Longevity of cross-linked hyaluronic acid filler depending on injection depth: in vivo study using small animal model = Longevity of cross-linked hyaluronic acid filler depending on injection depth: in vivo study using small animal model

다국어 초록 (Multilingual Abstract)

Background: Presenting study estimate the degradation of hyarulonic acid (HA) filler in vivo using rat model to evaluate the longevity of HA fillers depending on injection depth. Objectives: This quantitative analysis demonstrated that HA filler has a longer longevity when injected in deep layer of tissue. Methods: Each 3 Sprague-Dawley rats were assigned to groups based on the sampling timepoints. Four intradermal injections on the one side of back plus four subcutaneous injections on the other side of back of rats was made. Histologic specimens from injected site were obtained at 2 weeks, 5 weeks, 9 weeks, 13 weeks, 20 weeks and 33 weeks after initial implantation. Volumetric analysis using histologic specimen was performed. Results: Volumetric analysis with histologic specimen demonstrated the difference in degradation rate depending on injection depth. Although volume ratio decreased over time in subdermal injection site, subdermal injected site maintained a greater volume ratio than it of intradermal injection site for the duration of the experiment. Time to half of original implant volume was 13 weeks (intradermal site) and 20 weeks (subdermal site) after initial injection, respectively. Conclusion: Presenting study is the first to demonstrate histological change of implanted HA filler materials over time and compare the duration of materials depending on injection depth.