Unraveling the Mechanisms Involved in the Beneficial Effects of Magnesium Treatment on Skin Wound Healing.

The skin wound healing process consists of hemostatic, inflammatory, proliferative, and maturation phases, with a complex cellular response by multiple cell types in the epidermis, dermis, and immune system. Magnesium is a mineral essential for life, and although magnesium treatment promotes cutaneous wound healing, the molecular mechanism and timing of action of the healing process are unknown. This study, using human epidermal-derived HaCaT cells and human normal epidermal keratinocyte cells, was performed to investigate the mechanism involved in the effect of magnesium on wound healing. The expression levels of epidermal differentiation-promoting factors were reduced by MgCl2, suggesting an inhibitory effect on epidermal differentiation in the remodeling stage of the late wound healing process. On the other hand, MgCl2 treatment increased the expression of matrix metalloproteinase-7 (MMP7), a cell migration-promoting factor, and enhanced cell migration via the MEK/ERK pathway activation. The enhancement of cell migration by MgCl2 was inhibited by MMP7 knockdown, suggesting that MgCl2 enhances cell migration which is mediated by increased MMP7 expression. Our results revealed that MgCl2 inhibits epidermal differentiation but promotes cell migration, suggesting that applying magnesium to the early wound healing process could be beneficial.

Experimental Approaches to Scar Modeling through Mechanical Skin Damage and Chemical Burn in Sprague Dawley Rats.

Creating of a scar model in laboratory animals is the most acceptable option for the preclinical search of scar treatment. However, due to high skin regeneration rate in laboratory rodents, creating an optimal animal model of scar formation is a challenge. Here we describe five methods for modeling a scar tissue in rats that we have tested. These methods allowed achieving different histopathological features and different stages of skin scar formation.

Improvement of skin wound healing by giant salamander skin mucus gel wrapped with bone marrow mesenchymal stem cells via affecting integrin family molecules.

BACKGROUND: Traditional bandages, gauze, and cotton balls are increasingly insufficient for addressing complex war injuries characterized by severe bleeding and diverse wound conditions. The giant salamander, a species of high medical value, secretes a unique mucus when stimulated, which has potential applications in wound care. MATERIALS: Giant salamander skin mucus gel dressing wrapped with bone marrow mesenchymal stem cells (BMSCs-GSSM-gel) was prepared and validated. Skin wound injury of rabbit and mouse models were established. Hematoxylin and Eosin, Masson's trichrome, and Sirius red staining were performed. The platelet aggregation rate and coagulation items were measured. Transcriptome sequencing was performed to find potential differential expression genes. RESULTS: Preparation and characterization of BMSCs-GSSM-gel were performed, and BMSCs-GSSM-gel particles with a diameter of about 200 nm were obtained. BMSCs-GSSM-gel accelerated wound healing in both rabbit and mouse models. BMSCs-GSSM-gel significantly promoted hemostasis via increasing platelet aggregation rate and fibrinogen, but decreasing activated partial thromboplastin time, thrombin time, and prothrombin time. BMSCs-GSSM-gel treatment significantly impacted several genes associated with cell adhesion, inflammatory response, collagen-containing extracellular matrix, and the positive regulation of cell migration based on Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Integrin Subunit Beta 4 (ITGB4), Integrin Subunit Alpha 3 (ITGA3), and Laminin Subunit Beta 3 (LAMB3) might be involved in the wound healing process by BMSCs-GSSM-gel. CONCLUSIONS: We proved the BMSCs-GSSM-gel greatly improved the skin wound healing, and it might play a crucial role in the application fields of skin damage repair.

Exploring the therapeutic potential of allogeneic amniotic membrane for quality wound healing in rabbit model.

