Histological Study on the Effect of Hyaluronic Acid Injection on the Skin of Adult and Aged Albino Rats

In the 2019 study, 45 female albino rats were divided into groups to assess the effects of hyaluronic acid (HA) injections on their skin. Group I served as the control with 20 adult rats, Group II consisted of 15 adult rats injected with 0.1 ml of HA and further subdivided based on the time of sacrifice (7, 60, and 90 days), and Group III included 10 aged rats, with 5 as a control and 5 injected with HA and sacrificed after 30 days. The results showed that HA injections significantly increased the thickness of subcutaneous tissue, collagen and elastic fibers, and CD34 positive endothelial cells in comparison to the control and aged rats. Additionally, active fibroblasts at the injection site indicated an enhanced ability to synthesize collagen and elastic fibers. The conclusion drawn from the study was that HA filler injections stimulated vascularization and fibroblast activity, which protected the skin from aging in adults and improved skin defects in aged rats.