Collagen is a major structural protein in the matrix of animal cells and the most widely distributed and abundant functional protein in mammals. Collagen’s good biocompatibility, biodegradability and biological activity make it a very valuable biomaterial. According to the source of collagen, it can be broadly categorized into two types: one is animal collagen; the other is recombinant collagen. Animal collagen is mainly extracted and purified from animal connective tissues by chemical methods, such as acid, alkali and enzyme methods, etc. Recombinant collagen refers to collagen produced by gene splicing technology, where the amino acid sequence is first designed and improved according to one’s own needs, and the gene sequence of improved recombinant collagen is highly consistent with that of human beings, and then the designed gene sequence is cloned into the appropriate vector, and then transferred to the appropriate expression vector. The designed gene sequence is cloned into a suitable vector, and then transferred to a suitable expression system for full expression, and finally the target protein is obtained by extraction and purification technology. Recombinant collagen has excellent histocompatibility and water solubility, can be directly absorbed by the human body and participate in the construction of collagen, remodeling of the extracellular matrix, cell growth, wound healing and site filling, etc., which has demonstrated significant effects, and has become the focus of the development of modern biomedical materials. This paper firstly elaborates the structure, type, and tissue distribution of human collagen, as well as the associated genetic diseases of different types of collagen, then introduces the specific process of producing animal source collagen and recombinant collagen, explains the advantages of recombinant collagen production method, and then introduces the various systems of expressing recombinant collagen, as well as their advantages and disadvantages, and finally briefly introduces the application of animal collagen, focusing on the use of animal collagen in the development of biopharmaceutical materials. In terms of application, it focuses on the use of animal disease models exploring the application effects of recombinant collagen in wound hemostasis, wound repair, corneal therapy, female pelvic floor dysfunction (FPFD), vaginal atrophy (VA) and vaginal dryness, thin endometritis (TE), chronic endometritis (CE), bone tissue regeneration in vivo, cardiovascular diseases, breast cancer (BC) and anti-aging. The mechanism of action of recombinant collagen in the treatment of FPFD and CE was introduced, and the clinical application and curative effect of recombinant collagen in skin burn, skin wound, dermatitis, acne and menopausal urogenital syndrome (GSM) were summarized. From the exploratory studies and clinical applications, it is evident that recombinant collagen has demonstrated surprising effects in the treatment of all types of diseases, such as reducing inflammation, promoting cell proliferation, migration and adhesion, increasing collagen deposition, and remodeling the extracellular matrix. At the end of the review, the challenges faced by recombinant collagen are summarized: to develop new recombinant collagen types and dosage forms, to explore the mechanism of action of recombinant collagen, and to provide an outlook for the future development and application of recombinant collagen.

Alcohol exposure, as a widespread environmental factor, is highly toxic and teratogenic. Embryonic stem cells (ESCs) are pluripotent and key to development, and their gene expression is tightly regulated, allowing the cells to differentiate without self-renewal. Numerous studies showed that alcohol is an important factor affecting the differentiation of ESCs. In this paper, we systematically summarized four major molecular mechanisms underlying alcohol associated differentiation of ESCs: (1) inhibition of the Wnt signaling pathway; (2) restriction of the mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) pathway; (3) alteration of the expression of pluripotent transcription factors; and (4) activation of the nuclear transcriptional program. Through the above mechanisms, alcohol induces aberrant expression of differentiation-related genes and alters the direction of cellular differentiation towards specific lineages, thereby affecting normal embryonic development. Based on the studies on ESCs modeling and other in vitro and in vivo differentiation experiments, the molecular basis of how alcohol affects differentiation by interfering with signaling networks and transcriptional regulation was elucidated, and the results of current research in this field were also summarized, which is crucial for understanding alcohol-mediated toxic effects.

