Effect of adlay seed extract on inflammation and fibrogenesis in human corneal activated keratocytes at transcriptional level

Corneal activated keratocytes (CAKs) -representing the injured phenotype of corneal stromal cells- are associated with several corneal diseases. Inflammatory cytokines are the key drivers of CAK formation subsequently leading to fibrogenesis. This study aimed to investigate the effect of adlay seed extract on the expression of genes involved in inflammation (IL-6, IL-1b, LIF) and fibrogenesis (TGF-β) in CAK cells. CAKs (106 cells/10 cm2) were exposed to methanolic (MeOH) and residual (Res) extract of adlay seed (1 mg/ml, 24 h). The control group received the vehicle solution without extract at the same time and condition. Then, RNA extraction, cDNA synthesis, and real-time PCR were performed to quantify the relative expression of IL-6, IL-1b, LIF, and TGF-β in the treated vs. control cells. This study showed that the MeOH extract of adlay seed could significantly downregulate the expression of IL-6 and IL-1b in the CAKs, while the Res extract led to a significant decrease in TGF-β gene expression. We showed that CAK treatment with adlay seed extract could decrease the expression of genes related to inflammation and fibrogenesis. However, the genes to be targeted depended on the method of extraction. This proof-of-concept study could provide groundwork for the treatment of corneal stromal diseases and ocular regenerative medicine in the future.