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.

This study aims to investigate the therapeutic effects of the Coptidis Rhizoma-Scutellariae Radix on cytokine storm secondary lung injury(CSSLI) induced by CpG1826 in mice, and to elucidate the potential molecular mechanisms by which its major active components, i.e., coptisine and wogonin, alleviate CSSLI by inhibiting the mitochondrial permeability transition pore(mPTP)/nucleotide-binding oligomerization domain-like receptor protein 3(NLRP3) inflammasome pyroptosis pathway. In vivo, a mouse model of CSSLI was established by CpG1826 induction. Pulmonary edema was assessed by lung wet-to-dry weight ratio(W/D), lung injury was evaluated by hematoxylin-eosin(HE) staining, and ultrastructural changes in lung tissue were observed by transmission electron microscopy(TEM). The levels of interleukin(IL)-1β, high mobility group box 1 protein(HMGB1), IL-18, and IL-1α in bronchoalveolar lavage fluid were measured by enzyme-linked immunosorbent assay(ELISA). The results showed that the decoction of the Coptidis Rhizoma-Scutellariae Radix significantly reduced pulmonary edema, alleviated lung injury, and decreased the concentrations of related cytokines in BALF more effectively than either single herb alone, thereby improving CSSLI. In vitro, a CpG1826-induced CSSLI model was established in mouse alveolar macrophage MH-S cells. Calcein-AM quenching was used to screen for the most effective monomer components from the herb pair in inhibiting mPTP opening. Coptisine(5, 10, 20 μmol·L~(-1)) and wogonin(10, 20, 40 μmol·L~(-1)) markedly inhibited mPTP opening, with optimal effects and a clear dose-dependent pattern. These components suppressed mPTP opening, thereby reducing the release of mitochondrial DNA(mtDNA) and the accumulation of reactive oxygen species(ROS), effectively reversing the CpG1826-induced decrease in mitochondrial membrane potential(MMP). Further studies revealed that both coptisine and wogonin inhibited pyroptosis and downregulated the expression of key proteins in the NLRP3/Caspase-1/gasdermin D(GSDMD) pathway. In conclusion, the Coptidis Rhizoma-Scutellariae Radix improves CpG1826-induced CSSLI in mice, and this effect is associated with the inhibition of the mPTP/NLRP3 pyroptosis pathway, providing scientific evidence for its clinical application and further development.
Animals ; Mice ; Drugs, Chinese Herbal/administration & dosage* ; Pyroptosis/drug effects* ; NLR Family, Pyrin Domain-Containing 3 Protein/immunology* ; Male ; Lung Injury/immunology* ; Cytokines/immunology* ; Scutellaria baicalensis/chemistry* ; Oligodeoxyribonucleotides/adverse effects* ; Mice, Inbred C57BL ; Coptis chinensis

Myocardial infarction (MI) is the leading cause of cardiovascular disease-related death worldwide. Nonetheless, existing therapeutic approaches for MI are hampered by issues such as reliance on pharmacological agents and suboptimal patient adherence. Caffeic acid (CA) is a bioactive polyphenolic compound with important anti-inflammatory, anti-bacterial and anti-oxidant functions. Still, its specific role and mechanism in treating cardiovascular disease remain to be further studied. In recent years, a large number of studies have shown that the kelch-like ECH-associated protein 1/nuclear factor erythroid 2 related factor 2 (Keap1/Nrf2) pathway is a key factor in the occurrence and development of cardiovascular diseases. In this study, H₂O₂-induced oxidative stress model of H9c2 cells and left anterior descending branch (LAD) conjunctival induced acute myocardial infarction reperfusion (AMI/R) model were used to evaluate the protective effect of CA on the heart. The interaction between CA and Keap1 was analyzed by CA-labeled fluorescence probe, target fishing, isothermal titration calorimetry (ITC), protein crystallography and surface plasmon resonance (SPR). Our results suggested that CA binds Keap1 and degrades Keap1 in a p62-dependent manner, further promoting nuclear transcription of Nrf2 and thus effectively reducing oxidative stress. In addition, based on the three-dimensional eutectic structure, it was confirmed that CA directly targets Keap1 protein by interacting with residues M550 and N532, inducing conformation changes in Keap1 protein. We also found that the CA analog chlorogenic acid (GCA) can bind Keap1. In conclusion, this study elucidates a novel molecular mechanism and structural basis for the protective effects of CA against oxidative damage via the Keap1-Nrf2 pathway.