BACKGROUND: The amniotic membrane (AM) has shown immense potential in repairing wounds due to its great regenerative qualities. Although the role of AM as a biological scaffold in repairing wounds has been studied well, the tissue regenerative potential of AM-derived mesenchymal stem cells (MSCs) and conditioned media (CM) derived from it remains to be discovered as of now. Here, we examined the wound healing abilities of fresh and frozen thawed rabbit AM (rAM) along with the MSCs and their lyophilised CM in rabbits challenged with skin wounds. METHODS: To elucidate the role of rAM-MSCs and its CM in repairing the wound, we isolated it from the freshly derived placenta and characterised their differentiation potential by performing an in vitro tri-lineage differentiation assay besides other standard confirmations. We compared the wound repair capacities of rAM-MSCs and lyophilised CM with the fresh and cryopreserved AM at different timelines by applying them to excision wounds created in rabbits. RESULTS: By monitoring wound contractions and tissue histology of wounded skin at different time points after the application, we observed that rAM-MSCs and rAM-MSC-derived CM significantly promoted wound closure compared to the control group. We also observed that the wound closure capacity of rAM-MSCs and rAM-MSC-derived CM is as efficient as fresh and cryopreserved rAM. CONCLUSION: Our findings suggest that rAM-MSCs and rAM-MSC derived CM can be effectively used to treat skin wounds in animals and correctly delivered to the damaged tissue using AM as a bioscaffold, either fresh or frozen.

Cumin (Cuminum cyminum L.) seeds accelerates wound healing in rats: Possible molecular mechanisms.

Wound healing is a complex, intricate, and dynamic process that requires effective therapeutic management. The current study evaluates the wound healing potentials of methanolic extract of Cuminum cyminum L. seeds (CCS) in rats. Sprague Dawley (24) rats were distributed into four cages, wounds produced on the back of the neck, and received two daily topical treatments for 14 days: A, rats received normal saline; B, wounded rats treated with intrasite gel; C and D, rats received 0.2 mL of 250 and 500 mg/kg of CCS, respectively. After that, wound area and closure percentage were evaluated, and wound tissues were dissected for histopathological, immunohistochemical, and biochemical examinations. Acute toxicity trials of methanolic extract of CCS showed the absence of any physiological changes or mortality in rats. CCS application caused a significant reduction in wound size and a statistically elevated percentage of wound contraction than those of vehicle rats. CCS treatment caused significant up-regulation of collagen fiber, fibroblasts, and fewer inflammatory cells (inflammation) in granulation tissues. TGF-ß1 (angiogenetic factor) was significantly more expressed in CCS-treated rats in comparison to normal saline-treated rats; therefore, more fibroblasts transformed into myofibroblasts (angiogenesis). CCS-treated rats showed remarkable antioxidant potentials (higher SOD and CAT enzymes) and decreased MDA (lipid peroxidation) levels in their wound tissue homogenates. Hydroxyproline amino acid (collagen) was significantly up-regulated by CCS treatment, which is commonly related to faster wound closure area. The outcomes suggest CCS as a viable new source of pharmaceuticals for wound treatment.

Subminute thermal damage to cell types present in the skin.

INTRODUCTION: Psoriasis is characterized by an increase in the proliferation of keratinocytes and nerve fiber activity, contributing to the typical skin lesions. Pulsed Dye Laser (PDL) treatment is effective for the treatment of psoriatic lesions but its mechanism remains unclear. One hypothesis is that PDL causes thermal damage by the diffusion of heat to neighboring structures in lesional skin. There is limited information on the thermal sensitivity of these neighboring skin cells when exposed to hyperthermia for durations lasting less than a minute. Our study aimed to investigate the cell-specific responses to heat using sub-minute exposure times and moderate to ablative hyperthermia. MATERIALS AND METHODS: Cultured human endothelial cells, smooth muscle cells, neuronal cells, and keratinocytes were exposed to various time (2-20 sec) and temperature (45-70 °C) combinations. Cell viability was assessed by measuring intracellular ATP content 24 h after thermal exposure and this data was used to calculate fit parameters for the Arrhenius model and CEM43 calculations. RESULTS: Our results show significant differences in cell survival between cell types (p < 0.0001). Especially within the range of 50-60 °C, survival of neuronal cells and keratinocytes was significantly less than that of endothelial and smooth muscle cells. No statistically significant difference was found in the lethal dose (LT50) of thermal energy between neuronal cells and keratinocytes. However, CEM43 calculations showed significant differences between all four cell types. CONCLUSION: The results imply that there is a cell-type-dependent sensitivity to thermal damage which suggests that neuronal cells and keratinocytes are particularly susceptible to diffusing heat from laser treatment. Damage to these cells may aid in modulating the neuro-inflammatory pathways in psoriasis. These data provide insight into the potential mechanisms of PDL therapy for psoriasis and advance our understanding of how thermal effects may play a role in its effectiveness.

