Dmem basic 1x

Fetal bovine serum (FBS) was purchased from AusGeneX (Molendinar, Australia, CAT NO. FBS500-S); DMEM basic (1X) was from Gibco Life Technologies (Shanghai, China); penicillin/streptomycin solution (100 U/mL and 100 mg/mL, respectively), 2′, 7′-dichlorodihydrofluorescein diacetate (DCFH-DA), and Cellular grade DMSO were from Beijing Solarbio Science & Technology Co., Ltd. (Beijing, China); 3-(4,5-dimethyl-1,3-thiazol-2-yl)-2,5-diphenyl-2H-tetrazol-3-ium bromide(MTT) was obtained from Biosharp Life Technology Co., Ltd. (Hefei, China); Hoechest 33342, Mito-Tracker Green, and Lyso-Tracker Green were from Beyotime Biotechnology Co., Ltd. (Shanghai, China). All cells were cultured in a CO₂ incubator (Wiggens, WCI-180, Beijing, China). All the in vitro fluorescence images experiments were obtained by using an Olympus IX73 + DP73 inverted microscope and laser confocal microscope (Carl Zeiss LSM 900, Jena, Germany). Hypoxic condition was created by coverslips (Citoglas, Hong Kong, China) and a hypoxia chamber (Stemcell Technologies, Cat 27310, Kent, WA, USA). Cytotoxicity assay was performed using an LED light (F&V, Z96kit, Fuijan, China) as irradiation source.

HCECs were plated in 96-well plates at a density of 10⁴ and incubated for 12 h. Then the medium was placed with 100 μL of DMEM basic (1X) (Gibco) containing different concentrations of MSCExo-Ce (0, 50, 100, 200, μg mL⁻¹). After culturing for 24 h, the cell viability was measured using Cell Counting Kit-8 (CCK-8) (Solarbio Life Sciences, Beijing, China) and a live/dead assay (Beyotime Biotechnology, Yancheng, China).