod2,ACP5,CTSK,and C-fos genes related to osteoclast differentiation.Furthermore,carnosic acid enhanced the expression of antioxidant enzyme proteins and reduced the generation of ROS during the process of osteoclast differentiation.Overall,carnosic acid exerts its inhibitory effects on osteoclast differentiation by inhibiting the phosphorylation modification of the P38/ERK/JNK protein and activating the MAPK signaling pathway in bone marrow-derived macrophages.

BACKGROUND:Total knee arthroplasty serves as an effective intervention for the treatment of late-stage knee joint disorders.However,prosthetic liners are prone to wear and failure due to internal stress variations,resulting in limited lifespan and decreased postoperative patient activity.Addressing how to enhance prosthetic design to meet a broader range of patient needs constitutes a significant focus in prosthesis research. OBJECTIVE:Based on the morphological design of the meniscus,we propose an asymmetric design prosthesis and compare it with a symmetric posterior stabilized prosthesis.The stress distribution patterns and variations in the contact area of the liners for both prostheses were analyzed to explore whether the asymmetric prosthesis design offers advantages over the symmetric design. METHODS:Using the finite element method,we simulated the osteotomy and prosthesis assembly in a knee osteoarthritis patient.Two different prostheses(asymmetric design and posterior stabilized)were employed to establish post-total knee arthroplasty knee joint models.Under flexion conditions at 0°,10°,20°,and 30°,we investigated the Mises stress on the femoral and tibial components as well as the liner.Additionally,by comparing the contact area on the inner and outer sides of the liner,we aimed to explore the changes in biomechanics and alterations in motion behavior in the post-total knee arthroplasty knee joint. RESULTS AND CONCLUSION:(1)Throughout the flexion range from 0 to 30 degrees,the Mises stress peak on the liner exhibited a trend of initial decrease followed by an increase,with the stress on the medial side consistently surpassing that on the lateral side.(2)In comparison to the posterior stabilized prosthesis,the asymmetrically designed prosthesis demonstrated smaller stress peaks.At a flexion angle of 30 degrees,the Mises stress peak values of the medial and lateral parts of the asymmetric prosthesis were 15.81 MPa and 11.95 MPa,and those of the posterior stabilization prosthesis were 16.70 MPa and 13.76 MPa.The difference of Mises stress on the medial part was 5.33%,and the difference of Mises stress on the lateral part was 13.15%.Comparing the peak Mises stress on the femoral and tibial components,the asymmetric component was always lower than the posterior stable component during knee flexion.(3)In the upright position at 0 degrees,the medial contact area of the posterior stabilization prosthesis was 17.96 mm2,and the lateral contact area was 34.10 mm2.The contact area on the inner and outer sides of the asymmetric design prosthesis liner was 105.47 mm2 and 107.80 mm2,respectively,indicating a larger contact area with a smaller difference between the inner and outer sides.(4)These results suggest that the biomechanical performance of the asymmetric prosthesis is superior,contributing to the maintenance of knee joint stability and improved joint mobility.This design,to a certain extent,mimics the rotational motion mechanism of the knee joint about the medial condyle as an axis,making it a more effective choice for knee joint prosthesis selection.

BACKGROUND:Stand-alone oblique lateral interbody fusion has a high rate of complications of fusion segment sink.Oblique lateral interbody fusion with posterior fixation can provide stable support,but intraoperative position changes and double incisions weaken the advantages of this technique.Oblique lateral interbody fusion combined with lateral plate fixation can achieve one-stage decompression in the same incision,while the lateral internal fixation provides stable support. OBJECTIVE:To analyze the short-term efficacy of oblique lateral interbody fusion combined with lateral plate fixation in the treatment of single-level lumbar degenerative disease. METHODS:The clinical data of 34 patients with single-level lumbar degenerative disease treated with oblique lateral interbody fusion combined with lateral plate fixation were collected from May 2020 to October 2022.Among them,14 were males and 20 were females aged from 41 to 72 years at the mean age of(58.6±9.9)years.There were 11 cases of lumbar spondylolisthesis(Ⅰ°),7 cases of lumbar disc herniation with segmental instability,and 16 cases of lumbar spinal stenosis.Operation time,blood loss,and complications were recorded.Visual analog scale scores of lumbago,radiative pain of both lower limbs,and Oswestry disability index scores were evaluated before surgery,3 months after surgery,and the last follow-up.Dural sac cross-sectional area,intervertebral height,and intervertebral fusion were measured and observed. RESULTS AND CONCLUSION:(1)The 34 patients were followed up for 14-36 months,with an average of(21.3±5.2)months.(2)The operation time ranged from 50 to 92 minutes,with an average of(68.5±11.1)minutes.Intraoperative blood loss was 50-170 mL,with an average of(71.6±25.3)mL.(3)Compared with the preoperative results,the visual analog scale scores and Oswestry disability index scores were significantly decreased at 3 months after surgery and at the last follow-up(P<0.001),and the maximum Oswestry disability index scores were improved by nearly 50％.(4)Bone fusion was achieved in all patients during half-year follow-up.The overall complication rate was 21％(7/34),including 1 case of plate displacement,3 cases of cage subsidence,1 case of psoas weakness,and 2 cases of anterior thigh pain.(5)It is concluded that oblique lateral interbody fusion combined with lateral plate fixation for the treatment of lumbar degenerative diseases has the characteristics of less blood loss,short operation time,rapid postoperative recovery,and significant short-term clinical efficacy with the stable support to a certain extent.The long-term curative effect needs further follow-up observation.

