Effects of Radiation-Induced Skin Injury on Hyaluronan Degradation and Its Underlying Mechanisms.

Radiation-induced skin injury (RISI) is a frequent and severe complication with a complex pathogenesis that often occurs during radiation therapy, nuclear incidents, and nuclear war, for which there is no effective treatment. Hyaluronan (HA) plays an overwhelming role in the skin, and it has been shown that UVB irradiation induces increased HA expression. Nevertheless, to the best of our knowledge, there has been no study regarding the biological correlation between RISI and HA degradation and its underlying mechanisms. Therefore, in our study, we investigated low-molecular-weight HA content using an enzyme-linked immunosorbent assay and changes in the expression of HA-related metabolic enzymes using real-time quantitative polymerase chain reaction and a Western blotting assay. The oxidative stress level of the RISI model was assessed using sodium dismutase, malondialdehyde, and reactive oxygen species assays. We demonstrated that low-molecular-weight HA content was significantly upregulated in skin tissues during the late phase of irradiation exposure in the RISI model and that HA-related metabolic enzymes, oxidative stress levels, the MEK5/ERK5 pathway, and inflammatory factors were consistent with changes in low-molecular-weight HA content. These findings prove that HA degradation is biologically relevant to RISI development and that the HA degradation mechanisms are related to HA-related metabolic enzymes, oxidative stress, and inflammatory factors. The MEK5/ERK5 pathway represents a potential mechanism of HA degradation. In conclusion, we aimed to investigate changes in HA content and preliminarily investigate the HA degradation mechanism in a RISI model under γ-ray irradiation, to consider HA as a new target for RISI and provide ideas for novel drug development.

Development of bovine serum albumin-modified Fe3O4 embedded in porous α-ketoglutaric acid/chitosan (BSA/Fe3O4@KA/CS): A magnetically targeted hemostatic dressing for deep and irregular wounds.

Severe bleeding from deep and irregular wounds poses a significant challenge in prehospital and surgical settings. To address this issue, we developed a novel chitosan-based hemostatic dressing with a magnetic targeting mechanism using Fe3O4, termed bovine serum albumin-modified Fe3O4 embedded in porous α-ketoglutaric acid/chitosan (BSA/Fe3O4@KA/CS). This dressing enhances hemostasis by magnetically guiding the agent to the wound site. In vitro, the hemostatic efficacy of BSA/Fe3O4@KA/CS is comparable to that of commercial chitosan (Celox™) and is not diminished by the modification. In vivo, BSA/Fe3O4@KA/CS demonstrated superior hemostatic performance and reduced blood loss compared to Celox™. The hemostatic mechanism of BSA/Fe3O4@KA/CS includes the concentration of solid blood components through water absorption, adherence to blood cells, and activation of the endogenous coagulation pathway. Magnetic field targeting is crucial in directing the dressing to deep hemorrhagic sites. Additionally, safety assessments have confirmed the biocompatibility and biodegradability of BSA/Fe3O4@KA/CS. In conclusion, we introduce a novel approach to modify chitosan using magnetic guidance for effective hemostasis, positioning BSA/Fe3O4@KA/CS as a promising candidate for managing various wounds.

Effect of different drying methods on the structure and properties of porous starch.

In order to investigate the effects of different drying methods on the properties of porous starch. The present study used four drying methods, namely hot air drying (HD), spray drying (SPD), vacuum freeze drying (FD) and supercritical carbon dioxide drying (SCD) to prepare maize and kudzu porous starch. Findings indicated that the physicochemical properties (e.g., morphology, crystallinity, enthalpy value, porosity, surface area and water absorption capacity as well as dye absorption capacity, particle size) of porous starch were significantly affected by the drying method. Compared with other samples, SCD-treated porous starch exhibited the highest surface areas of the starch (2.943 and 3.139 m2/g corresponding to kudzu and maize, respectively), amylose content (22.02 % and 16.85 % corresponding to kudzu and maize, respectively), MB and NR absorption capacity (90.63 %, 100.26 % and 90.63 %, 100.26 %, corresponding to kudzu ad maize, respectively), and thermal stability, whereas HD-treated porous starch showed the highest water-absorption capacity (123.8 % and 131.31 % corresponding to kudzu and maize, respectively). The dye absorption of the maize and kudzu porous starch was positively correlated with surface area, according to Pearson's correlation analysis. Therefore, in this study, our aim was to explore the effects of different drying methods on the Structure and properties of porous starch, and provide reference for selecting the best drying method for its application in different fields.