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.

Objective To explore the effects of different concentrations of simvastatin on nerve regeneration after sciatic nerve injury.Methods Rats were randomly divided into the normal group,the control group,the low-dose group and the high-dose group,with 3 rats in each group.Except for the normal group,adult rat sciatic nerve crush injury models were established in the other groups.Rats in the normal group and the control group were orally administered with water,while those in the low-dose group and high-dose group were orally administered with 98%simvastatin at dosages of 4 mg/mL and 40 mg/mL,respectively.The sciatic nerve regeneration in rats was evaluated by sciatic function index(SFI),HE staining,luxol fast blue(LFB)staining and immunofluorescence staining,etc.Results The SFI of rats in the high-dose group 7 days and 14 days after surgery were higher than those in the control group(P<0.05);there was no significant difference in SFI of rats between the low-dose group and the control group 7 days and 14 days after surgery(P>0.05).HE staining and LFB staining results showed that compared with the control group,the number of neurons of rats in the high-dose group increased,the nerve fibers and myelin were clearer and denser,and the nerve function was significantly restored;while no significant improvement was observed in the sciatic nerve of rats in the low-dose group.The immunofluorescence staining results showed that compared with the control group,the immunofluorescence intensity in the high-dose group increased,while that in the low-dose group decreased,the differences were statistically significant(P<0.05).Conclusion High-dose simvastatin can promote peripheral nerve regeneration by regulating the expression of M2 macrophages.

Hepatocellular carcinoma(HCC)is difficult to detect in its early stages and current treatment methods are associated with significant side effects and a high risk of developing drug resistance.This study aims to investigate the effect of phycocyanin(PC)on the apoptosis of human HCC HepG2 cells and its potential mechanism.HepG2 cells were treated with PC at concentrations of 0.1,0.25,0.5,1,2.5,5,and 10 μg/mL for 12 h,and with 10 μg/mL PC and 2.5 μmol/L Wip1 inhibitor(Wip1i)alone or in combination for 12 and 24 h,respectively.Cell proliferation levels were assessed using the CCK-8 cell proliferation-toxicity assay kit.Apoptosis levels were measured by Annexin V-FITC/Propidium Iodide double staining combined with flow cytometry.TMT(Tandem Mass Tag)proteomics quantitative technol-ogy was applied to analyze differential protein expression.Western blotting was used to detect the expres-sion levels of Wip1,p53,and phosphorylated-p53(Ser15)proteins.The CCK-8 assay revealed that PC effectively inhibited HepG2 cell proliferation in a concentration-dependent manner,with a half-maximal inhibitory concentration(IC50)of 19.37 μg/mL.Flow cytometry results showed that PC significantly in-duced apoptosis,with an apoptosis rate of 30.40％.Quantitative proteomics analysis indicated that PC induced activation of the p53 pathway.The CCK-8 assay showed that Wip1i enhanced the cytotoxic effect of PC on HepG2 cells.Western blotting confirmed that PC inhibited Wip1 expression,induced p53 pro-tein phosphorylation,and promoted the expression of total p53 protein.Additionally,Wip1i further en-hanced PC-mediated activation of the p53 pathway,increasing the expression of p53 and pP53(S15).In conclusion,PC may induce apoptosis by inhibiting the activity of the p53 negative regulator Wip1,thereby promoting apoptosis through the Wip1/p53 pathway.