Investigating the Relevance of Cyclic Adenosine Monophosphate Response Element-Binding Protein to the Wound Healing Process: An In Vivo Study Using Photobiomodulation Treatment.

Monitoring inflammatory cytokines is crucial for assessing healing process and photobiomodulation (PBM) enhances wound healing. Meanwhile, cAMP response element-binding protein (CREB) is a regulator of cellular metabolism and proliferation. This study explored potential links between inflammatory cytokines and the activity of CREB in PBM-treated wounds. A total of 48 seven-week-old male SD rats were divided into four groups (wound location, skin or oral; treatment method, natural healing or PBM treatment). Wounds with a 6 mm diameter round shape were treated five times with an 808 nm laser every other day (total 60 J). The wound area was measured with a caliper and calculated using the elliptical formula. Histological analysis assessed the epidermal regeneration and collagen expression of skin and oral tissue with H&E and Masson's trichrome staining. Pro-inflammatory (TNF-α) and anti-inflammatory (TGF-ß) cytokines were quantified by RT-PCR. The ratio of phosphorylated CREB (p-CREB) to unphosphorylated CREB was identified through Western blot. PBM treatment significantly reduced the size of the wounds on day 3 and day 7, particularly in the skin wound group (p < 0.05 on day 3, p < 0.001 on day 7). The density of collagen expression was significantly higher in the PBM treatment group (in skin wound, p < 0.05 on day 3, p < 0.001 on day 7, and p < 0.05 on day 14; in oral wound, p < 0.01 on day 7). The TGF-ß/TNF-α ratio and the p-CREB/CREB ratio showed a parallel trend during wound healing. Our findings suggested that the CREB has potential as a meaningful marker to track the wound healing process.

[Detection of some markers of the early phase of the inflammatory and reparative process in mechanical skin injuries]. / Vyyavlenie nekotorykh markerov rannei fazy vospalitel'no-reparativnogo protsessa pri mekhanicheskikh povrezhdeniyakh kozhi.

OBJECTIVE: To examine the applicability of IHC staining method: with TGF-ß1 antibodies (serial examination, statistically processed results) and with mast cell tryptase antibodies for injuries vitality determination. MATERIAL AND METHODS: 261 skin autopsy samples with mechanical injuries from 29 persons were divided to 3 groups (87 in each group): vital injuries, postmortal injuries, control non-injured samples. A routine histological examination using standard H&E stain and IHC both with TGF-ß1 and mast cells tryptase antibodies was performed. RESULTS AND CONCLUSION: The positive TGF-ß1 staining (score 2-3) was found in keratinocytes in vitally injured skin and the negative or weak one (score 0-1) was found in control postmortally injured and non-injured samples. Additionally, dermal TGF-ß1 expression was found in some vitally injured skin samples. The difference between vitally injured skin and control samples was statistically significant (p<0.05). No significant difference of dermal mast cells density in groups 1, 2, 3 was found.

Iatrogenic skin injuries in infants admitted to neonatal intensive care units: An investigation in 22 Chinese units.

OBJECTIVE: To investigate the incidence of iatrogenic skin injuries in neonates across 22 neonatal intensive care units (NICUs) in China. DESIGN: Prospective study. SETTING: 22 NICUs in China. PATIENTS: Infants admitted to NICU. INTERVENTIONS: None. MEASUREMENTS: The "Iatrogenic Skin Injuries Data Collection Form of infants" were used to collect the data during hospitalization. MAIN RESULTS: A total of 8126 neonates who were hospitalized in 22 tertiary hospitals across 15 provinces, cities, and autonomous regions of China between December 1, 2019 and January 31, 2020 were analyzed. Five hundred and twenty-one infants had iatrogenic skin injuries, including 250 with diaper dermatitis (47.98%), 70 with physicochemical factor-related skin lesions (PCFRSIs) (13.44%), 81 with medical device-related pressure injuries (MDRPIs) (15.55%), and 69 with medical adhesive-related skin injuries (MARSIs) (13.24%), accounting for 91% of the total number of iatrogenic injuries. Among these, diaper dermatitis was closely related to the skin and feeding status. Furthermore, the risk was higher among neonates who had skin damage upon admission or were already fully fed orally. The influencing factors of MDRPIs and MARSIs were similar. They were negatively associated with gestational age and birth weight, and were closely related to the presence of various tubes. CONCLUSIONS: Diaper dermatitis, PCFRSIs, MDRPIs, and MARSIs were the four common types of iatrogenic skin injuries in newborns. The various types of iatrogenic skin injuries were influenced by varying factors. Specialized nursing measurements can reduce the likelihood of these injuries.