Pathological vascular remodeling is a hallmark of various vascular diseases. Previous research has established the significance of andrographolide in maintaining gastric vascular homeostasis and its pivotal role in modulating endothelial barrier dysfunction, which leads to pathological vascular remodeling. Potassium dehydroandrographolide succinate (PDA), a derivative of andrographolide, has been clinically utilized in the treatment of inflammatory diseases precipitated by viral infections. This study investigates the potential of PDA in regulating pathological vascular remodeling. The effect of PDA on vascular remodeling was assessed through the complete ligation of the carotid artery in C57BL/6 mice. Experimental approaches, including rat aortic primary smooth muscle cell culture, flow cytometry, bromodeoxyuridine (BrdU) incorporation assay, Boyden chamber cell migration assay, spheroid sprouting assay, and Matrigel-based tube formation assay, were employed to evaluate the influence of PDA on the proliferation and motility of smooth muscle cells (SMCs). Molecular docking simulations and co-immunoprecipitation assays were conducted to examine protein interactions. The results revealed that PDA exacerbates vascular injury-induced pathological remodeling, as evidenced by enhanced neointima formation. PDA treatment significantly increased the proliferation and migration of SMCs. Further mechanistic studies disclosed that PDA upregulated myeloid differentiation factor 88 (MyD88) expression in SMCs and interacted with T-cadherin (CDH13). This interaction augmented proliferation, migration, and extracellular matrix deposition, culminating in pathological vascular remodeling. Our findings underscore the critical role of PDA in the regulation of pathological vascular remodeling, mediated through the MyD88/CDH13 signaling pathway.
Mice ; Rats ; Animals ; Myeloid Differentiation Factor 88/metabolism* ; Vascular Remodeling ; Cell Proliferation ; Vascular System Injuries/pathology* ; Carotid Artery Injuries/pathology* ; Molecular Docking Simulation ; Muscle, Smooth, Vascular ; Cell Movement ; Mice, Inbred C57BL ; Signal Transduction ; Succinates/pharmacology* ; Potassium/pharmacology* ; Cells, Cultured ; Diterpenes ; Cadherins

Aim To investigate the dynamic time-course changes in neuronal cytoskeleton after acute ischemia and reperfusion in rats. Methods Reperfusion was performedin rats by blocking the middle cerebralarteryfor 90 min, then therats wereobserved and collected at different time points. The brain damage wasobserved by Nissl staining,and neurobehavioural function was evaluated with neurological deficit score and forelimb placement test. The cellular changes in the alternations of cytoskeletal elements including microtubule associated protein 2 (MAP2) and neurofilament heavy chain (NF-H) were observed by immunohistochemistry staining and Western blot. Impaired axons, dendrites and cytoskeletal alternations were detected by electron microscope. Results Brain damage and neurobehavioural function were gradually aggravated with the prolongation of reperfusion. Brain damage appeared earlier and more severe in striatum than in cortex. Moreover, decreased MAP2-related and increased NF-H-related immunoreactive intensities were found in the ischemic areas. Impaired cytoskeletal arrangement and reduced dense were indicated. Damaged cytoskeletal components such as microtubules and neurofilament arrangement, decreased axonal filament density, and swelled dendrites were observed after cerebral ischemia reperfusion by ultrastructural observations. Conclusions Different brain regions have diverse tolerance to ischemia-reperfusion injury. Major elements of neuronal cytoskeleton show dynamic responses to ischemia and reperfusion, which may further contribute to brain damage and neurological impairment following MCAO and reperfusion.