Objective To elucidate the regulatory effects of titanium surface modification on the immune function of immature dendritic cells(imDCs),different crystalline nanomorphologies were constructed on titanium surface to investigate the mechanobiological response of imDCs to nanomorphologies with different crystalline phases.Methods Nanomorphologies with different crystalline phases were constructed on the titanium surface by anodic oxidation and calcination.The changes of the cytoskeleton F-actin,cell adhesion and morphology of imDCs cultured on nanomorphologies with different crystalline phases were observed by fluorescence staining.The relative gene expression of adhesion molecules was detected by quantitative real-time PCR.The migration behaviors of imDCs were observed using real-time live-cell imaging,and the membrane fluidity was detected by fluorescence polarization.Results Nanomorphologies with different crystalline phases,namely amorphous phase,anatase and rutile,were obtained on the titanium surface by anodic oxidation and calcination.The cytoskeleton of imDCs on nanomorphologies with different crystalline phases was remodeled.The spreading area of cells on anatase crystalline phase was relatively small,which was(353.3±148.5)μm2.The number of adherent cells was the largest,which was 587±132.The expression of adhesion molecules such as CD11a,integrin β2,ICAM1,and VCAM1 were also increased in cells which cultured on anatase crystalline phase.The imDCs cultured on anatase crystalline phase were equipped with strong migration ability.The accumulative migration distance was(383.6±177.7)μm,and the Euclidean migration distance was(51.82±50.13)μm.The membrane fluidity was relatively weak,and the fluorescence polarization was 0.348 5±0.041 8.Conclusions imDCs can respond to nanomorphologies with different crystalline phases on the titanium surface and exhibit different biomechanical behaviors.The results might provide a theoretical basis for the design of titanium biomaterials with immunomodulatory functions.

Objective To verify the efficacy of a domestic human DNA quantification kit based on real-time fluorescence quantitative PCR in detecting the total human DNA concentration,male DNA concen-tration in mixed male/female DNA samples,the degree of DNA degradation and inhibitor tolerance.Methods Samples with different concentrations,different male/female ratios,different concentrations of inhibitors,and different degradation degrees were tested using the domestic human DNA quantification kit based on real-time fluorescence quantitative PCR.This kit was compared with a similar product on the market and was applied to the detection of DNA from real cases.Results This human DNA quan-tification kit can effectively detect human DNA as low as 0.001 65 ng/μL,and 6.25 pg/μL of male DNA in mixed samples with a male-to-female ratio of 1∶15 000.Even when the sample contains as high as 400 ng/μL of humic acid or 1 000 μmol/L of hemin alone,the DNA concentration can still be accurately detected.The degradation index can effectively characterize the degradation degree of the sample.This kit has been successfully applied in forensic practice.Conclusion This human DNA quan-tification kit is accurate and reliable in detection.It can accurately reflect the degradation of DNA and inhibitor tolerance.It has good performance in quantitative accuracy,determination of the male/female ratio in mixed samples,and inhibitor tolerance.It has application potential in forensic case examination.

Oligodendrocyte lineage cells, including oligodendrocyte precursor cells (OPCs) and oligodendrocytes (OLs), are essential in establishing and maintaining brain circuits. Autophagy is a conserved process that keeps the quality of organelles and proteostasis. The role of autophagy in oligodendrocyte lineage cells remains unclear. The present study shows that autophagy is required to maintain the number of OPCs/OLs and myelin integrity during brain aging. Inactivation of autophagy in oligodendrocyte lineage cells increases the number of OPCs/OLs in the developing brain while exaggerating the loss of OPCs/OLs with brain aging. Inactivation of autophagy in oligodendrocyte lineage cells impairs the turnover of myelin basic protein (MBP). It causes MBP to accumulate in the cytoplasm as multimeric aggregates and fails to be incorporated into integral myelin, which is associated with attenuated endocytic recycling. Inactivation of autophagy in oligodendrocyte lineage cells impairs myelin integrity and causes demyelination. Thus, this study shows autophagy is required to maintain myelin quality during aging by controlling the turnover of myelin components.
Animals ; Autophagy/physiology* ; Oligodendroglia/metabolism* ; Myelin Sheath/physiology* ; Aging/pathology* ; Myelin Basic Protein/metabolism* ; Cell Lineage/physiology* ; Mice ; Oligodendrocyte Precursor Cells ; Mice, Inbred C57BL ; Brain/cytology* ; Cells, Cultured ; Cell Count

