Inhibitory effect of stachydrine on high glucose-induced apoptosis in human lens epithelial cells and its mechanism

Objective  To investigate the effect of stachydrine on the apoptosis of human lens epithelial cells induced by high glucose and its underlying mechanism.

Methods  Cultured human lens epithelial cell line HLE-B3 in vitro was divided into five groups: normal group, mannitol group, high-glucose group, high-glucose+ dimethyl sulfoxide (DMSO) group, and high-glucose+ stachydrine group treated with regular medium, 55 mmol/L mannitol, 55 mmol/L glucose, 55 mmol/L glucose+ 25 μmol/L DMSO, and 55 mmol/L glucose+ 25 μmol/L stachydrine, respectively. The apoptosis rate of cells in each group was detected by flow cytometry. The intracellular reactive oxygen species (ROS) level was measured using the ROS assay kit. The mitochondrial superoxide content was determined by the mitochondrial superoxide assay kit. The mitochondrial membrane potential was assessed using the mitochondrial membrane potential assay kit. The mitochondrial morphology of cells was observed by Mito-Tracker staining.

Results  The apoptosis rates of cells in the normal group, mannitol group, high-glucose group, high-glucose+ DMSO group, and high-glucose+ stachydrine group were (4.09±0.25)%, (4.01±0.23)%, (10.54±0.69)%, (10.72±0.34)% and (6.32±0.37)%, respectively, with a statistically significant overall difference ( F=191.80, P<0.001). The apoptosis rates of the high-glucose group and high-glucose+ DMSO group were significantly higher than those of the normal group, mannitol group and high-glucose+ stachydrine group (all P<0.001). There were statistically significant differences in the mean ROS fluorescence intensity, mean fluorescence intensity of mitochondrial superoxide, mean fluorescence intensity of monomers, mean fluorescence intensity of polymers, mitochondrial membrane potential, mean number of mitochondrial shape factor, mean mitochondrial branch number, and mean mitochondrial area among the five groups ( F=112.50, 84.63, 79.20, 165.90, 73.14, 10.67, 31.65, 52.19; all P<0.05). Compared with the high-glucose group and high-glucose+ DMSO group, the mean ROS fluorescence intensity, mean fluorescence intensity of mitochondrial superoxide, and mean fluorescence intensity of monomers were significantly reduced, and the mean fluorescence intensity of polymers, mitochondrial membrane potential, mean mitochondrial shape factor, mean mitochondrial branch number, and mean mitochondrial area were significantly increased in the normal group, mannitol group and the high-glucose+ stachydrine group (all P<0.05).

Conclusions  Stachydrine may inhibit high glucose-induced apoptosis of human lens epithelial cells by restoring mitochondrial function.