Objective: To investigate the regional differences in the incidence of urothelial carcinoma among kidney transplant recipients between northern and southern China，so as to provide reference for early diagnosis of this disease. Methods: A comprehensive search was conducted across multiple databases，including CNKI，Wanfang，CBM，and PubMed，using the keywords “kidney transplantation” and “tumor” to collect clinical data from qualified kidney transplant centers.The latest and most complete literature data published by 17 transplant centers in northern China and 14 in southern China were included.Statistical analyses were performed to compare the incidence of post-transplant urothelial carcinoma and non-urothelial malignancies. Results: A total of 37 475 kidney transplant recipients were included，among whom 837 (2.23%) developed post-transplant malignancies，including urothelial carcinoma (366/837，43.73%)，non-urothelial carcinoma (444/837，53.05%)，and malignancies with unspecified pathology (27/837，3.23%).The incidence of malignancies was significantly higher in northern China than in southern China [(2.82±1.39)% vs. (1.67±0.83)%，P=0.011]，with a particularly pronounced difference in the incidence of urothelial carcinoma [(1.68±1.12)% vs. (0.32±0.32)%，P<0.001].No significant difference was observed in the incidence of non-urothelial carcinoma between the two regions [(1.11±0.56)% vs. (1.35±0.65)%，P=0.279].Additionally，female transplant recipients exhibited a higher incidence of malignancies than males in both regions (southern China：2.38% vs. 1.80%; northern China：8.93% vs. 2.52%). Conclusion: The incidence of urothelial carcinoma following kidney transplantation is significantly higher in northern China than in southern China，underscoring the importance of implementing regular tumor screening for kidney transplant recipients，particularly for female patients in northern China，to facilitate early diagnosis and timely intervention.

Infertility is a common reproductive disorder affecting millions of couples worldwide. It is estimated that male factors account for about 30%-50% of infertility cases, and some studies have found that the concentration of male sperm gradually decreases over time, a trend that suggests the importance of male fertility. Many factors contribute to the decline of male fertility, among which environmental factors have received widespread attention. After reaching adulthood, spermatogonial stem cells will continue to produce sperm, but these cells exist outside the blood testicular barrier, which makes them highly sensitive to environmental conditions such as air pollution, tobacco smoke, radiation, and heavy metals. It is reported that exposure to these adverse environmental factors not only causes oxidative stress and DNA damage to germ cells, but also leads to abnormal epigenetic modification of sperm DNA, thereby causing a series of diseases. This article reviewed the abnormal methylation changes in DNA associated with exposure to environmental pollutants during spermatogenesis and how these changes affect the quantity, quality, and function of spermatozoa.

ObjectiveJunctophilin-2 (JPH2) is an essential structural protein that maintains junctional membrane complexes (JMCs) in cardiomyocytes by tethering the plasma membrane to the sarcoplasmic reticulum, thereby facilitating excitation-contraction (E-C) coupling. Mutations in JPH2 have been associated with hypertrophic cardiomyopathy (HCM), but the molecular mechanisms governing its membrane-binding properties and the functional relevance of its membrane occupation and recognition nexus (MORN) repeat motifs remain incompletely understood. This study aimed to elucidate the structural basis of JPH2 membrane association and its implications for HCM pathogenesis. MethodsA recombinant N-terminal fragment of mouse JPH2 (residues1-440), encompassing the MORN repeats and an adjacent helical region, was purified under near-physiological buffer conditions.X-ray crystallography was employed to determine the structure of the JPH2 MORN-Helix domain. Sequence conservation analysis across species and junctophilin isoforms was performed to assess the evolutionary conservation of key structural features. Functional membrane-binding assays were conducted using liposome co-sedimentation and cell-based localization studies in COS7 and HeLa cells. In addition, site-directed mutagenesis targeting positively charged residues and known HCM-associated mutations, including R347C, was used to evaluate their effects on membrane interaction and subcellular localization. ResultsThe crystal structure of the mouse JPH2 MORN-Helix domain was resolved at 2.6 Å, revealing a compact, elongated architecture consisting of multiple tandem MORN motifs arranged in a curved configuration, forming a continuous hydrophobic core stabilized by alternating aromatic residues. A C-terminal α-helix further reinforced structural integrity. Conservation analysis identified the inner groove of the MORN array as a highly conserved surface, suggesting its role as a protein-binding interface. A flexible linker segment enriched in positively charged residues, located adjacent to the MORN motifs, was found to mediate direct electrostatic interactions with negatively charged phospholipid membranes. Functional assays demonstrated that mutation of these basic residues impaired membrane association, while the HCM-linked R347C mutation completely abolished membrane localization in cellular assays, despite preserving the overall MORN-Helix fold in structural modeling. ConclusionThis study provides structural insight into the membrane-binding mechanism of the cardiomyocyte-specific protein JPH2, highlighting the dual roles of its MORN-Helix domain in membrane anchoring and protein interactions. The findings clarify the structural basis for membrane targeting via a positively charged linker and demonstrate that disruption of this interaction—such as that caused by the R347C mutation—likely contributes to HCM pathogenesis. These results not only enhance current understanding of JPH2 function in cardiac E-C coupling but also offer a structural framework for future investigations into the assembly and regulation of JMCs in both physiological and disease contexts.