BACKGROUND:Degenerative scoliosis is defined as a condition that occurs in adulthood with a coronal cobb angle of the spine>10° accompanied by sagittal deformity and rotational subluxation,which often produces symptoms of spinal cord and nerve compression,such as lumbar pain,lower limb pain,numbness,weakness,and neurogenic claudication.The finite element method is a mechanical analysis technique for computer modelling,which can be used for spinal mechanics research by building digital models that can realistically restore the human spine model and design modifications. OBJECTIVE:To review the application of finite element method in the etiology and treatment of degenerative scoliosis. METHODS:The literature databases CNKI,PubMed,and Web of Science were searched for articles on the application of finite element method in degenerative scoliosis published before October 2023.Search terms were"finite element analysis,biomechanics,stress analysis,degenerative scoliosis,adult spinal deformity"in Chinese and English.Fifty-four papers were finally included. RESULTS AND CONCLUSION:(1)The biomechanical findings from the degenerative scoliosis model constructed using the finite element method were identical to those from the in vivo experimental studies,which proves that the finite element method has a high practical value in degenerative scoliosis.(2)The study of the etiology and treatment of degenerative scoliosis by the finite element method is conducive to the prevention of the occurrence of the scoliosis,slowing down the progress of the scoliosis,the development of a more appropriate treatment plan,the reduction of complications,and the promotion of the patients'surgical operation.(3)The finite element method has gradually evolved from a single bony structure to the inclusion of soft tissues such as muscle ligaments,and the small sample content is increasingly unable to meet the research needs.(4)The finite element method has much room for exploration in degenerative scoliosis.

BACKGROUND:The regeneration and remodeling of Achilles tendon rupture after surgery are difficulties in clinical treatment.Tissue engineering hydrogels afford the possibility on the healing of postoperative Achilles tendon. OBJECTIVE:To investigate the effect of tannic acid modified interpenetrating network hydrogel on tissue regeneration and remodeling of ruptured Achilles tendon in rats. METHODS:(1)The interpenetrating network hydrogel was prepared under the blue light and the immersion of CaSO4 solution.The micromorphology,mechanical properties,adhesion properties,in vitro drug release properties,and biocompatibility of hydrogels were characterized.(2)Thirty Sprague-Dawley rats were randomly divided into sham operation group,operation group,and hydrogel group,with 10 rats in each group.The animal model of Achilles tendon rupture was established in the latter two groups.In the operation group,the ruptured Achilles tendon was sutured using the modified Kessler method.In the hydrogel group,the ruptured Achilles tendon was repaired by the same method,and the tannic acid modified interpenetrating network hydrogel patch was completely wrapped around the joint of the broken end.Four weeks after the operation,imaging examination,histological evaluation,biomechanical test,and the level test of inflammatory factors were performed. RESULTS AND CONCLUSION:(1)Scanning electron microscope showed that tannic acid modified interpenetrating network hydrogels had porous microstructure with pore size of 3-10 μm,and the hydrogels had good in vitro drug release properties,adhesion strength and tensile strength.CCK-8 assay and live/dead staining showed that the hydrogel had no significant effect on the proliferation activity of rat bone marrow mesenchymal stem cells,and had good biocompatibility.(2)MRI imaging showed that compared with the operation group,the Achilles tendon in the hydrogel group showed uniform low signal,the thickness of the anteroposterior diameter of the Achilles tendon was reduced,and the boundary between the Achilles tendon and the surrounding tissue was more clear,and the performance was more similar to that of the sham operation group.Hematoxylin-eosin staining and Masson staining showed that the tendon fibers in the operation group were arranged in a loose and chaotic manner,with increased cell density and disordered arrangement,accompanied by obvious inflammatory cell infiltration,and intratendinous ossification appeared in some areas.In the hydrogel group,the tendon fibers were arranged in an orderly manner;the cell density was reduced and arranged orderly;the inflammatory cell infiltration was significantly reduced.The tensile strength of Achilles tendon in the operation group was lower than that in the sham operation group(P<0.05).The tensile strength of Achilles tendon in the hydrogel group was higher than that in the operation group(P<0.05).Compared with sham operation group,the mass concentration and mRNA expression of interleukin-1β,interleukin-6,and tumor necrosis factor α in Achilles tendon of rats were increased in the operation group(P<0.05).Compared with the operation group,the level and mRNA expression of three inflammatory factors were decreased in the hydrogel group.(3)It is concluded that tannic acid modified interpenetrating network hydrogel can inhibit the local inflammatory response and promote the tendon remodeling.

