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 analyze the clinical characteristics of children with head and neck rhabdomyosarcoma (RMS) and to summarize the mid-long term efficacy of Beijing Children′s Hospital Rhabdomyosarcoma 2006 (BCH-RMS-2006) regimen and China Children′s Cancer Group Rhabdomyosarcoma 2016 (CCCG-RMS-2016) regimen.Methods:A retrospective cohort study. Clinical data of 137 children with newly diagnosed head and neck RMS at Beijing Children′s Hospital, Capital Medical University from March 2013 to December 2021 were collected. Clinical characteristic of patients at disease onset and the therapeutic effects of patients treated with the BCH-RMS-2006 and CCCG-RMS-2016 regimens were compared. The treatments and outcomes of patients with recurrence were also summarized. Survival analysis was performed by Kaplan-Meier method, and Log-Rank test was used for comparison of survival rates between groups.Results:Among 137 patients, there were 80 males (58.4%) and 57 females (41.6%), the age of disease onset was 59 (34, 97) months. The primary site in the orbital, non-orbital non-parameningeal, and parameningeal area were 10 (7.3%), 47 (34.3%), and 80 (58.4%), respectively. Of all patients, 32 cases (23.4%) were treated with the BCH-RMS-2006 regimen and 105 (76.6%) cases were treated with the CCCG-RMS-2016 regimen. The follow-up time for the whole patients was 46 (20, 72) months, and the 5-year progression free survival (PFS) and overall survival (OS) rates for the whole children were (60.4±4.4)% and (69.3±4.0)%, respectively. The 5-year OS rate was higher in the CCCG-RMS-2016 group than in BCH-RMS-2006 group ((73.0±4.5)% vs. (56.6±4.4)%, χ2=4.57, P=0.029). For the parameningeal group, the 5-year OS rate was higher in the CCCG-RMS-2016 group (61 cases) than in BCH-RMS-2006 group (19 cases) ((57.3±7.6)% vs. (32.7±11.8)%, χ2=4.64, P=0.031). For the group with meningeal invasion risk factors, the 5-year OS rate was higher in the CCCG-RMS-2016 group (54 cases) than in BCH-RMS-2006 group (15 cases) ((57.7±7.7)% vs. (30.0±12.3)%, χ2=4.76, P=0.029). Among the 10 cases of orbital RMS, there was no recurrence. In the non-orbital non-parameningeal RMS group (47 cases), there were 13 (27.6%) recurrences, after re-treatment, 7 cases survived. In the parameningeal RMS group (80 cases), there were 40 (50.0%) recurrences, with only 7 cases surviving after re-treatment. Conclusions:The overall prognosis for patients with orbital and non-orbital non-parameningeal RMS is good. However, children with parameningeal RMS have a high recurrence rate, and the effectiveness of re-treatment after recurrence is poor. Compared with the BCH-RMS-2006 regimen, the CCCG-RMS-2016 regimen can improve the treatment efficacy of RMS in the meningeal region.

The accumulation of uremic toxins such as urea nitrogen, blood creatinine, and uric acid of patients with renal failure in vivo would lead to aggravated kidney damage. In this study, coated aldehyde oxy-starch (CAO) was used as an adsorbent to investigate its in vitro adsorption performance on renal failure indexes for urea, indoxyl sulfate (INS), monomethylamine (MMA), dimethylamine (DMA), uric acid (UA), and creatinine (Cr). The effects of variables such as pH, temperature, concentration, dosage, and time on the adsorption capacity of CAO were systematically investigated, employing analytical techniques of high-performance liquid chromatography (HPLC) and gas chromatography (GC). The results revealed that CAO exhibited a strong adsorption capacity for urea, INS, and MMA, alongside a moderate adsorption capacity for DMA, UA, and Cr. The adsorption kinetics and thermodynamic studies indicated that the adsorption of urea and UA by CAO were fitted in pseudo-first-order kinetics, and the adsorption isotherm aligned with the Freundlich adsorption model. The enthalpy change ΔH of urea in adsorption was in the range of 40 to 60 kJ·mol^-1, which demonstrated the presence of strong adsorption force due to the interactions of coordinating groups. The ΔH of UA was greater than 80 kJ·mol^-1, indicating the generation of chemical bonds during the adsorption. Both of them, Gibbs free energy ΔG was less than 0, within the range of -20 to 0 kJ·mol^-1, suggested that the adsorption of urea and UA by CAO occurred spontaneously as physical adsorption process. The adsorption entropy ΔS of urea and UA was > 0, which indicated an increase in entropy throughout the adsorption. The infrared spectroscopygram showed the formation of a chemical bond, specifically the imine bond, following the adsorption of urea by CAO, thereby indicating a chemical reaction during the adsorption. This study elucidates the adsorption mechanism of CAO on various indexes of renal failure, providing a scientific basis for its clinical usage.

