The effect of chitosan/alginate hydrogel loaded quercetin on wound healing in diabetic rat model

Abstract

Diabetic ulcers often result from a combination of ischemia and oxidative stress, which are exacerbated by inflammation in the wound. Quercetin (3,3',4',5,7-pentahydroxyflavone), a flavonoid with well-documented antioxidant and anti-inflammatory properties, has garnered significant attention in the field of skin regeneration. In addition, chitosan/alginate (C/A) wound dressings have been shown to create a conducive environment for wound healing, leveraging the antimicrobial and anti-inflammatory properties of chitosan, as well as the hydrogel and water-absorbing properties of alginate. Thus, the development of a biologic scaffold, such as quercetin-loaded C/A, may offer a promising alternative for diabetic wound treatment, providing a dermal structure that supports wound healing. In this study, a chitosan-alginate hydrogel was prepared and loaded with varying concentrations of quercetin (0.03%, 0.1%, and 0.3% w/v). Following in vitro evaluation using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), MTT assay, and swelling and degradation tests, the prepared dressings were applied to rats with diabetic wounds, and the resulting scars were analyzed histologically after a 2-week period. The FTIR spectra of the C/A hydrogels revealed characteristic absorption bands corresponding to specific functional groups, including hydroxyl (O-H), amine (N-H), and alkene (C=C) groups. Scanning electron microscopy (SEM) analysis demonstrated successful blending of the hydrogels and adequate cell adhesion. The MTT assay results indicated no significant differences in cellular metabolic activity among the groups. The water uptake levels reached a plateau after 240 min across all experimental groups, suggesting a saturation point in water absorption capacity. The degradation rate of the hydrogel increased substantially from day 1 to day 7, with no significant differences observed among the groups, regardless of quercetin loading. A marked increase in re-epithelialization and collagen deposition was observed across all groups at day 14 compared to day 7, although no significant differences were detected between the quercetin-treated groups and the control or C/A groups. The reduction in wound diameter was significantly greater in the quercetin-treated groups compared to the control and C/A groups at day 14 (p < 0.05). Although our quercetin-loaded chitosan/alginate (2:1) wound dressing did not exhibit significant benefits in terms of re-epithelialization or collagen deposition, it did demonstrate efficacy in reducing wound diameter in diabetic rats.

Keywords: Chitosan/alginate; Diabetic ulcer; Dressing; Hydrogel; Quercetin; Skin regeneration.