3D skin bioprinting as promising therapeutic strategy for radiation-associated skin injuries.

Both cutaneous radiation injury and radiation combined injury (RCI) could have serious skin traumas, which are collectively referred to as radiation-associated skin injuries in this paper. These two types of skin injuries require special managements of wounds, and the therapeutic effects still need to be further improved. Cutaneous radiation injuries are common in both radiotherapy patients and victims of radioactive source accidents, which could lead to skin necrosis and ulcers in serious conditions. At present, there are still many challenges in management of cutaneous radiation injuries including early diagnosis, lesion assessment, and treatment prognosis. Radiation combined injuries are special and important issues in severe nuclear accidents, which often accompanied by serious skin traumas. Mass victims of RCI would be the focus of public health concern. Three-dimensional (3D) bioprinting, as a versatile and favourable technique, offers effective approaches to fabricate biomimetic architectures with bioactivity, which provides potentials for resolve the challenges in treating radiation-associated skin injuries. Combining with the cutting-edge advances in 3D skin bioprinting, the authors analyse the damage characteristics of skin wounds in both cutaneous radiation injury and RCI and look forward to the potential value of 3D skin bioprinting for the treatments of radiation-associated skin injuries.

CD80 on skin stem cells promotes local expansion of regulatory T cells upon injury to orchestrate repair within an inflammatory environment.

Following tissue damage, epithelial stem cells (SCs) are mobilized to enter the wound, where they confront harsh inflammatory environments that can impede their ability to repair the injury. Here, we investigated the mechanisms that protect skin SCs within this inflammatory environment. Characterization of gene expression profiles of hair follicle SCs (HFSCs) that migrated into the wound site revealed activation of an immune-modulatory program, including expression of CD80, major histocompatibility complex class II (MHCII), and CXC motif chemokine ligand 5 (CXCL5). Deletion of CD80 in HFSCs impaired re-epithelialization, reduced accumulation of peripherally generated Treg (pTreg) cells, and increased infiltration of neutrophils in wounded skin. Importantly, similar wound healing defects were also observed in mice lacking pTreg cells. Our findings suggest that upon skin injury, HFSCs establish a temporary protective network by promoting local expansion of Treg cells, thereby enabling re-epithelialization while still kindling inflammation outside this niche until the barrier is restored.

Successful Management of Impending Skin Necrosis After a Posterolateral Knee Dislocation.

Incarcerated medial soft tissue after posterolateral knee dislocations has been described, but limited information pertaining to the etiology and management of cutaneous injuries from incarceration exists. We present the case of a 64-year-old man, where reduction of a posterolateral knee dislocation resulted in incarceration of medial ligamentous structures and impending skin necrosis. The patient avoided full-thickness skin necrosis, which could have complicated treatment options. Careful consideration of the soft-tissue envelope of the knee for preventing additional skin injury in the perioperative period should be considered to potentially avert additional necrosis in patients with a 'pucker' sign after knee dislocations.

[Effects of applying human umbilical cord mesenchymal stem cell exosomes through different pathways to treat full-thickness skin defect wounds in mice].