ObjectiveTo investigate the mechanism of Naoxintong capsules on ischemia-reperfusion （I/R） injury in rats based on the changes of pericytes mediated by Ras homolog family member A （RHOA）/Rho-associated coiled-coil containing protein kinase 1 （ROCK1） pathway. MethodsNinety rats （15 rats for each group） were randomly divided into a sham operation group， a model group， a positive control group receiving Ginkgo biloba extract （21.6 mg·kg^-1）， and groups receiving Naoxintong capsules at low， medium， and high doses of 55， 110， and 220 mg·kg^-1 （NXT-L， NXT-M， and NXT-H groups）， respectively. Except for those in the sham operation group， all rats were subjected to transient middle cerebral artery occlusion （tMCAO） to establish the experiment model. Nerve function was assessed using a neurological function score. Cerebral blood flow was detected using a laser speckle contrast imager， and the cerebral infarction rate was calculated using 2，3，5-Triphenyl tetrazolium chloride （TTC） staining. Pathological changes were observed by hematoxylin-eosin （HE） staining and Nissl staining， while pericyte morphology was observed via transmission electron microscopy. Blood-brain barrier destruction was observed by Evans blue staining. Albumin and ischemia-modified albumin levels were measured using assay kits. Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） and Western blot were used to detect the mRNA and protein expression levels of RHOA， ROCK1， platelet-derived growth factor receptor β （PDGFRB）， α-smooth muscle actin （α-SMA）， tight junction protein （ZO-1）， matrix metalloproteinase-2 （MMP-2）， and matrix metalloproteinase-9 （MMP-9）. ResultsCompared with the sham operation group， the model group exhibited decreased neurological function scores， higher percentage reduction in blood flow， and increased cerebral infarction rates （P<0.01）. Additionally， cortical neuronal nucleus shrinkage， edema， a decreased number of Nissl bodies， reduced pericyte area， elevated albumin content in the cortex （P<0.05）， and increased ischemic modified albumin levels （P<0.01） were observed. The mRNA and protein expression levels of RHOA， ROCK1， PDGFRB， α-SMA， MMP-2， and MMP-9 were increased （P<0.01）， while those of ZO-1 were decreased. Compared with the model group， all treatment groups showed improved neurological function scores， lower percentage reduction in blood flow， reduced cerebral infarction rates （P<0.01）， alleviated cortical histological changes， increased number of Nissl bodies， expanded pericyte area， decreased albumin content in the cortex， and reduced ischemia-modified albumin levels （P<0.01）. The mRNA and protein expression levels of RHOA， ROCK1， PDGFRB， α-SMA， MMP-2， and MMP-9 were decreased （P<0.01）， while those of ZO-1 were increased. Among the treatment groups， the NXT-M group showed the most pronounced improvement in cerebral I/R injury. ConclusionNaoxintong capsules can restore cerebral blood supply， reduce microcirculation disturbance， and protect blood-brain barrier in rats with I/R injury. Its mechanism of action may be related to the inhibition of the RHOA/ROCK1 signaling pathway and reduced pericyte contraction.

