With the continuous advancement of deep space exploration missions, maintaining astronaut skin health has become a critical medical issue affecting the safety and effectiveness of long-duration missions. Deep space environmental stressors, including microgravity, ionizing radiation, lunar dust exposure, and microbiome dysbiosis, can synergistically disrupt the skin barrier structure, leading to immune homeostasis imbalance and impaired wound healing. In recent years, research on skin protection in deep space has gradually evolved into a systematic "multi-dimensional integrated protective" framework. From the engineering protection perspective, optimization of multi-layer composite spacesuit structures, the use of hydrogen-rich and boron-containing shielding materials, as well as cabin temperature-humidity regulation and debris-resistant technologies, have greatly enhanced environmental defense capacity. From the biomedical protection perspective, functional hydrogels, antimicrobial dressings, and active compounds derived from traditional Chinese medicine have demonstrated remarkable potential in repairing the skin barrier, modulating immunity, and providing antioxidant defense. Meanwhile, the development of skin microecological interventions and wearable physiological monitoring systems has fostered a trend toward personalized health management. Future research should focus on elucidating the interactive mechanisms among the space environment, skin, and immune barrier, while exploring intelligent monitoring and nanotechnology-based protection strategies. Establishing a predictive and preventive skin health safeguarding system will provide comprehensive medical support for future deep space missions.
Humans ; Astronauts ; Skin/radiation effects* ; Space Flight ; Weightlessness/adverse effects* ; Wound Healing ; Extraterrestrial Environment

OBJECTIVES: To evaluate the photothermal and antibacterial activities of polydopamine-modified phycocyanin nanoparticles (PDA@PC NPs) and their capacity for promoting wound healing. METHODS: PDA@PC NPs were synthesized from phycocyanin (C-PC) and dopamine hydrochloride using a one-pot method. The photothermal activity of the nanoparticles was assessed in vitro by 808 nm laser irradiation, their biocompatibility was evaluated using CCK-8 assay, and their photothermal antibacterial activity by plate colony counting. In adult male BALB/c mice, two symmetrical full-thickness skin wounds (1.0 cm ×1.0 cm) were created on both sides of the spine, and 200 μL of Staphylococcus aureus suspension was inoculated into the wounds. The mice were divided into control group, PDA@PC NPs group, and PDA@PC NPs with laser irradiation group, and wound healing rates and histomorphological changes in the wound tissues were evaluated on days 0, 7 and 14 after modeling. RESULTS: The synthesized PDA@PC NPs exhibited no obvious cytotoxicity up to a concentration of 500 μg/mL and showed strong photothermal and antibacterial activities in response to 808 nm laser irradiation. In the mouse models, the size of the infected skin wounds showed substantial reduction at 7 and 14 days in PDA@PC NPs group and PDA@PC NPs with laser irradiation group, and the mean wound healing rate was faster in the latter group. HE staining and Masson's trichrome staining revealed extensive granulation tissue formation and collagen deposition on the wound surfaces in both of the treatment groups, and these changes were more obvious in the PDA@PC NPs with laser irradiation group. CONCLUSIONS PDA@PC NPs possess excellent photothermal and antibacterial activities and can effectively promote wound healing in mice.
Animals ; Indoles/chemistry* ; Wound Healing/drug effects* ; Mice ; Mice, Inbred BALB C ; Male ; Nanoparticles ; Polymers/chemistry* ; Phycocyanin/chemistry* ; Skin/injuries* ; Staphylococcus aureus/drug effects* ; Anti-Bacterial Agents/pharmacology*

OBJECTIVES: To investigate the mechanism by which chitosan (CS) hydrogel loaded with human umbilical cord mesenchymal stem cell (HUVECs)-derived exosomes (hUCMSC-exos) (Exos@CS-Gel) improves diabetic wound healing. METHODS: hUCMSC-exos were extracted and Exos@CS-Gel was prepared. The effect of Exos@CS-Gel on proliferation and migration of HUVECs were evaluated using scratch wound assay and CCK-8 assay. Diabetic rat models with full-thickness skin wounds established by streptozotocin induction were randomized divided into 4 groups for treatment with Exos@CS-Gel (100 µg hUCMSC-exos dissolved in 100 µL 24% CS hydrogel), hUCMSC-exos (100 µg hUCMSC-exos dissolved in 100 µL PBS), CS hydrogel (100 µL 24% CS hydrogel), or PBS (control group). Wound healing and the therapeutic mechanisms were assessed using immunohistochemistry, HE staining, immunofluorescence, and qRT-PCR. RESULTS: In cultured HUVECs, Exos@CS-Gel treatment significantly promoted cell proliferation and migration. In the rat models of chronic diabetic wounds, the wound healing rate in Exos@CS-Gel group reached 92.7% on day 14, significantly higher than those in hUCMSC-exos group (9.12%), CS hydrogel group (16.28%), and control group (25.98%). Microvessel density and the expression levels of vascular endothelial growth factor and transforming growth factor β-1 were significantly increased in the Exos@CS-Gel group. CONCLUSIONS Exos@CS-Gel promotes survival capacity of hUCMSC-exos in vitro and accelerates diabetic wound healing in rats by promoting angiogenesis and cell proliferation.
Animals ; Wound Healing ; Humans ; Chitosan ; Exosomes ; Mesenchymal Stem Cells/cytology* ; Diabetes Mellitus, Experimental ; Rats ; Umbilical Cord/cytology* ; Hydrogels ; Human Umbilical Vein Endothelial Cells ; Cell Proliferation ; Rats, Sprague-Dawley ; Male