Objective: To investigate the effects of human umbilical cord mesenchymal stem cell (hUCMSC) exosomes in the treatment of full-thickness skin defect wounds in mice through local wound application, subcutaneous injection at the wound margin, and tail vein injection, and to explore the optimal administration route of hUCMSC exosomes for wound treatment. Methods: This study was an experimental study. hUCMSC exosomes were extracted from the discarded umbilical cord tissue of three normal delivery women aged 25-35 years in the Department of Obstetrics and Gynecology of Baogang Hospital of Inner Mongolia and successfully identified. Totally 120 male BALB/c mice aged 6-8 weeks were selected, and full-thickness skin defect wounds were prepared on the back of them. According to the random number table, the injured mice were divided into control group (without drug administration), local wound application group, wound margin subcutaneous injection group, and tail vein injection group (with 30 mice in each group). Mice in the latter three groups were given 0.2 mL phosphate buffer solution containing 200 µg hUCMSC exosomes by local wound application, subcutaneous injection at the wound margin, and tail vein injection, respectively. On post injury day (PID) 7, 14, and 21, the general condition of the wound was observed, and the wound healing rate was calculated; the wound tissue was collected, the pathological changes and collagen fibers were observed respectively by hematoxylin-eosin staining and Masson staining, the number of new microvessels was observed by CD31 immunohistochemical staining, and the content of tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) was detected by enzyme-linked immunosorbent assay. The sample number was 10 in each group at each time point. Results: On PID 7, 14, and 21, the wounds of mice in the 4 groups all healed gradually, and the wound healing of the mice in wound margin subcutaneous injection group was the best; the wound healing rates of mice in the three administration groups were significantly higher than those in control group (P<0.05), the wound healing rates of mice in wound margin subcutaneous injection group and tail vein injection group were significantly higher than those in local wound application group (P<0.05), and the wound healing rates of mice in wound margin subcutaneous injection group were significantly higher than those in tail vein injection group (P<0.05). On PID 7, 14, and 21, the growth and epithelialization speed of the wound tissue of mice in the three administration groups were significantly accelerated, and the collagen fibers in the wounds of mice in the three administration groups were larger in number and more neatly arranged in comparison with the control group. On PID 7, 14, and 21, under every 200-fold visual field, the number of new microvessels in the wound tissue of mice in local wound application group was 24.1±2.5, 50.7±4.1, and 44.2±2.3, respectively, the number of new microvessels in the wound tissue of mice in wound margin subcutaneous injection group was 32.2±2.9, 67.5±4.9, and 53.6±3.7, respectively, and the number of new microvessels in the wound tissue of mice in tail vein injection group was 27.8±2.4, 59.1±3.7, and 49.6±2.6, respectively, which was significantly more than 20.6±1.7, 46.7±3.4, and 40.9±2.8 in control group (P<0.05); the number of new microvessels in the wound tissue of mice in wound margin subcutaneous injection group and tail vein injection group was significantly more than that in local wound application group (P<0.05); the number of new microvessels in the wound tissue of mice in wound margin subcutaneous injection group was significantly more than that in tail vein injection group (P<0.05). On PID 7, 14, and 21, the content of TNF-α and IL-6 in the wound tissue of mice in the three administration groups was significantly less than that in control group (P<0.05), the content of TNF-α and IL-6 in the wound tissue of mice in wound margin subcutaneous injection group and tail vein injection group was significantly less than that in local wound application group (P<0.05), and the content of TNF-α and IL-6 in the wound tissue of mice in wound margin subcutaneous injection group was significantly less than that in tail vein injection group (P<0.05). Conclusions: Local wound application, subcutaneous injection at the wound margin, and tail vein injection of hUCMSC exosomes can all promote the wound healing of full-thickness skin defects in mice through alleviating excessive inflammatory response and promoting angiogenesis. Among them, subcutaneous injection at the wound margin has a better therapeutic effect, indicating subcutaneous injection at the wound margin is the optimal administration route for hUCMSC exosomes in wound treatment.

[Effects of gelatin methacrylate anhydride hydrogel loaded with small extracellular vesicles derived from human umbilical cord mesenchymal stem cells in the treatment of full-thickness skin defect wounds in mice].

