Hypertrophic scar development is a complication associated with wound healing, impacting local appearance and function. The type I/III collagen ratio affects the extent of hypertrophic scarring; a reduced ratio can ameliorate this. In this study, recombinant human collagen type III was developed. Liquid chromatography–tandem mass spectrometry was used to determine its amino acid sequence and confirm its high level of homology with natural human type III collagen. Recombinant human collagen type III displayed no cytotoxicity and did not confer skin irritation and sensitization. Immunofluorescence and western blot analyses of histidine following incubation with fibroblasts suggested cell entry of recombinant human collagen type III. Furthermore, recombinant human collagen type III promoted the synthesis of the natural type III collagen in fibroblasts, resulting in a more obvious increase of type III collagen content in fibroblasts than that of type I collagen, and then decreased the ratio of type I/III collagen. The results of 5-ethynyl-2ʹ-deoxyuridine staining assay suggested enhanced fibroblast proliferation. Following local injection of recombinant human collagen type III, rabbit ear scarring was significantly reduced after 60 days. Vancouver Scar Scale evaluation showed that all index scores were significantly reduced. Western blotting and Picro-Sirius red staining showed that the natural type III collagen increase in scar tissue was greater than that of type I collagen, decreasing the type I/III ratio. In summary, recombinant human collagen type III can be taken up by fibroblasts and promote natural collagen synthesis—especially that of type III—thereby reducing the type I/III ratio and improving hypertrophic scarring.

Objectives: Even though disinfectants are commonly used in clinical practice and daily life, there are few studies on their antibacterial ability and cytotoxicity, which are closely related to the safety and effectiveness of their use. To provide a basis for the use of disinfectants, the cytotoxicity and antibacterial activity of three most commonly used disinfectants, povidone-iodine, chlorhexidine acetate and polyhexamethylene biguanide (PHMB), were investigated. Design: A CCK-8 assay was used to measure the activities of human fibroblasts (HF) and keratinocytes (HaCat), the two most important cells in wound healing, following their exposure to disinfectants. The effects of different times and concentrations were included. The antibacterial activity of disinfectants against Staphylococcus aureus, Acinetobacter baumannii, Klebsiella pneumoniae was reflected by their minimum inhibitory concentration and minimum bactericidal concentration. Results: All three disinfectants showed strong cytotoxicity in direct contact with HF and HaCat cells. Cytotoxicity increased with increasing exposure time and concentration. S. aureus , A. baumannii and K. pneumoniae comprised 70%, 55% and 85% of the strains sensitive to povidone iodine; 50%, 45% and 80% of the strains sensitive to chlorhexidine acetate; and 60%, 45% and 80% of the strains sensitive to PHMB, respectively. Conclusions: All three disinfectants were cytotoxic; therefore, it is necessary to pay attention to the use time and concentration in the clinical setting. All three disinfectants were cytotoxic, with povidone-iodine being the most cytotoxic even at low concentrations. PHMB had better antibacterial efficacy against S. aureus and is suitable for the treatment of shallow wounds primarily. All three tested bacteria were significantly more sensitive to PHMB than to the other disinfectants.

Scar formation can be effectively prevented when the proportion of collagen type I (Col I)/type III (Col III) is reduced. Unlike Col III, recombinant human collagen type III chain (RHC III chain) does not possess a triple helical structure. This study aimed to elucidate the capacity of fibroblasts to uptake RHC III chain, reduce the Col I/Col III ratio and determine its effects on wound healing and scar. RHC III chain demonstrates qualified cell compatibility. In cell experiments, immunofluorescence and western blot (WB) analyses revealed an increase in the polyhistidine tag level, indicating that RHC III chain in internalized by these cells. Transmission electron microscopy showed increased intracellular phagocytic activity, indicating that RHC III chain enters fibroblasts by endocytosis. The immunofluorescence and WB showed that Col III synthesis enhanced, and Col I/Col III ratio reduced. However, the polyhistidine tag disappeared with time, indicating that RHC III chain degraded within cells and then synthesized into Col III. The content of newly synthesized Col III increases, but real-time fluorescence quantitative showed a decrease in Col III related gene content suggests the formation of negative feedback. However, due to the sufficient raw materials, the amount of Col III synthesis is still increasing, leading to the reduction of the ratio of type I collagen/type III collagen, which beneficial to wound healing and reduce scar hyperplasia. In animal experiments, the SD rat full-thickness skin defect model of wound suggests that RHC III chain also takes effect through endocytosis and ultimately promotes wound healing. The rabbit ear scar model suggests that RHC III chain inhibits scar proliferation by reducing the ratio of Col I/Col III. In summary, RHC III chain was endocytosed by fibroblasts to promote native Col III synthesis, as well as promote wound healing and reduce scar hyperplasia.

Cell migration and proliferation are conducive to wound healing; however, regulating cell proliferation remains challenging, and excessive proliferation is an important cause of scar hyperplasia. Here, we aimed to explore how a subvacuum environment promotes wound epithelisation without affecting scar hyperplasia. Human immortalized keratinocyte cells and human skin fibroblasts were cultured under subvacuum conditions (1/10 atmospheric pressure), and changes in cell proliferation and migration, target protein content, calcium influx, and cytoskeleton and membrane fluidity were observed. Mechanical calcium (Ca²⁺) channel blockers were used to prevent Ca²⁺ influx for reverse validation. A rat wound model was used to elucidate the mechanism of the subvacuum dressing in promoting healing. The subvacuum environment was observed to promote cell migration without affecting cell proliferation; intracellular Ca²⁺ concentrations and PI3K, p‐PI3K, AKT1, p‐AKT 1 levels increased significantly. The cytoskeleton was depolymerized, pseudopodia were reduced or absent, and membrane fluidity increased. The use of Ca²⁺ channel blockers weakened or eliminated these changes. Animal experiments confirmed these phenomena and demonstrated that subvacuum dressings can effectively promote wound epithelisation. Our study demonstrates that the use of subvacuum dressings can enhance cell migration without affecting cell proliferation, promote wound healing, and decrease the probability of scar hyperplasia.