Administration of Bajakah (Spatholobus littoralis Hassk) Stem Ethanol Extract Cream Inhibited the Increase of MMP-1 Expression and Decrease of Collagen Number in Male Wistar Rats (Rattus norvegicus) Exposed to Ultraviolet B

Background: Exposure to ultraviolet B (UV-B) rays causes skin aging characterized by an increase in the expression of matrix metalloproteinase-1 (MMP-1) and a decrease in the amount of collagen through increased free radical production. To prevent skin aging due to UV-B exposure, it is necessary to additionally provide antioxidants as a measure to inhibit the skin aging process in Wistar rats exposed to ultraviolet B rays. One source of antioxidants is a natural ingredient such as bajakah (Spatholobus littoralis hassk) stem. The ethanol extract of the Bajakah stem contains antioxidants such as phenols, flavonoids, and tannins. The purpose of this study was to prove that the administration of Bajakah stem ethanol extract cream inhibits the increase MMP-1 expression and decrease of collagen number in male Wistar rats exposed to UV-B. Methods: This study used a post-test only control group design. Subjects were male rats (Rattus norvegicus), Wistar strain, aged 2-3 months, weighing 180-200gram which were divided randomly into two groups. The control group (n = 18 rats) was exposed to UV-B rays and placebo cream (0.2 mg/cm2), while the treatment group (n = 18 rats) was exposed to UV-B rays and Bajakah stem ethanol extract cream 15 % (0.2 mg/cm2). The cream was administered 20 minutes before and 4 hours after exposure to UV-B rays (3 times a week, the total dose of 840 mJ/cm2). Twenty-four hours after the last radiation, a punch biopsy of skin tissue was prepared for histological examination followed by immunohistochemical assay (for MMP-1) and Sirius red (for collagen) staining. Results: The expression of MMP-1 in the control group was 24.3 ???? 6.20 % and the treatment group was 11.5 ???? 3.21 %. The comparative analysis using the independent T-test showed a p-value of <0.001 which indicates that there was a significant difference in MMP-1 expression between the control and treatment groups. In addition, the amount of collagen in the control group was 63.1 ???? 3.94 % and th