ObjectiveTo investigate the mechanism of Naoxintong capsules on ischemia-reperfusion （I/R） injury in rats based on the changes of pericytes mediated by Ras homolog family member A （RHOA）/Rho-associated coiled-coil containing protein kinase 1 （ROCK1） pathway. MethodsNinety rats （15 rats for each group） were randomly divided into a sham operation group， a model group， a positive control group receiving Ginkgo biloba extract （21.6 mg·kg^-1）， and groups receiving Naoxintong capsules at low， medium， and high doses of 55， 110， and 220 mg·kg^-1 （NXT-L， NXT-M， and NXT-H groups）， respectively. Except for those in the sham operation group， all rats were subjected to transient middle cerebral artery occlusion （tMCAO） to establish the experiment model. Nerve function was assessed using a neurological function score. Cerebral blood flow was detected using a laser speckle contrast imager， and the cerebral infarction rate was calculated using 2，3，5-Triphenyl tetrazolium chloride （TTC） staining. Pathological changes were observed by hematoxylin-eosin （HE） staining and Nissl staining， while pericyte morphology was observed via transmission electron microscopy. Blood-brain barrier destruction was observed by Evans blue staining. Albumin and ischemia-modified albumin levels were measured using assay kits. Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） and Western blot were used to detect the mRNA and protein expression levels of RHOA， ROCK1， platelet-derived growth factor receptor β （PDGFRB）， α-smooth muscle actin （α-SMA）， tight junction protein （ZO-1）， matrix metalloproteinase-2 （MMP-2）， and matrix metalloproteinase-9 （MMP-9）. ResultsCompared with the sham operation group， the model group exhibited decreased neurological function scores， higher percentage reduction in blood flow， and increased cerebral infarction rates （P<0.01）. Additionally， cortical neuronal nucleus shrinkage， edema， a decreased number of Nissl bodies， reduced pericyte area， elevated albumin content in the cortex （P<0.05）， and increased ischemic modified albumin levels （P<0.01） were observed. The mRNA and protein expression levels of RHOA， ROCK1， PDGFRB， α-SMA， MMP-2， and MMP-9 were increased （P<0.01）， while those of ZO-1 were decreased. Compared with the model group， all treatment groups showed improved neurological function scores， lower percentage reduction in blood flow， reduced cerebral infarction rates （P<0.01）， alleviated cortical histological changes， increased number of Nissl bodies， expanded pericyte area， decreased albumin content in the cortex， and reduced ischemia-modified albumin levels （P<0.01）. The mRNA and protein expression levels of RHOA， ROCK1， PDGFRB， α-SMA， MMP-2， and MMP-9 were decreased （P<0.01）， while those of ZO-1 were increased. Among the treatment groups， the NXT-M group showed the most pronounced improvement in cerebral I/R injury. ConclusionNaoxintong capsules can restore cerebral blood supply， reduce microcirculation disturbance， and protect blood-brain barrier in rats with I/R injury. Its mechanism of action may be related to the inhibition of the RHOA/ROCK1 signaling pathway and reduced pericyte contraction.

Objectives: This study evaluates the efficacy of a new temporomandibular joint (TMJ) capsule suspension technique for stabilizing the TMJ after free fibular flap reconstruction of the mandibular condyle. Patients and Methods: Patients undergoing the TMJ capsule suspension technique during free fibular flap reconstruction after mandibulectomy with condylectomy (study group; n=9) were compared with a control group (n=9). Mandibular movement trajectory and surface electromyographic signals of bilateral masseters were recorded. The neocondyle–disc relationship was examined with magnetic resonance imaging (MRI) at 6 months after surgery. Results: Maximal mouth opening and bilateral marginal movement distances were comparable between the two groups (P>0.05). The asymmetry index of the condyle path length was significantly higher in controls (P=0.02). Bilateral mouth opening trajectories were symmetric in 7 patients and deviated to the affected side in 2 patients in the study group; they deviated to the affected side in all controls. The mean electromyographic values of the masseter on the affected side in resting, maximum bite, and chewing states were comparable between the two groups (P=0.13, P=0.65, and P=0.82, respectively). On MRI at 6 months, the thicknesses of the anterior, medial, and posterior bands and TMJ disc length were similar on the affected and normal sides in the study group (P=0.57, P=0.13, P=0.48, and P=0.87, respectively). Conclusion The proposed TMJ capsule suspension technique could improve postoperative TMJ structure and function after fibular free flap reconstruction following mandibulectomy with condylectomy.

Objectives: This study evaluates the efficacy of a new temporomandibular joint (TMJ) capsule suspension technique for stabilizing the TMJ after free fibular flap reconstruction of the mandibular condyle. Patients and Methods: Patients undergoing the TMJ capsule suspension technique during free fibular flap reconstruction after mandibulectomy with condylectomy (study group; n=9) were compared with a control group (n=9). Mandibular movement trajectory and surface electromyographic signals of bilateral masseters were recorded. The neocondyle–disc relationship was examined with magnetic resonance imaging (MRI) at 6 months after surgery. Results: Maximal mouth opening and bilateral marginal movement distances were comparable between the two groups (P>0.05). The asymmetry index of the condyle path length was significantly higher in controls (P=0.02). Bilateral mouth opening trajectories were symmetric in 7 patients and deviated to the affected side in 2 patients in the study group; they deviated to the affected side in all controls. The mean electromyographic values of the masseter on the affected side in resting, maximum bite, and chewing states were comparable between the two groups (P=0.13, P=0.65, and P=0.82, respectively). On MRI at 6 months, the thicknesses of the anterior, medial, and posterior bands and TMJ disc length were similar on the affected and normal sides in the study group (P=0.57, P=0.13, P=0.48, and P=0.87, respectively). Conclusion The proposed TMJ capsule suspension technique could improve postoperative TMJ structure and function after fibular free flap reconstruction following mandibulectomy with condylectomy.