Objective: To investigate the effects of gelatin methacrylate anhydride (GelMA) hydrogel loaded with small extracellular vesicles derived from human umbilical cord mesenchymal stem cells (hUCMSCs-sEVs) in the treatment of full-thickness skin defect wounds in mice. Methods: This study was an experimental study. hUCMSCs-sEVs were extracted by ultracentrifugation, their morphology was observed through transmission electron microscope, and the expression of CD9, CD63, tumor susceptibility gene 101 (TSG101), and calnexin was detected by Western blotting. The human umbilical vein endothelial cells (HUVECs), the 3rd and 4th passages of human epidermal keratinocytes (HEKs) and human dermal fibroblasts (HDFs) were all divided into blank control group (routinely cultured) and hUCMSC-sEV group (cultured with the cell supernatant containing hUCMSCs-sEVs). The cell scratch test was performed and the cell migration rates at 6, 12, and 24 h after scratching were calculated, the cell Transwell assay was performed and the number of migration cells at 12 h after culture was calculated, and the proportion of proliferating cells was detected by 5-acetylidene-2'-deoxyuridine and Hoechst staining at 24 h after culture, with sample numbers being all 3. The simple GelMA hydrogel and the GelMA hydrogel loaded with hUCMSCs-sEVs (hereinafter referred to as hUCMSC-sEV/GelMA hydrogel) were prepared. Then the micromorphology of 2 kinds of hydrogels was observed under scanning electron microscope, the distribution of hUCMSCs-sEVs was observed by laser scanning confocal microscope, and the cumulative release rates of hUCMSCs-sEVs at 0 (immediately), 2, 4, 6, 8, 10, and 12 d after soaking hUCMSC-sEV/GelMA hydrogel in phosphate buffer solution (PBS) were measured and calculated by protein colorimetric quantification (n=3). Twenty-four 6-week-old male C57BL/6J mice were divided into PBS group, hUCMSC-sEV alone group, GelMA hydrogel alone group, and hUCMSC-sEV/GelMA hydrogel group according to the random number table, with 6 mice in each group, and after the full-thickness skin defect wounds on the back of mice in each group were produced, the wounds were performed with PBS injection, hUCMSC-sEV suspenson injection, simple GelMA coverage, and hUCMSC-sEV/GelMA hydrogel coverage, respectively. Wound healing was observed on post injury day (PID) 0 (immediately), 4, 8, and 12, and the wound healing rates on PID 4, 8, and 12 were calculated, and the wound tissue was collected on PID 12 for hematoxylin-eosin staining to observe the structure of new tissue, with sample numbers being both 6. Results: The extracted hUCMSCs-sEVs showed a cup-shaped structure and expressed CD9, CD63, and TSG101, but barely expressed calnexin. At 6, 12, and 24 h after scratching, the migration rates of HEKs (with t values of 25.94, 20.98, and 20.04, respectively), HDFs (with t values of 3.18, 5.68, and 4.28, respectively), and HUVECs (with t values of 4.32, 19.33, and 4.00, respectively) in hUCMSC-sEV group were significantly higher than those in blank control group (P<0.05). At 12 h after culture, the numbers of migrated HEKs, HDFs, and HUVECs in hUCMSC-sEV group were 550±23, 235±9, and 856±35, respectively, which were significantly higher than 188±14, 97±6, and 370±32 in blank control group (with t values of 22.95, 23.13, and 17.84, respectively, P<0.05). At 24 h after culture, the proportions of proliferating cells of HEKs, HDFs, and HUVECs in hUCMSC-sEV group were significantly higher than those in blank control group (with t values of 22.00, 13.82, and 32.32, respectively, P<0.05). The inside of simple GelMA hydrogel showed a loose and porous sponge-like structure, and hUCMSCs-sEVs was not observed in it. The hUCMSC-sEV/GelMA hydrogel had the same sponge-like structure, and hUCMSCs-sEVs were uniformly distributed in clumps. The cumulative release rate curve of hUCMSCs-sEVs from hUCMSC-sEV/GelMA hydrogel tended to plateau at 2 d after soaking, and the cumulative release rate of hUCMSCs-sEVs was (59.2±1.8)% at 12 d after soaking. From PID 0 to 12, the wound areas of mice in the 4 groups gradually decreased. On PID 4, 8, and 12, the wound healing rates of mice in hUCMSC-sEV/GelMA hydrogel group were significantly higher than those in the other 3 groups (P<0.05); the wound healing rates of mice in GelMA hydrogel alone group and hUCMSC-sEV alone group were significantly higher than those in PBS group (P<0.05). On PID 8 and 12, the wound healing rates of mice in hUCMSC-sEV alone group were significantly higher than those in GelMA hydrogel alone group (P<0.05). On PID 12, the wounds of mice in hUCMSC-sEV/GelMA hydrogel group showed the best wound epithelization, loose and orderly arrangement of dermal collagen, and the least number of inflammatory cells, while the dense arrangement of dermal collagen and varying degrees of inflammatory cell infiltration were observed in the wounds of mice in the other 3 groups. Conclusions: hUCMSCs-sEVs can promote the migration and proliferation of HEKs, HDFs, and HUVECs which are related to skin wound healing, and slowly release in GelMA hydrogel. The hUCMSC-sEV/GelMA hydrogel as a wound dressing can significantly improve the healing speed of full-thickness skin defect wounds in mice.

[Clinical effects of early rehabilitation treatment after repair surgery of skin and soft tissue defects accompanied by extensor tendon injury on the back of hand].