Aim To explore the antimicrobial activity of a novel R-type phage tail-like bacteriocin(PTLB)secreted by Enterobacter cloacae SHAMU191747 a-gainst methicillin-resistant Staphylococcus aureus(MR-SA).Methods Antagonistic activity of E.cloacae SHAMU191747 against MRS A was detected by LB agar plate antagonistic test and LB broth micro-fermentation test.The crude extract of fermentation supernatant of E.cloacae SHAMU191747 was prepared by ultra-high-speed centrifugation and density gradient centrifuga-tion.The novel R-type PTLB in the crude extract was detected by transmission electron microscopy.The an-timicrobial activity of the crude extract against MRSA was verified by LB agar plate spot-seeding method.The molecular weight of the novel R-type PTLB was detected by SDS-PAGE electrophoresis.Results E.cloacae SHAMU191747 secreted a novel R-type PTLB,and had a strong antagonistic effect on MRSA.The no-vel R-type PTLB had a molecular weight of approxi-mately 35 ku and could efficiently kill MRSA.The physical dimensions of its tail-sheath-uncontracted functional molecules were(142.7±4.3)×(13.8±0.6)nm,and those of the tail-sheath-contracted non-functional molecules were(57.7±1.2)×(20.8±1.5)nm.Conclusions The novel R-type PTLB pro-duced by E.cloacae SHAMU191747 can efficiently kill MRSA,and has the potential to be developed into a novel antimicrobial drug with great prospects for clini-cal application.

Aim To examine the neuroprotective im-pacts of total saponins from Trillium tschonoskii maxim(TST)on cerebral ischemia-reperfusion injury(CIRI)in rats and delve into the mechanisms of ferroptosis.Methods The CIRI model was prepared by dividing male SD rats into the model group,TST(0.1 g·kg-1)group,Donepezil hydrochloride(0.45 mg·kg-1)group,and sham group.The cognitive functions of rats in each group were assessed through the Morris water maze test,the changes in neurological function were evaluated using the Zea-Longa method,the infarct area was observed via TTC staining,and the pathologi-cal alterations in brain tissue were analysed using HE and Nissl staining.To further investigate the underly-ing mechanism,the mitochondrial structural changes were examined using transmission electron microscopy,and the levels of GSH-PX,MDA,and SOD were ana-lyzed.Additionally,the expressions of GPX4 and Nrf2 proteins were evaluated through immunohistochemistry and immunofluorescence.Furthermore,the protein lev-els of Keap1/Nrf2/HO-1 and Nrf2/SLC7A11/GPX4 pathways in rats were examined using Western blot-ting.Results The rats in the model group displayed diminished learning and memory capabilities in com-parison to those in the sham group,as well as a signifi-cantly increased cerebral infarction area and higher neurological function scores(P＜0.01),significantly increased cerebral infarct area,disordered and loosely arranged neurons,and reduced Nissl bodies.Addition-ally,mitochondria showed typical signs of ferroptosis.Changes related to ferroptosis included decreased activ-ities of SOD and GSH-PX(P＜0.01)and increased MDA levels(P＜0.01).The expression of GPX4 and Nrf2-positive cells was significantly reduced,along with decreased fluorescence intensity of GPX4.Further-more,the protein expression of Keap1,Nrf2,HO-1,GPX4,SLC7A11 in the hippocampus decreased(P＜0.05,P＜0.01).Following the administration of TST,these effects showed improvement.Conclusions TST has neuroprotective effects,enhancing learning and memory abilities while reducing oxidative stress levels.The mechanism may involve the inhibition of ferroptosis through the Keap-1/Nrf2/HO-1 and Nrf2/SLC7 A11/GPX4 pathways.