BACKGROUND:Previous studies have found that neohesperidin can delay bone loss in ovariectomized mice and has the potential to treat osteoporosis,but its specific mechanism of action remains to be explored. OBJECTIVE:To explore the key targets and possible mechanisms of neohesperidin in the treatment of osteoporosis based on bioinformatics and cell experiments in vitro. METHODS:The gene expression dataset related to osteoporosis was obtained from GEO database,and the differentially expressed genes were screened and analyzed in R language.The osteoporosis-related targets were screened from GeneCards and DisGeNET databases,and the neohesperidin-related targets were screened from ChEMBL and PubChem databases,and the common targets were obtained by intersection of the three.The String database was used to construct the PPI network of intersection genes,and the key targets were screened.The DAVID database was used for GO and KEGG enrichment analysis.The AutoDock software was used to verify the molecular docking between the neohesperidin and the target protein.The effect of neohesperidin on osteogenic differentiation of C57 mouse bone marrow mesenchymal stem cells was detected.Complete medium was used as blank control group;osteogenic induction medium was used as the control group;and osteogenic induction medium containing different concentrations of neohesperidin(25,50 μmol/L)was used as experimental group.The expression of alkaline phosphatase,the degree of mineralization,the expression of osteogenic-related genes and target genes during osteogenic differentiation of cells were measured at corresponding time points. RESULTS AND CONCLUSION:(1)9 253 differentially expressed genes,2 161 osteoporosis-related targets,and 326 neohesperidin-related targets were screened.There were 53 common targets among the three.All 53 genes were up-regulated in osteoporosis samples.The PPI network screened the target gene PRKACA of research significance.GO function and KEGG pathway enrichment analysis showed that neohesperidin's treatment of osteoporosis through PRKACA target mainly depended on biological processes such as protein phosphorylation and protein autophosphorylation,acting on endocrine resistance,proteoglycan in cancer,and estrogen signaling pathway to play a therapeutic role.Molecular docking results showed that neohesperidin had a certain binding ability to the protein corresponding to the target PRKACA.(2)The results of alkaline phosphatase staining showed that neohesperidin could promote the expression of alkaline phosphatase in the early stage of osteogenic differentiation of mesenchymal stem cells.Alizarin red staining showed that neohesperidin could promote the mineralization of osteogenic differentiation of mesenchymal stem cells.RT-qPCR results showed that neohesperidin could increase the mRNA expression of alkaline phosphatase,PRKACA,and osteocalcin.(3)These results indicate that neohesperidin may promote osteogenic differentiation through PRKACA target on the estrogen signaling pathway to prevent and treat osteoporosis.

Neoadjuvant therapy has become the standard treatment for locally advanced resectable esophageal cancer, significantly improving long-term survival compared to surgery alone. Neoadjuvant therapy has evolved to include various strategies, such as concurrent chemoradiotherapy, chemotherapy, immunotherapy, or targeted combination therapy. This enriches clinical treatment options and provides a more personalized and scientific treatment approach for patients. This article aims to comprehensively summarize current academic research hot topics, review the rationale and evaluation measures of neoadjuvant therapy, discuss challenges in restaging methods after neoadjuvant therapy, and identify the advantages and disadvantages of various neoadjuvant therapeutic strategies.

With the continuous development of China's aging society and the prevalence of unhealthy lifestyles, the incidence of cardiovascular disease in China has been increasing in recent years. Among them, atrial fibrillation (AF) is the most common arrhythmia disease. In recent years, pulsed field ablation (PFA) has been continuously applied to AF treatment as a novel treatment. This paper first introduces the principle of PFA applied to AF treatment, and introduces the research progress of PFA in different directions, such as the comparison of different ablation methods, the study of physical parameters, the study of ablation area, the study of tissue specificity and clinical research. Then, the clinical prior research of PFA is discussed, including the use of simulation software to obtain the simulation effect of different parameters, the evaluation of ablation effect during animal research, and finally the current AF treatment. Various prior studies and clinical studies are summarized, and suggestions are made for the shortcomings found in the study of AF treatment and the future research direction is prospected.