Frostbite is the most common cold injury and is caused by both immediate cold-induced cell death and the gradual development of localized inflammation and tissue ischemia. Delayed healing of frostbite often leads to scar formation, which not only causes psychological distress but also tends to result in the development of secondary malignant tumors. Therefore, a rapid healing method for frostbite wounds is urgently needed. Herein, we used a mouse skin model of frostbite injury to evaluate the recovery process after frostbite. Moreover, single-cell transcriptomics was used to determine the patterns of changes in monocytes, macrophages, epidermal cells, and fibroblasts during frostbite. Most importantly, human-induced pluripotent stem cell (hiPSC)-derived skin organoids combined with gelatin-hydrogel were constructed for the treatment of frostbite. The results showed that skin organoid treatment significantly accelerated wound healing by reducing early inflammation after frostbite and increasing the proportions of epidermal stem cells. Moreover, in the later stage of wound healing, skin organoids reduced the overall proportions of fibroblasts, significantly reduced fibroblast-to-myofibroblast transition by regulating the integrin α5β1-FAK pathway, and remodeled the extracellular matrix (ECM) through degradation and reassembly mechanisms, facilitating the restoration of physiological ECM and reducing the abundance of ECM associated with abnormal scar formation. These results highlight the potential application of organoids for promoting the reversal of frostbite-related injury and the recovery of skin functions. This study provides a new therapeutic alternative for patients suffering from disfigurement and skin dysfunction caused by frostbite.
Animals ; Organoids/metabolism* ; Mice ; Humans ; Wound Healing ; Frostbite/metabolism* ; Skin/pathology* ; Induced Pluripotent Stem Cells/cytology* ; Cicatrix/pathology* ; Fibroblasts/metabolism* ; Disease Models, Animal ; Mice, Inbred C57BL ; Extracellular Matrix/metabolism* ; Male

OBJECTIVES: This study aims to evaluate the clinical effect of low-energy semiconductor laser treatment on the promotion of wound healing after maxillofacial fracture surgery. METHODS: A prospective randomized controlled study was conducted. Patients with maxillofacial fractures who were hospitalized in the Department of Trauma and Plastic Surgery, West China Hospital of Stomatology, Sichuan University, from August 2021 to June 2023 were selected as the study subjects and randomly divided into experimental and control groups. The experimental group was treated with a low-energy semiconductor laser once a day for six consecutive days after daily routine dressing change on the first day after surgery. The control group only underwent routine dressing change treatment and did not receive low-energy semiconductor laser treatment. Wound healing times, wound healing conditions, modified Stony Brook scar evaluation scale (mSBSES) scores, pain indices, and wound infection rates were compared between the two groups. RESULTS: A total of 211 patients were included in this study. A total of 104 and 107 cases comprised the experimental and control groups, respectively. A total of 128 males and 83 females were included. After low-energy semiconductor laser treatment, the facial skin wound healing time of the experimental group was found to be significantly shorter than that of the control group (P<0.05). Moreover, the wound grade A healing rate of the experimental group was higher than that of the control group on the seventh day after surgery (P<0.05). Among postoperative facial skin wound evaluation indices, the mSBSES scores of the experimental group at all observation points were higher than those of the control group (P<0.05), and the scores of the experimental group were higher than those of the control group in terms of wound width reduction, height reduction, color lightening, and incision line loss (P<0.05). In postoperative wound pain evaluation, the pain index of the experimental group after low-energy semiconductor laser treatment was significantly lower than that of the control group (P<0.05). No significant difference in wound infection rates was found between the two groups (P>0.05). CONCLUSIONS For facial skin wounds in maxillofacial fracture surgery, low-energy semiconductor laser treatment can effectively promote wound healing, improve wound healing quality, fade scars, and relieve wound pain.
Humans ; Wound Healing/radiation effects* ; Male ; Female ; Lasers, Semiconductor/therapeutic use* ; Prospective Studies ; Adult ; Middle Aged ; Low-Level Light Therapy ; Maxillofacial Injuries/surgery* ; Young Adult