Coronary atherosclerotic heart disease(CHD)is an ischemic cardiovascular condition caused by the narrowing or blockage of the vascular lumen due to coronary atherosclerosis.Clinically,it presents as angina pectoris,heart failure,or sud-den cardiac death,and stands as one of the primary causes of mortality among both urban and rural populations in China.Cir-cRNA,classified as non-coding RNAs,can function as upstream regulatory molecules for miRNA or RNA-binding proteins.They actively participate in various pathological processes associated with CHD,including endothelial cell dysfunction,smooth mus-cle cell migration,macrophage-derived foam cell formation,an-giogenesis,myocardial injury,and repair,as well as post-in-farction heart failure.The expression pattern of these molecules is highly specific to the illness and tissue,indicating their poten-tial as therapeutic targets for disease management and as biomar-kers.Furthermore,they also open up new avenues for drug tar-get development in the field of traditional Chinese medicine.This article aims to provide an overview of the recent research progress on circRNA in the regulation of coronary heart disease,as well as the mechanisms involved in traditional Chinese medi-cine.It serves as a valuable reference for future research on cor-onary heart disease.

Objective To explore the clinical efficacy of double beam double tunnel enhanced reconstruction technique in the treatment of knee anterior cruciate ligament(ACL)training injuries.Methods Twenty-nine cases of ACL injury of knee joint from January 2021 to December 2021 were retrospectively analyzed.All the cases were underwent ligament reconstruc-tion surgery.Cases were grouped by surgical technique:there were 14 patients in conventional reconstruction group,including 13 males and 1 female,aged from 22 to 31 years old with an average of(27.07±7.28)years old,autogenous hamstring tendon was used for ligament reconstruction.There were 15 patients in the enhanced reconstruction group,including 13 males and 2 females,aged from 25 to 34 years old with an average of(29.06±4.23)years old,double tunnel ligament reconstruction,the autogenous hamstring muscle was used as the anteromedial bundle,and the posterolateral bundle was replaced by a high-strength line.The difference between knee tibial anterior distance,Lysholm score,International Knee Literature Committee(IKDC)subjective score,Tegner motor level score and visual analog scale(VAS)at 6th and 12th months after the surgery,limb symmetry index(LSI)were recorded at the last follow-up and surgery-related adverse effects during follow-up.Results All patients were followed up,ranged from 13 to 15 months with an average of(13.7±0.8)months.There were no serious adverse reactions related to surgery during the period.There was no statistical difference between the preoperative general data and the observation index of the two groups(P＞0.05).The difference in tibial anterior distance at 6 and 12 months in the enhanced re-construction group(1.45±0.62)mm and(1.74±0.78)mm which were lower those that in the conventional reconstruction group(2.42±0.60)mm and(2.51±0.63)mm(P＜0.05).There was no significant difference in postoperative Lysholm score,Tegner motor level score,IKDC score,VAS,and limb symmetry index at the last follow-up(P＞0.05).Conclusion The enhanced recon-struction technique can more effectively maintain the stability of the knee joint and has no significant effect on the postoperative knee joint function compared with the traditional ligament reconstruction technique.The short-term curative effect is satisfac-tory,and it is suitable for the group with high sports demand.