AIM: To assess the repeatability and agreement of higher-order aberration obtained by adaptive optics visual simulator(VAO)compared with OPD-Scan Ⅲ.METHODS: A cross-sectional study was conducted from August to September 2023, including a total of 204 patients(204 eyes)with myopia whose right eyes were measured. The examinations were performed by the same skilled examiner using both devices separately. The VAO device was used to measure higher order aberrations of orders 3 to 6 at a pupil diameter of 4.5 mm, while both the VAO and OPD-Scan Ⅲ devices were utilized to measure total higher-order aberration(tHOA), spherical aberration(SA), coma aberration(Coma), and trefoil aberration(Trefoil)of the entire eye at pupil diameters ranging from 3 to 6 mm. Furthermore, the repeatability of whole eye aberration measurements obtained with the VAO device was evaluated and the agreement of the two devices was assessed.RESULTS: The whole-eye higher-order aberrations measured by VAO demonstrated excellent repeatability(0.767≤ICC≤0.941, Sw<0.01 μm, TRT<0.1 μm). There was no statistically significant difference in Coma measured by VAO or OPD-Scan Ⅲ for pupil diameters ranging from 4 to 6 mm(P>0.05), while a statistically significant difference was observed in whole-eye tHOA of other pupil diameters(all P<0.05). The agreement of aberration measurements for each order between VAO and OPD-Scan Ⅲ for 3 mm pupil diameters, SA at 4 and 5 mm pupil diameter and Coma at 4 mm pupil diameter showed a 95% limit of agreement(LoA)<0.1, indicating good agreement; however, poor agreement was found for the remaining aberration measurements at different pupil diameters, with a 95%LoA>0.1, and there were significant differences in higher-order aberrations measured by two devices under a pupil diameter of 3 mm(r=0.218-0.317, P<0.01), 4 mm(r=0.406-0.672, P<0.01), 5 mm(r=0.538-0.839, P<0.01 and r=0.030-0.109, P>0.01)and 6 mm(r=0.369-0.766, P<0.01).CONCLUSION: The VAO demonstrates favorable repeatability when assessing whole-eye higher order aberration under pupil diameters of 3-6 mm. However, there is inadequate agreement and interchangeability in whole-eye higher order aberration at 3-6 mm pupil diameter between VAO and OPD-Scan Ⅲ for clinical purposes.

Near infrared spectroscopy(NIRS)technology combined with chemometrics algorithms has been widely used in quantitative and qualitative analysis of food and medicine.However,traditional chemometrics methods,especially linear classification methods,often yield unsatisfactory results when addressing multi-class classification problems.Convolutional neural network(CNN)is adept at extracting deep-level features from data and suitable for handling non-linear relationships.The modeling performance of CNN depends on the size and diversity of sample,while the collection and preprocessing of NIRS sample data is often time-consuming and labor-intensive.This study proposed a NIRS qualitative analysis method based on data augmentation strategies and CNN.The data augmentation strategy included two steps.Firstly,applying Bootstrap resampling and generative adversarial network(GAN)methods to augment three NIRS datasets(Medicine,coffee and grape).Secondly,combining the original samples(Y)with the Bootstrap augmented samples(B)and GAN augmented samples(G)to obtain three augmented datasets(Y-B,Y-G and Y-B-G).Based on this,a CNN model structure suitable for these datasets was designed,consisting of 2 one-dimensional convolutional layers,1 max-pooling layer,and 1 fully connected layer.The results showed that compared to the optimal models of partial least squares discriminant analysis(PLS-DA),support vector machine(SVM),and back propagation neural network(BP),the CNN model based on Y-B dataset achieved average accuracy improvements of 3.998%,9.364%,and 4.689%for medicine(Binary classification);the CNN model based on the Y-B-G dataset achieved average accuracy improvements of 6.001%,2.004%,and 7.523%for coffee(7-class classification);and the CNN model based on the Y-B dataset achieved average accuracy improvements of 33.408%,51.994%,and 34.378%for grapes(20-class classification).It was evident that the models established based on data augmentation strategies and CNN demonstrated better classification accuracy and generalization performance with different datasets and classification categories.