Objectives: This study evaluates the efficacy of a new temporomandibular joint (TMJ) capsule suspension technique for stabilizing the TMJ after free fibular flap reconstruction of the mandibular condyle. Patients and Methods: Patients undergoing the TMJ capsule suspension technique during free fibular flap reconstruction after mandibulectomy with condylectomy (study group; n=9) were compared with a control group (n=9). Mandibular movement trajectory and surface electromyographic signals of bilateral masseters were recorded. The neocondyle–disc relationship was examined with magnetic resonance imaging (MRI) at 6 months after surgery. Results: Maximal mouth opening and bilateral marginal movement distances were comparable between the two groups (P>0.05). The asymmetry index of the condyle path length was significantly higher in controls (P=0.02). Bilateral mouth opening trajectories were symmetric in 7 patients and deviated to the affected side in 2 patients in the study group; they deviated to the affected side in all controls. The mean electromyographic values of the masseter on the affected side in resting, maximum bite, and chewing states were comparable between the two groups (P=0.13, P=0.65, and P=0.82, respectively). On MRI at 6 months, the thicknesses of the anterior, medial, and posterior bands and TMJ disc length were similar on the affected and normal sides in the study group (P=0.57, P=0.13, P=0.48, and P=0.87, respectively). Conclusion The proposed TMJ capsule suspension technique could improve postoperative TMJ structure and function after fibular free flap reconstruction following mandibulectomy with condylectomy.

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.

ObjectiveTobacco-related diseases remain one of the leading preventable public health challenges worldwide and are among the primary causes of premature death. In recent years, accumulating evidence has supported the classification of nicotine addiction as a chronic brain disease, profoundly affecting both brain structure and function. Despite the urgency, effective diagnostic methods for smoking addiction remain lacking, posing significant challenges for early intervention and treatment. To address this issue and gain deeper insights into the neural mechanisms underlying nicotine dependence, this study proposes a novel graph neural network framework, termed TI-GNN. This model leverages functional magnetic resonance imaging (fMRI) data to identify complex and subtle abnormalities in brain connectivity patterns associated with smoking addiction. MethodsThe study utilizes fMRI data to construct functional connectivity matrices that represent interaction patterns among brain regions. These matrices are interpreted as graphs, where brain regions are nodes and the strength of functional connectivity between them serves as edges. The proposed TI-GNN model integrates a Transformer module to effectively capture global interactions across the entire brain network, enabling a comprehensive understanding of high-level connectivity patterns. Additionally, a spatial attention mechanism is employed to selectively focus on informative inter-regional connections while filtering out irrelevant or noisy features. This design enhances the model’s ability to learn meaningful neural representations crucial for classification tasks. A key innovation of TI-GNN lies in its built-in causal interpretation module, which aims to infer directional and potentially causal relationships among brain regions. This not only improves predictive performance but also enhances model interpretability—an essential attribute for clinical applications. The identification of causal links provides valuable insights into the neuropathological basis of addiction and contributes to the development of biologically plausible and trustworthy diagnostic tools. ResultsExperimental results demonstrate that the TI-GNN model achieves superior classification performance on the smoking addiction dataset, outperforming several state-of-the-art baseline models. Specifically, TI-GNN attains an accuracy of 0.91, an F1-score of 0.91, and a Matthews correlation coefficient (MCC) of 0.83, indicating strong robustness and reliability. Beyond performance metrics, TI-GNN identifies critical abnormal connectivity patterns in several brain regions implicated in addiction. Notably, it highlights dysregulations in the amygdala and the anterior cingulate cortex, consistent with prior clinical and neuroimaging findings. These regions are well known for their roles in emotional regulation, reward processing, and impulse control—functions that are frequently disrupted in nicotine dependence. ConclusionThe TI-GNN framework offers a powerful and interpretable tool for the objective diagnosis of smoking addiction. By integrating advanced graph learning techniques with causal inference capabilities, the model not only achieves high diagnostic accuracy but also elucidates the neurobiological underpinnings of addiction. The identification of specific abnormal brain networks and their causal interactions deepens our understanding of addiction pathophysiology and lays the groundwork for developing targeted intervention strategies and personalized treatment approaches in the future.