Protrusive facial deformities, characterized by the forward displacement of the teeth and/or jaws beyond the normal range, affect a considerable portion of the population. The manifestations and morphological mechanisms of protrusive facial deformities are complex and diverse, requiring orthodontists to possess a high level of theoretical knowledge and practical experience in the relevant orthodontic field. To further optimize the correction of protrusive facial deformities, this consensus proposes that the morphological mechanisms and diagnosis of protrusive facial deformities should be analyzed and judged from multiple dimensions and factors to accurately formulate treatment plans. It emphasizes the use of orthodontic strategies, including jaw growth modification, tooth extraction or non-extraction for anterior teeth retraction, and maxillofacial vertical control. These strategies aim to reduce anterior teeth and lip protrusion, increase chin prominence, harmonize nasolabial and chin-lip relationships, and improve the facial profile of patients with protrusive facial deformities. For severe skeletal protrusive facial deformities, orthodontic-orthognathic combined treatment may be suggested. This consensus summarizes the theoretical knowledge and clinical experience of numerous renowned oral experts nationwide, offering reference strategies for the correction of protrusive facial deformities.
Humans ; Orthodontics, Corrective/methods* ; Consensus ; Malocclusion/therapy* ; Patient Care Planning ; Cephalometry

Objective To explore the effects of different concentrations of simvastatin on nerve regeneration after sciatic nerve injury.Methods Rats were randomly divided into the normal group,the control group,the low-dose group and the high-dose group,with 3 rats in each group.Except for the normal group,adult rat sciatic nerve crush injury models were established in the other groups.Rats in the normal group and the control group were orally administered with water,while those in the low-dose group and high-dose group were orally administered with 98%simvastatin at dosages of 4 mg/mL and 40 mg/mL,respectively.The sciatic nerve regeneration in rats was evaluated by sciatic function index(SFI),HE staining,luxol fast blue(LFB)staining and immunofluorescence staining,etc.Results The SFI of rats in the high-dose group 7 days and 14 days after surgery were higher than those in the control group(P<0.05);there was no significant difference in SFI of rats between the low-dose group and the control group 7 days and 14 days after surgery(P>0.05).HE staining and LFB staining results showed that compared with the control group,the number of neurons of rats in the high-dose group increased,the nerve fibers and myelin were clearer and denser,and the nerve function was significantly restored;while no significant improvement was observed in the sciatic nerve of rats in the low-dose group.The immunofluorescence staining results showed that compared with the control group,the immunofluorescence intensity in the high-dose group increased,while that in the low-dose group decreased,the differences were statistically significant(P<0.05).Conclusion High-dose simvastatin can promote peripheral nerve regeneration by regulating the expression of M2 macrophages.

Objective To elucidate the regulatory effects of titanium surface modification on the immune function of immature dendritic cells(imDCs),different crystalline nanomorphologies were constructed on titanium surface to investigate the mechanobiological response of imDCs to nanomorphologies with different crystalline phases.Methods Nanomorphologies with different crystalline phases were constructed on the titanium surface by anodic oxidation and calcination.The changes of the cytoskeleton F-actin,cell adhesion and morphology of imDCs cultured on nanomorphologies with different crystalline phases were observed by fluorescence staining.The relative gene expression of adhesion molecules was detected by quantitative real-time PCR.The migration behaviors of imDCs were observed using real-time live-cell imaging,and the membrane fluidity was detected by fluorescence polarization.Results Nanomorphologies with different crystalline phases,namely amorphous phase,anatase and rutile,were obtained on the titanium surface by anodic oxidation and calcination.The cytoskeleton of imDCs on nanomorphologies with different crystalline phases was remodeled.The spreading area of cells on anatase crystalline phase was relatively small,which was(353.3±148.5)μm2.The number of adherent cells was the largest,which was 587±132.The expression of adhesion molecules such as CD11a,integrin β2,ICAM1,and VCAM1 were also increased in cells which cultured on anatase crystalline phase.The imDCs cultured on anatase crystalline phase were equipped with strong migration ability.The accumulative migration distance was(383.6±177.7)μm,and the Euclidean migration distance was(51.82±50.13)μm.The membrane fluidity was relatively weak,and the fluorescence polarization was 0.348 5±0.041 8.Conclusions imDCs can respond to nanomorphologies with different crystalline phases on the titanium surface and exhibit different biomechanical behaviors.The results might provide a theoretical basis for the design of titanium biomaterials with immunomodulatory functions.