Objective: To explore the clinical effects of early rehabilitation treatment after repair surgery of skin and soft tissue defects accompanied by extensor tendon injury on the back of hand. Methods: This study was a retrospective non-randomized controlled study. From February 2015 to February 2023, 24 patients (15 males and 9 females, aged 12-55 years) with skin and soft tissue defects accompanied by extensor tendon injury on the back of hand, who met the inclusion criteria and were repaired with flap transplantation and tendon grafting or tendon anastomosis, were admitted to the First Affiliated Hospital of Air Force Medical University. According to different intervention time for postoperative rehabilitation treatment of patients, the patients were divided into conventional rehabilitation group and early rehabilitation group, with 12 cases in each group. Patients in early rehabilitation group received rehabilitation treatment immediately after surgery under the rehabilitation guidance of specialized rehabilitation physicians based on the characteristics of different postoperative periods. Patients in conventional rehabilitation group began rehabilitation treatment from the third week after surgery, and their rehabilitation treatment was the same as that of patients in early rehabilitation group from the second week after surgery. The patients in 2 groups were treated in the hospital until the sixth week after surgery. The occurrence of flap vascular crisis and tendon rupture were observed within 6 weeks after surgery. After 6 weeks of surgery, the manual muscle test was used to measure the pinching force between the index finger and thumb, lateral pinching force, three-point pinching force, and grip force of the affected hand; the total action motion method was used to evaluate the finger joint range of motion of the affected hand, and the excellent and good ratio was calculated; the Carroll upper extremity function test was used to score and rate the function of the affected hand. Results: Within 6 weeks after surgery, only 1 patient in conventional rehabilitation group suffered from venous crisis, and the flap survived after the second surgical exploration and anastomosis of blood vessels; there was no occurrence of tendon rupture in patients of 2 groups. After 6 weeks of surgery, there were no statistically significant differences in pinching force between the index finger and thumb, lateral pinching force, three-point pinching force, or grip force of the affected hand between the two groups of patients (P>0.05); the excellent and good ratio of the finger joint range of motion of the affected hand of patients in early rehabilitation group was 11/12, which was higher than 7/12 in conventional rehabilitation group, but there was no statistically significant difference (P>0.05); the affected hand function score of patients in early rehabilitation group was 90±6, which was significantly higher than 83±8 in conventional rehabilitation group (t=2.41, P<0.05); the function rating of the affected hand of patients in early rehabilitation group was obviously better than that in conventional rehabilitation group (Z=2.04, P<0.05). Conclusions: Early rehabilitation treatment for patients with skin and soft tissue defects accompanied by extensor tendon injury on the back of hand after repair surgery can improve hand function, but it would not increase surgery related complications, which is worthy of clinical promotion and application.

[Effect of salvia miltiorrhiza combined with roxadustat on wound healing of full-thickness skin defects in diabetic rats and its mechanism].

