Human renal proximal tubule HK-2 cells (CRL-2190™, ATCC, VA, USA) were maintained in keratinocyte serum-free medium (K-SFM, 17005-042, ATCC, VA, USA) in a cell culture incubator. HK-2 cells were subject to 30 mmol/L of glucose for 24 h as high glucose exposure (Cui et al. 2023; (link)Li et al. 2021; (link)Liu et al. 2023) (link). To investigate the roles of wogonin in HG-induced cell toxicity, we exposed HK-2 cells to increasing concentrations of wogonin (1, 2, 4, 8, 16, 32, and 64 µM) for 24 h to determine the suitable concentration for acute toxicity. We chose 8 µM as an optimal concentration for the co-treatment with wogonin and HG based on the cell viability. The treatment with mannitol (8 µM) for 24 h was used as the negative control. Mannitol plus HG medium was used as a control. In brief, cells were divided into three groups: (1) negative control, (2) HG, and (3) HG + wogonin. For in vitro cell viability, the assays were conducted using a commercial 992, Beijing, China) .