Chondrocalcinosis ; Humans ; Temporomandibular Joint ; Temporomandibular Joint Disorders

Objective To investigate the protective effect of polydatin(PLD)on primary cultured rat cortical neurons induced by β-amyloid protein(Aβ25-35)and its possible mechanism.Methods Cortical neurons were isolated from SD rats and primarily cultured,and then divided into control group,PLD group,Aβ25-35 group and Aβ25-35+PLD group.Cell viability was detected by MTT as-say,intracellular and mitochondrial reactive oxygen species(ROS)levels were detected by dichlo-rofluorescein diacetic acid probe or MitoSOX Red staining,opening of mitochondrial membrane permeability transition pore(MPTP)was detected by MPTP kit,and contents of cytochrome C(Cyt C)and mitochondrial transcription factor A(TFAM)were detected by Western blotting.In addition,the activity of intracellular electron transport chain complexes(including complexes Ⅰ,Ⅱ,Ⅲ and Ⅳ)and the level of adenylate triphosphate(ATP)were determined.High performance liquid chromatography(HPLC)was conducted to determine the content of 8-hydroxydeox-yguanosine(8-OHdG)in the mitochondria.Results Compared with the control group,cell vitali-ty,mitochondrial fluorescence intensity,activities of mitochondrial respiratory chain enzymes(complex Ⅰ,Ⅱ,Ⅲ and Ⅳ),intracellular ATP and mitochondrial TFAM expression were signifi-cantly decreased in the cortical neuron from the Aβ25～35 group(P＜0.05,P＜0.01).Compared with the Aβ25-35 group,mitochondrial fluorescence intensity,mitochondrial respiratory chain enzyme activity(complex Ⅰ,Ⅱ,Ⅲ,Ⅳ),intracellular ATP and mitochondrial TFAM expression were obviously increased in the PLD group,and intracellular and mitochondrial ROS levels were nota-bly decreased after cortical neuron exposure for 3,6,12 and 24 h(P＜0.05,P＜0.01).The ratio of cytoplasmic/mitochondrial Cyt C and mitochondrial level of 8-OHdG were statistically lower in the Aβ25-35+PLD group than the Aβ25-35 group[3.02±0.28 vs 5.73±0.45,P＜0.05;(8.07±1.45)× 106 dG vs(16.07±2.29)X 106 dG,P＜0.05].Conclusion PLD can effectively protect cortical neu-rons against Aβ25-35-induced injury,which may be partially by its inhibiting mitochondrial oxida-tive stress and improving mitochondrial function.