[Apoptosis and Ca~(2+) balance disorder of BV-2 cells induced by polychlorinated biphenyl].

OBJECTIVE: To study the neurotoxicity and mechanism of polychlorinated biphenyl( PCB) in BV-2 cells.

METHODS: The experiment was divided into control group and PCB118, 138, 153, 180 treated group, the dosages were 0. 000, 0. 015, 0. 030, 0. 050, 0. 100, 0. 150 μmol/L. Through the statistical analysis of the survival rate of the cells, the final dose was divided into low, middle and high dose levels. Among them, the high dose group except PCB118 was 0. 15 μmol/L, the PCB138, 153, 180 concentration was 0. 015, 0. 05 and 0. 1 μmol/L for the low, medium and high dose groups. In vitro culture of mouse microglia cells with different doses of PCB after exposure, CCK-8 method to detect cell growth and viabilities; FITC Annexin V/PI method to detect cell apoptosis rate; detection of lactate dehydrogenase( LDH) release by ELISA kit; fluorescence probe method( Fluo-4 AM) to detect the intracellular calcium content changes.

RESULTS: CCK-8 and FITC Annexin V/PI double staining experiments showed that PCB118, 138, 153, 180 could inhibit cell activity, and with the increase in dose, cell survival rate decreased, apoptosis rate increased. PCB118 dose in 0. 15 μmol/L toxicity increased, cytoactive was reduced to( 66. 56 ± 0. 10) %, apoptosis rate increased to( 27. 39 ± 1. 80) %; PCB138, 153 in 0. 1 μmol/L cell survival rate reached( 66. 66 ± 0. 10) % and( 67. 17 ± 0. 12) %, apoptosis rate reached( 48. 77 ± 2. 43) % and( 56. 42 ± 3. 59) %; PCB180 dose of 0. 015μmol/L cell survival rate reached( 92. 07 ± 0. 38) %, cell apoptosis rate was( 6. 82 ±0. 51) %, significantly higher than that of the control group, the difference was statistically significant( P < 0. 05). LDH assay showed that the release amount of LDH was proportional to the dose of PCB. The lactate dehydrogenase amounts of PCB118, 138, 153 and 180 were( 523. 78 ± 13. 58) U/L, ( 430. 37 ± 22. 03) U/L, ( 540. 58 ± 13. 08)U/L, ( 411. 88 ± 21. 92) U/L, which were significantly higher than those in the control group, the difference was statistically significant( P < 0. 05). The result of Fluo-4 and AM showed that the average fluorescence intensity of intracellular calcium( Ca~(2+)) in PCB exposed group increased obviously. The average fluorescence intensity of Ca~(2+) in the PCB118, 138, 153 and 180 groups was( 10. 14 ± 2. 36), ( 32. 47 ± 1. 56), ( 16. 54 ± 0. 97)and( 40. 46 ± 2. 19) when the dose was 0. 015 μmol/L, significantly higher than that of the control group, the difference was statistically significant( P < 0. 05).

CONCLUSION: PCB could cause neurotoxicity damage, increase LDH, destroy cell membrane integrity, induce the balance disorder of cell calcium and lead to the cell apoptosis.