Aim To investigate the dynamic changes of neuronal cells at different time points following acute cerebral ischemia-reperfusion injury by establishing a model of brain ischemia-reperfusion injury.Methods Thirty male Sprague-Dawley(SD)rats were ran-domly divided into six groups:sham group and cere-bral ischemia-reperfusion injury(IR)groups at differ-ent time points.Focal cerebral ischemia-reperfusion injury model was established using the middle cerebral artery occlusion(MCAO)technique.The Longa sco-ring method was used to assess neurobehavioral scores in rats.After successful model preparation,routine paraffin sections were made,and TUNEL staining and immunohistochemistry staining with NeuN antibody were performed to observe cell apoptosis and neuronal cell survival,respectively.Immunohistochemistry stai-ning was also performed to investigate the changes in glial fibrillary acidic protein(GFAP)as a marker for astrocytes,ionized calcium-binding adapter molecule 1(IBA-1)as a marker for microglia,and CD31 as a marker for endothelial cells at different time points.Results No significant changes were observed in neu-ronal cells of the sham group at different time points.In the cerebral ischemia-reperfusion injury groups,cell apoptosis was activated at IR3h and increased in quan-tity with morphological damage as time progressed.Ne-uN+neurons showed signs of ischemic injury after IR3h,with abnormal cell morphology.From 12 h,Ne-uN+neurons decreased in a time-dependent manner and reached their peak severity at 24 h.GFAP+astro-cytes decreased significantly after IR3h,while poorly labeled GFAP+astrocytes increased at IR 6 h and al-most disappeared in the infarcted area at 24 h and 48 h.The number of IBA-1+microglia-positive cells de-creased at IR3h,and their volume increased at IR6h.Microglial cell death was observed in the infarcted area at IR12h.CD31+endothelial cells around the infarc-ted cortex and striatum increased significantly after IR3h and persisted until 48 h.Conclusions After cerebral ischemia-reperfusion injury,the number of ap-optotic cells increases with the prolongation of time,and NeuN+neurons exhibit the most severe damage at 24 h.GFAP+astrocytes and microglial cells gradually die over time.The number of CD31+endothelial cells increases significantly around the infarcted cortex and striatum after 3 h of reperfusion and persists until 48 h.

This study aims to explore the effect of Xiaoxuming Decoction on synaptic plasticity in rats with acute cerebral ischemia-reperfusion. A rat model of cerebral ischemia-reperfusion injury was established by middle cerebral artery occlusion(MCAO). Rats were randomly assigned into a sham group, a MCAO group, and a Xiaoxuming Decoction(60 g·kg~(-1)·d~(-1)) group. The Longa score was rated to assess the neurological function of rats with cerebral ischemia for 1.5 h and reperfusion for 24 h. The 2,3,5-triphenyltetrazolium chloride(TTC) staining and hematoxylin-eosin(HE) staining were employed to observe the cerebral infarction and the pathological changes of brain tissue after cerebral ischemia, respectively. Transmission electron microscopy was employed to detect the structural changes of neurons and synapses in the ischemic penumbra, and immunofluorescence, Western blot to determine the expression of synaptophysin(SYN), neuronal nuclei(NEUN), and postsynaptic density 95(PSD95) in the ischemic penumbra. The experimental results showed that the modeling increased the Longa score and led to cerebral infarction after 24 h of ischemia-reperfusion. Compared with the model group, Xiaoxuming Decoction intervention significantly decreased the Longa score and reduced the formation of cerebral infarction area. The modeling led to the shrinking and vacuolar changes of nuclei in the brain tissue, disordered cell arrangement, and severe cortical ischemia-reperfusion injury, while the pathological damage in the Xiaoxuming Decoction group was mild. The modeling blurred the synaptic boundaries and broadened the synaptic gap, while such changes were recovered in the Xiaoxuming Decoction group. The modeling decreased the fluorescence intensity of NEUN and SYN, while the intensity in Xiaoxuming Decoction group was significantly higher than that in the model group. The expression of SYN and PSD95 in the ischemic penumbra was down-regulated in the model group, while such down-regulation can be alleviated by Xiaoxuming Decoction. In summary, Xiaoxuming Decoction may improve the synaptic plasticity of ischemic penumbra during acute cerebral ischemia-reperfusion by up-regulating the expression of SYN and PSD95.
Rats ; Animals ; Rats, Sprague-Dawley ; Brain Ischemia/drug therapy* ; Reperfusion Injury/metabolism* ; Infarction, Middle Cerebral Artery ; Neuronal Plasticity ; Reperfusion