Accelerated wound healing after topical application of hyaluronic acid cotton to hemorrhoidectomy wounds in a rat model.

Purpose: Anal wounds following hemorrhoidectomy can lead to severe pain and postoperative bleeding, impacting patient recovery and quality of life. Hyaluronic acid (HA) stimulates tissue regeneration and wound healing by accelerating cell migration and proliferation. This study aimed to investigate the differences in wound healing rate and completeness of recovery of perianal wounds topically treated with HA-soaked cotton in a murine model. Methods: Forty-eight 8-week-old Sprague-Dawley rats with perianal wounds created using a biopsy punch were divided into 2 groups: simple dressing with gauze (control) and topical HA-soaked cotton. A single application of HA-soaked cotton was administered after surgery. Wound healing rate and completeness of recovery were evaluated by measuring the healed area and conducting histological analyses. Results: The HA-cotton group exhibited a shorter complete wound healing duration compared to the control group (13.9 days vs. 16.4 days, P = 0.031). Differences in wound healing area between the 2 groups were greatest on postoperative day 2 (51.6% vs. 28.8%, P < 0.001). The HA-cotton group exhibited fewer cases of granulation tissue (2 vs. 5) or redness (0 vs. 3) upon complete wound healing. Histologically, the HA-cotton group showed accelerated reepithelialization, rapid shift to lymphocyte-dominant inflammation, enhanced fibroblast proliferation, and increased collagen deposition compared to the control group. Conclusion: Herein, topical application of HA-soaked cotton on perianal wounds in rats resulted in accelerated wound healing, particularly in the initial stages, and improved completeness of recovery, underscoring the potential of the topical application of HA-soaked cotton on hemorrhoidectomy wounds in human patients to improve wound healing.

Effect of orodispersible hyaluronic acid film on palatal mucosa wound healing.

OBJECTIVE: The objective of the study was to evaluate the healing effect of hyaluronic acid films on palatal wounds. MATERIALS AND METHODS: After making 5-mm diameter palatal wounds, 72 rats were randomly assigned to three groups: control, hyaluronic acid gel, and hyaluronic acid film. The animals were sacrificed at 3, 7, and 21 days after the experiment. Clinical, histological, and RT-PCR analyses were performed. Human ex vivo oral mucosa models were used. Histological analysis and pan-cytokeratin staining were performed at 5 days after wound creation. RESULTS: In rat model, both gels and films showed favorable healing on Days 3 and 7 compared with healing in the control (p < 0.05). Film showed remarkable VEGF and α-SMA expression than did the others (p < 0.05). Immunohistochemical analysis showed that film exhibited significantly lower CD68 and greater α-SMA and vimentin expression levels than those in the others (p < 0.05). In human model, re-epithelialization rate of film group was significantly higher than that of the others. Complete epithelial regeneration was confirmed only in film group using pan-cytokeratin staining. CONCLUSIONS: Within the limits of this study, hyaluronic acid film outperformed gels in terms of palatal wound healing in both models.

Comparative In Vivo Study of Solid-Type Pure Hyaluronic Acid in Thread Form: Safety and Efficacy Compared to Hyaluronic Acid Filler and Polydioxanone Threads.

INTRODUCTION: Although various products are commonly used for skin rejuvenation, solid-type hyaluronic acid (HA) as an injectable form has not been researched or utilized. This study aimed to demonstrate the safety and efficacy of solid-type HA in thread form, which differs from the conventional gel-type HA commonly used. METHOD: Solid-type HA threads, conventional HA fillers, and polydioxanone (PDO) threads were inserted into the dorsal subcutaneous layer of mice. Photographs were taken on days 0, 1, 3, and 7, and on day 7, the samples were harvested for histological analysis. Inflammatory reactions and detection of collagen were confirmed through tissue staining, and real-time PCR was conducted to quantify collagen synthesis. RESULTS: In the histological analysis, the PDO threads exhibited a greater inflammatory response compared to the HA threads. Masson's trichrome staining revealed a higher degree of collagen synthesis in the HA thread group compared to the HA filler group. While collagen type 1 expression was significantly higher in the PDO thread group than in the HA thread group, the HA thread group showed higher expression levels of collagen type 3. Furthermore, the PDO thread group demonstrated a statistically significant increase in TGF-ß1 compared to the HA group. CONCLUSION: This in vivo study demonstrated the stable application of solid-type pure HA threads and their potential for inducing collagen production, while also yielding a low inflammatory response. The findings highlight the promising applications of solid-type HA in the field of cosmetic dermatology. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Orodispersible hyaluronic acid film delivery for oral wound healing in rats.

Background/purpose: Oral wound healing undergoes a dynamic process of oral environment. This study aimed to investigate the effects of hyaluronic acid (HA) film on oral wound healing in a rat model. Materials and methods: A total of 60 rats with tongue wounds (5 mm in diameter) were randomly divided into control (n = 20), HA gel (n = 20), and HA film groups (n = 20). The animals were sacrificed on either 3 or 7 days after the experiment. Clinical, histological, and quantitative reverse transcriptase-polymerase chain reaction analysis were performed to evaluate the healing rate, inflammation, re-epithelialization, and gene expression of wound healing biomarkers. Results: The healing rates of HA gel (84.4 ± 9.2%) and HA film (74.0 ± 15.0%) were significantly higher than that of the control (51.7 ± 16.9%) on day 7 (P < 0.001 and P = 0.002, respectively). Histological analysis revealed no significant differences between the groups on day 3. On day 7, only the HA film showed significant improvement in inflammation (P = 0.038) and re-epithelialization (P = 0.011) compared to the control. Regarding wound healing biomarkers, both HA gel and HA film groups showed lower level of COL1α1 expression on day 3 compared to the control. Conclusion: Within the limits of this study, HA film was found to be effective for oral wound healing, particularly for re-epithelialization. This finding suggests that HA film delivery can be beneficial not only for clinical convenience but also for promoting oral wound healing.

Efficacy of hyaluronic acid film on perianal wound healing in a rat model.

PURPOSE: Postoperative pain and delayed wound healing are the main complications following anal surgery associated with poor quality of life. Hyaluronic acid (HA) supports tissue regeneration and rapid wound healing by promoting cell proliferation and migration. We investigated the effects of HA on perianal wound healing in a rat model. METHODS: Forty-eight 8-week-old Sprague-Dawley rats with perianal wounds created by biopsy punch were divided into 3 groups: simple dressing with gauze (control), dressing with topical HA film, and dressing with topical HA gel. HA agents were not reapplied postoperatively. Wound healing was evaluated by measuring the healed area, and histological analyses were randomly performed using hematoxylin and eosin and Masson trichrome staining. RESULTS: Fewer mean days were required for complete wound healing in the HA film and HA gel groups than in the control group (11.6 vs. 11.9 vs. 13.8 days, respectively; P = 0.010). The healed area in the HA film group on day 11 was larger than that in the HA gel and control groups (80.2% vs. 61.9% vs. 53.2%, respectively; P < 0.001). Histologically, the HA film group showed accelerated reepithelialization, a rapid transition to lymphocyte-predominant inflammation, and increased fibroblastic proliferation and collagen deposition compared to the other groups. There was no treatment-related toxicity in the HA application groups. CONCLUSION: Topical application of HA film to perianal wounds improves the wound healing rate in a rat model. This finding suggests a potential benefit of HA film application in promoting wound healing after anal surgery in humans.