Effect of Metformin on Interleukin-6 Expression in Human Fibroblast Cell Aging Model

During skin aging, there is excessive secretion of inflammatory cytokines such as interleukin-6 (IL-6), which can make the ageing process more severe. Metformin has been known to have good anti-inflammatory activity through various pathways, one of which reduces the expression of inflammatory cytokines. This study aimed to analyze the effect of metformin treatment on IL-6 gene expression in an in vitro human fibroblast cell. Human fibroblast cells were obtained through foreskin isolation, and 72 cultured human fibroblast cells were divided into six groups based on cell passages, ranging from the third to the eighth. The expression of IL-6 was assessed in three treatments: negative control (normal cells), metformin 100 µM, and positive control (Vitamin E 50 µM). Treatment and measurement of IL-6 gene expression were carried out using qRT-PCR and calculated using the Livak-Schmittgen method. The results were then compared and analyzed using One-Way Analysis of Variance (ANOVA) and followed by post-hoc analysis. The negative control group had the lowest IL-6 gene expression compared to the metformin group and positive control group. The negative control IL-6 expression showed the highest value at passage 3 (0.166 ± 0.04) and the lowest at passage 6 (0.048 ± 0.04). Meanwhile, the expression of IL-6 positive control passage 4 (5.590 ± 3.34) showed the highest value and passage 7 (0.000 ± 0.00) showed the lowest value. In the metformin group, IL-6 gene expression was highest in passage 5 (0.836 ± 0.15) and lowest in passage 3 (0.078 ± 0.02). Based on treatment, there is a difference in IL-6 gene expression at passage 4 (p-value <0.05) and passage 5 (p-value <0.001). Metformin treatment passage 5 showed a significant difference with negative control (p-value <0.05) and with positive control (p-value <0.05). Our study concluded that the administration of metformin had no effect on IL-6 gene expression in human fibroblasts. However, metformin demonstrated anti-aging potential, as evidenced by a statistically significant difference in IL-6 expression between the negative control and positive control treatment groups.