Objective To compare clinical efficacy of robot-assisted(RA)and remote sensing navigation alignment(RSNA)system-assisted total knee arthroplasty(TKA).Methods From March 2023 to June 2023,60 patients who underwent the first unilateral TKA due to severe knee osteoarthritis(KOA)were admitted and divided into RSNA group and RA group according to different treatment methods,with 30 patients in each group.There were 5 males and 25 females in RSNA group,aged from 56 to 81 years old with an average of(66.33±7.16)years old;body mass index(BM1)ranged from 19.87 to 38.54 kg·m-2 with an average of(28.40±6.18)kg·m-2;the courses of disease ranged from 5 to 36 months with an average of(18.20±8.98)months;RSNA system was used to assist the positioning of osteotomy.There were 7 males and 23 females in RA group,aged from 55 to 82 years old with an average of(67.83±8.61)years old;BMI ranged from 19.67 to 37.25 kg·m-2 with an aver-age of(28.01±4.89)kg·m-2;the courses of disease ranged from 3 to 33 months with an average of(17.93±9.20)months;RA was performed.Operation time,incision length,latent blood loss at 2 weeks after operation and incidence of lower extremity thrombosis were compared between two groups.Hip-knee ankle angle(HKAA),HKAA deviation,lateral distal femoral angle(LDFA),medial proximal tibial angle(MPTA)and posterior tibial slope(PTS)were compared between two groups;Western Ontario McMaster Universities Osteoarthritis Index(WOMAC)and Knee Society score(KSS)were used to evaluate functional recovery before operation,3 and 6 months after operation.Results The operation was performed successfully in both groups,and there were no serious complications such as vascular and nerve injury during operation.The wound healed well at stage Ⅰafter operation,and the follow-up time was 6 months.The operation time,latent blood loss at 2 weeks after operation and inci-sion length in RSNA group were(94.35±5.75)min,(130.54±17.53)mland(14.73±2.14)cm,respectively;while(102.57±6.88)min,(146.33±19.47)ml and(16.78±2.32)cm in RA group,respectively.RSNA group was better than RA group(P＜0.05).No deep vein thrombosis occurred in both groups at 2 weeks after operation,5 patients occurred intermuscular vein throm-bosisin in RSNA group and 8 patients in RA group,the difference was not statistically significant(P＞0.05).In RSNA group,HKAA,LDFA and MPTA were(173.00±5.54)°,(86.96±3.45)°,(82.79±3.35)° before operation,and(178.34±1.85)°,(89.92±0.42)°,(89.84±0.73)° at 1 week after operation,respectively.In RA group,HKAA,LDFA and MPTA were(173.31±6.48)°,(87.15±3.40)° and(82.99±3.05)° before operation,and(178.52±1.79)°,(90.03±0.39)° and(90.15±0.47)° at 1 week after operation,respectively.HKAA,LDFA and MPTA were significantly improved in both groups at 1 week after oper-ation(P＜0.05).There were no significant difference in HKAA,LDFA,MPTA and PTS between two groups before operation and 1 week after operation(P＞0.05).There was no significant difference in deviation distribution of HKAA at 1 week after op-eration(x2=2.61 1,P=0.456).There were no significant difference in WOMAC and KSS between two groups before operation,3 and 6 months after operation(P＞0.05),and postoperative WOMAC and KSS at 3 and 6 months between two groups were im-proved compared with those before operation(P＜0.05).Conclusion Both RA and RSNA system assisted TKA could obtain ac-curate osteotomy,RA has higher surgical accuracy,RSNA system assisted operation has less trauma,and operation is simpler.