Background: MicroRNAs (miRNAs) are abnormally expressed in varying ocular diseases, including agerelated cataract. However, the roles of miR-182-5p in age-related cataract progression remains unclear.Methods: The expression of miR-182-5p in HLE-B3 cells were detected by qRT-PCR. HLE-B3 cells were transfected with miR-182-5p mimics. CCK-8, EdU, flow cytometry, 2',7'-dichlorodihydrofluorescein diacetate, JC-1 kit, and Western bolt were used to assess the cell viability, proliferation, apoptosis, reactive oxygen species (ROS) level, mitochondrial membrane potential (MMP), and protein expression, respectively, in vitro . The target relationship of miR-182-5p and NOX4 was confirmed using dual-luciferase reporter gene analysis.Results: We found that miR-182-5p was significantly decreased by the H 2 O 2 exposure.Overexpression of miR-182-5p promoted cell proliferation, inhibited ROS production and apoptosis in H 2 O 2 -induced HLE-B3 cells. Moreover, p-p-38, p-ERK, and p-JNK were up-regulated in H 2 O 2treated HLE-B3 cells, and overexpression of miR-182-5p reversed the effect of H 2 O 2 on HLE-B3cells. In addition, dual-luciferase reporter assay substantiated that NOX4 was a direct target and downregulated by miR-182-5p.Conclusions: We concluded that miR-182-5p inhibited lens epithelial cells apoptosis through regulating NOX4 and p38 MAPK signaling, providing a novel biomarker for treatment of age-related cataract.