Effect of curcumin and lipopolysaccharide on mitochondrial function and cell apoptosis in osteoblasts

Abstract:

Objective：To investigate the effect of lipopolysaccharide（LPS） and curcumin（Cur） on the changes in mitochondrial func－tion and activity and cell apoptosis in osteoblasts. Methods：Primary mouse osteoblasts were cultured in vitro and then divided into control group（N group without any treatment），Cur group（pretreated with 10 μmol/L Cur for 2 hours and then cultured with normal medium for 24 hours），LPS group（treated with 1 mg/L LPS for 24 hours），and Cur+LPS group（pretreated with 10 μmol/L Cur for 2 hours and then treated with 1 mg/L LPS for 24 hours）. A mitochondrial fluorescent probe was used to detect reactive oxygen species （ROS），and the activity of mitochondrial respiratory chain complex，mitochondrial membrane potential，synthesis of ATP in cells，and cell apoptosis were also measured. Results：After the stimulation with 1 mg/L LPS，ROS in the mitochondria was 2.59 times that in the control group. Compared with the control group，the LPS group had a 21% reduction in the activity of respiratory chain complexⅠ， a 26% reduction in the activity of respiratory chain complex Ⅲ，and a 28% reduction in the activity of respiratory chain complex Ⅳ， as well as a 32% reduction in mitochondrial membrane potential，an amount of ATP synthesis of 0.79±0.06 μmol/mg protein，and a 3.2-fold increase in the number of apoptotic cells. Com－pared with the LPS group，the Cur+LPS group had a significant reduction in ROS（1.48±0.21 vs. 2.59±0.32，P=0.003），signifi－cant increases in the activities of respiratory chain complexⅠ（0.98±0.02 vs. 0.79±0.03，P=0.000），Ⅲ（0.93±0.03 vs. 0.74±0.03，P=0.004），and Ⅳ（0.92±0.05 vs. 0.72±0.02，P=0.009），a sig－nificant increase in mitochondrial membrane potential（0.91±0.04 vs 0.68±0.04，P=0.002），a significant increase in ATP synthesis（1.53±0.05 vs. 0.79±0.06，P=0.000），and a significant reduction in the number of apoptotic cells（1.67±0.42 vs. 5.33±0.80，P=0.002）. Conclusion：Osteoblasts pretreated with Cur had a significant improvement in mitochondrial function and a significant reduction in the number of apoptotic cells，which provide an experimental basis for the application of Cur in clinical treatment of periodontitis.