Role of Calcium Homeostasis in Apoptosis of Embryonic Rat Cortical Neurons Induced by Dibutylphthalate

Objective To study the role of calcium homeostasis in the apoptosis of rat cortical neurons induced by dibutylphthalate (DBP).

Methods  Neurons were sampled from the cortex of pregnant rats. The cortical neurons were treated with 25, 50, and 100 mg/L DBP; meanwhile, 10 μmol/L calcium chelator (BAPTA-AM) was added into the above combinations. The apoptosis rates, intracellular free calcium concentrations Ca²⁺_i, reactive oxygen species (ROS), and mitochondrial membrane potential of the cortical neurons were detected by flow cytometry.

Results  After treated with 25, 50, and 100 mg/L DBP, the apoptosis rate (12.27±0.93)%, (18.53±0.87)%, and (27.63±1.06)%, respectively, Fluo-3/AM fluorescence intensity (10623±826)%, (14 815±732)%, and (18 328±708)%, level of ROS (10.21±1.05)%, (29.23±1.35)%, and (34.68±1.03)%, and decrease rate of mitochondrial membrane potential (30.71±1.81)%, (45.30±3.25)%, and (53.00±4.29)% were all higher than those of the control group (all Ps < 0.05) in a dose-response manner (r=0.977, r=0.970, r=0.962, r=0.914, all Ps < 0.05). After treated with BAPTAAM, the apoptosis rates, Fluo-3/AM fluorescence intensity, level of ROS, and decrease rate of mitochondrial membrane potential of the cortical neurons were decreased compared with corresponding DBP only groups (all Ps < 0.05).

Conclusion  DBP could in duce rat cortical neuron apoptosis, and BAPTA-AM could blunt the apoptosis through decreasing Ca²⁺_i, suggesting that the disequilibrium of calcium homeostasis might promote the apoptosis of rat cortical neurons induced by BBP.