OBJECTIVES: To study the clinical effect of the L-shape technique combined with concentrated growth factor on the horizontal bone defects of maxillary anterior teeth. METHODS: Twenty-five implants from 25 patients who underwent single maxillary anterior tooth implantation with simultaneous bone grafting were selected as the study subjects. Based on the bone grafting techniques, the patients were divided into a test group (L-shaped technique with guided bone regeneration combined with concentrated growth factor, 11 cases) and a control group (traditional guided bone regeneration combined with concentrated growth factor, 14 cases). The early discomfort and wound healing conditions in the two groups at two weeks after surgery were compared. The horizontal bone thickness, vertical bone thickness, and grayscale values in the augmentation area were measured immediately postsurgery and six months after surgery. Implant stability, hard tissue resorption within six months, and grayscale values were compared between the two groups. RESULTS: Differences in early discomfort, wound healing, implant stability, and grayscale values between the two groups were not statistically significant (P>0.05). Vertical bone thickness in the test group was significantly better than that in the control group at six months after surgery (P<0.05). The variation in horizontal bone thickness in the test group was significantly higher than that in the control group (P<0.05). CONCLUSIONS The application of the L-shape technique with concentrated growth factor for horizontal bone defects in the anterior maxillary area yielded satisfactory short-term results in terms of bone augmentation, early discomfort, wound healing, and implant stability at six months after surgery.
Humans ; Maxilla/diagnostic imaging* ; Intercellular Signaling Peptides and Proteins/therapeutic use* ; Wound Healing ; Bone Transplantation/methods* ; Dental Implantation, Endosseous/methods* ; Bone Regeneration ; Male ; Female ; Adult ; Dental Implants, Single-Tooth ; Middle Aged

OBJECTIVES: To evaluate the osteogenic efficacy of three-dimensional printing individualized titanium mesh (3D-PITM) as a scaffold material in guided bone regeneration (GBR). METHODS: 1) Patients undergoing GBR for alveolar bone defects were enrolled as study subjects, and postoperative healing complications were recorded. 2) Postoperative cone beam computed tomography (CBCT) scans acquired at least 6 months post-surgery were used to calculate the percentage of actual bone formation volume. 3) Alveolar bone specimens were collected during the first-stage implant surgery for histomorphometric analysis. This analysis quantitatively measured the proportions of newly formed bone and newly formed unmineralized bone within the specimens. Specimens were categorized into three groups based on healing complications (good healing group, wound dehiscence group, 3D-PITM exposure group) to compare differences in the proportions of newly formed bone and newly formed unmineralized bone. RESULTS: 1) Twelve patients were included. Guided bone regeneration failed in one patient, and 3D-PITM exposure occurred in three patients (exposure rate: 25%). 2) The mean percentage of actual bone formation volume in the 11 successful guided bone regeneration cases was 95.23%±28.85%. 3) Histomorphometric analysis revealed that newly formed bone constituted 40.35% of the alveolar bone specimens, with newly formed unmineralized bone accounting for 13.84% of the newly formed bone. Intergroup comparisons showed no statistically significant differences (P>0.05) in the proportions of newly formed bone or newly formed unmineralized bone between the good healing group and the wound dehiscence group or the 3D-PITM exposure group. CONCLUSIONS 3D-PITM enables effective bone augmentation. Radiographic assessment demonstrated favorable bone formation volume, while histological analysis confirmed substantial formation of newly formed mineralized bone within the surgical site.
Humans ; Printing, Three-Dimensional ; Titanium ; Cone-Beam Computed Tomography ; Bone Regeneration ; Osteogenesis ; Surgical Mesh ; Tissue Scaffolds ; Alveolar Process/surgery* ; Adult ; Male ; Middle Aged ; Female ; Wound Healing ; Guided Tissue Regeneration, Periodontal/methods* ; Alveolar Bone Loss/surgery*