Objective: To explore the effect of salvia miltiorrhiza combined with roxadustat on wound healing of full-thickness skin defects in diabetic rats and its mechanism. Methods: This study was an experimental study. Twenty male 8-week-old Sprague-Dawley rats were used to successfully establish diabetic model, then full-thickness skin defect wounds on their backs were made. The rats were divided into normal saline group, roxadustat alone group, salvia miltiorrhiza alone group, and roxadustat+salvia miltiorrhiza group according to the random number table, with 5 rats in each group. Immediately after injury, the rats in normal saline group were given 5 mL normal saline by gavage, the rats in roxadustat alone group were given 1.5 mg/mL roxadustat suspension by gavage at 25 mg/kg, the rats in salvia miltiorrhiza alone group were given 18 mg/mL salvia miltiorrhiza suspension by gavage at 300 mg/kg, and the rats in roxadustat+salvia miltiorrhiza group were given 19.5 mg/mL roxadustat and salvia miltiorrhiza suspension at roxadustat 25 mg/kg and salvia miltiorrhiza 300 mg/kg. All were administered once a day for 2 weeks. The wounds at 0 (immediately), 4, 8, and 12 d after injury were observed, and the wound healing rates at 4, 8, and 12 d after injury were calculated (n=5). At 14 d after injury, abdominal aortic blood was collected, and hemoglobin, red cell count, and white blood cell count were detected (n=5). The wound tissue was collected for hematoxylin-eosin staining to observe inflammatory infiltration, skin tissue structure, and neovascularization, for Masson staining to observe the proportion of collagen fiber (n=3), for Western blotting to detect the protein expression levels of vascular endothelial growth factor (VEGF), CD31, interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), and IL-1ß (n=3), and for immunohistochemical staining to determine the protein expression levels of epidermal growth factor receptor (EGFR), hypoxia-inducible factor 1α (HIF-1α), and proliferating cell nuclear antigen (PCNA), with sample number of 3. Results: From 0 to 12 d after injury, the wound areas of rats in 4 groups were gradually decreased. At 4 d after injury, the wound healing rates of rats in salvia miltiorrhiza alone group and roxadustat+salvia miltiorrhiza group were significantly higher than those in normal saline group and roxadustat alone group (P<0.05). At 8 d after injury, the wound healing rates of rats in roxadustat alone group and salvia miltiorrhiza alone group were significantly higher than the rate in normal saline group (P<0.05), and the wound healing rate of rats in roxadustat+salvia miltiorrhiza group was significantly higher than the rates in the other 3 groups (with P values all <0.05). At 12 d after injury, the wound healing rates of rats in roxadustat alone group, salvia miltiorrhiza alone group, and roxadustat+salvia miltiorrhiza group were significantly higher than the rate in normal saline group (P<0.05). At 14 d after injury, there were no statistically significant differences in the hemoglobin or red blood cell count of rats in 4 groups (P<0.05). The white blood cell count of rats in roxadustat alone group, salvia miltiorrhiza alone group, and roxadustat+salvia miltiorrhiza group were respectively (24.3±1.2)×109/L, (26.3±2.4)×109/L, and (15.0±0.7)×109/L, which were significantly lower than (33.8±2.7)×109/L in normal saline group (P<0.05); the white blood cell count of rats in roxadustat+salvia miltiorrhiza group was significantly lower than that in roxadustat alone group and salvia miltiorrhiza alone group (with P values both <0.05). At 14 d after injury, a large number of inflammatory cell infiltration, disordered skin tissue structure, and few new blood vessels were observed in the wounds of rats in normal saline group; while a small amount of inflammatory cell infiltration, tight skin tissue structure, and rich neovascularization were observed in the wounds of rats in the other 3 groups. There were no statistically significant differences in the proportion of collagen fiber of wounds in rats among the 4 groups (P>0.05). At 14 d after injury, the protein expression levels of VEGF and CD31 in the wound tissue of rats in roxadustat alone group, salvia miltiorrhiza alone group, and roxadustat+salvia miltiorrhiza group were significantly higher than those in normal saline group (P<0.05), the protein expression level of CD31 in the wound tissue of rats in roxadustat+salvia miltiorrhiza group was significantly higher than the levels in roxadustat alone group and salvia miltiorrhiza alone group (with P values both <0.05). At 14 d after injury, the protein expression levels of IL-6, TNF-α, and IL-1ß in the wound tissue of rats in roxadustat alone group, salvia miltiorrhiza alone group, and roxadustat+salvia miltiorrhiza group were significantly lower than those in normal saline group (P<0.05); the protein expression levels of IL-6 and IL-1ß in the wound tissue of rats in roxadustat+salvia miltiorrhiza group were significantly lower than those in roxadustat alone group and salvia miltiorrhiza alone group (P<0.05); the protein expression level of TNF-α in the wound tissue of rats in roxadustat+salvia miltiorrhiza group was significantly lower than that in salvia miltiorrhiza alone group (P<0.05). At 14 d after injury, the protein expression level of EGFR in the wound tissue of rats in roxadustat+salvia miltiorrhiza group was significantly higher than the levels in the other 3 groups (with P values all <0.05); the protein expression levels of HIF-1α in the wound tissue of rats in roxadustat alone group and roxadustat+salvia miltiorrhiza group were significantly higher than the level in normal saline group (P<0.05), and the protein expression level of HIF-1α in the wound tissue of rats in roxadustat+salvia miltiorrhiza group was significantly higher than that in salvia miltiorrhiza alone group (P<0.05); there were no statistically significant differences in the protein expression level of PCNA in the wound tissue of rats in 4 groups (P>0.05). Conclusions: Roxadustat combined with salvia miltiorrhiza can promote the wound healing of full-thickness skin defects in diabetic rats by promoting blood vessel regeneration and reducing inflammatory response.