OBJECTIVES: To compare the clinical effects of concentrated growth factor (CGF) membrane and Bio-Gide ^® collagen membrane, combined with Bio-Oss ^® sticky bone respectively in alveolar ridge preservation (ARP) of maxillary anterior teeth. METHODS: Thirty patients who needed alveolar ridge preservation after maxillary anterior tooth extraction were selected and randomly assigned to the Bio-Gide group and the CGF group. In both groups, the extraction sockets were tightly filled with the Bio-Oss^® sticky bone. In the Bio-Gide group used Bio-Gide^® collagen membrane to cover the upper edge of the Bio-Oss^® sticky bone and closed the wound. The CGF group, the CGF membrane was covered on the upper edge of the Bio-Oss^® sticky bone and the wound was closed. The soft tissue wound healing status at 10 days after ARP, the changes in alveolar ridge height and width immediately after ARP and at 6 months after ARP, and the doctor-patient satisfaction at 6 months after ARP were compared and evaluated between the two groups. RESULTS: At 6 months after ARP, there was no statistically significant difference in the changes of alveolar bone width and height between the two groups (P>0.05). However, the CGF group showed better performance in soft tissue healing after ARP and doctor-patient satisfaction, and the differences were statistically significant (P<0.05). CONCLUSIONS Compared with the Bio-Gide^® collagen membrane, the combined application of CGF membrane and Bio-Oss^® sticky bone can lead to better soft tissue healing after ARP of maxillary anterior teeth and higher doctor-patient satisfaction, showing obvious advantages in ARP of maxillary anterior teeth.
Humans ; Maxilla/surgery* ; Tooth Extraction ; Alveolar Process/surgery* ; Membranes, Artificial ; Alveolar Ridge Augmentation/methods* ; Intercellular Signaling Peptides and Proteins/therapeutic use* ; Minerals/therapeutic use* ; Collagen ; Wound Healing ; Tooth Socket/surgery* ; Bone Substitutes/therapeutic use* ; Male ; Female ; Middle Aged ; Alveolar Bone Loss/prevention & control* ; Adult

Growth factors (GFs) are a class of peptides that facilitate cell growth by binding to specific receptors on the cell membrane. With unique properties, GFs are widely applied in the repair of injured tissue. To address the limitations associated with natural peptide-based GFs and recombinant GFs, researchers have developed diverse GF mimetics. This article offers a comprehensive review on common types of GFs and their applications in tissue repair and summarizes the features of GF mimetics currently under development. The aim is to provide valuable references for promoting the application of GFs in regenerative medicine.
Intercellular Signaling Peptides and Proteins/therapeutic use* ; Humans ; Tissue Engineering/methods* ; Regenerative Medicine/methods* ; Animals ; Wound Healing/drug effects* ; Biomimetic Materials

Diabetic chronic wounds are characterized by difficult healing, recurrent progression, and high rates of disability and mortality, which make their clinical treatment a medical challenge urgent to be addressed. However, the complex local microenvironment conditions of chronic wounds, such as high protease activity and persistent inflammatory responses, result in low bioavailability of exogenous cytokines (e.g., chemokine CXCL12) at the wound site, limiting their clinical application. In this study, we utilized Lactobacillus plantarum WCFS1 as the chassis to develop an efficient CXCL12 delivery system based on synthetic biology. Subsequently, we evaluated the role of the engineered probiotic strain in promoting the chronic wound healing in diabetic mice. Firstly, we fused the endogenous secretion signal peptide lp_3050 (SP_{lp_3050}) of L. plantarum WCFS1 and the commonly used secretion signal peptide usp45 (SP_usp45) of lactic acid bacteria with the reporter gene gusA and inserted them into the pTRK892-P_32(pgm) plasmid by molecular cloning. Then, we prepared the engineered strains and characterized the efficacy of the two signal peptides in driving the secretion of GusA. The results showed that SP_{lp_3050} efficiently drove the secretion of GusA in L. plantarum WCFS1, increasing the activity of GusA in the culture supernatant by nearly five times compared with that of SP_{lp_3050}. Further, we fused SP_{lp_3050} and codon-optimized CXCL12 gene to construct an engineered probiotic strain Lpw-CXCL12 for CXCL12 delivery. The results demonstrated that the content of CXCL12 in the culture supernatant reached (13.40±0.20) μg/mL. Finally, we found that the engineered probiotic strain Lpw-CXCL12 accelerated chronic wound healing in a diabetic mouse model. In conclusion, these results support an engineered probiotic strain in promoting diabetic chronic wound healing, providing a new strategy and technological foundation for the management of diabetic chronic wounds in the future.
Probiotics ; Animals ; Chemokine CXCL12/biosynthesis* ; Mice ; Wound Healing ; Lactobacillus plantarum/metabolism* ; Diabetes Mellitus, Experimental/complications* ; Male