[Effects of polybrominated diphenyl ether-153 lactation exposure on the concentrations of intracellular calcium ion and calcium-activated related enzymes levels of adult rats' cerebral cortex].
OBJECTIVE
To investigate the effects of polybrominated diphenyl ether-153 (BDE-153) exposure during lactation period on the calcium ion (Ca(2+)) concentration and calcium-activated enzyme levels in cerebral cortical cells among adult rats and to provide a scientific basis for the study on the developmental neurotoxicity of BDE-153.


METHODS
Forty newborn male rats were randomly and equally divided into four groups according to their body weights and litters: 1, 5, and 10 mg/kg BDE-153 groups and olive oil solvent control group. On postnatal day 10 (PND 10), the BDE-153 groups were administrated BDE-153 (0.1 ml/10 g body weight) by intraperitoneal injection, while the olive oil solvent control group was given an equal volume of olive oil. Two months later, these rats were decapitated, and the cerebral cortex was separated quickly on an ice-cold dish. The Ca(2+) concentration in cerebral cortical cells was measured by flow cytometry. The activities of calcineurin (CaN) and Ca(2+)-Mg(2+)-ATP enzyme were determined by colorimetric method. The mRNA and protein expression of calpain-1 and calpain-2 was measured by real-time quantitative PCR and Western blot.


RESULTS
The mean fluorescence intensities of intracellular Ca(2+) in control group and 1, 5, and 10 mg/kg BDE-153 groups were 10.83, 1.48, 1.93, and 0.62, respectively; the 1, 5, and 10 mg/kg BDE-153 groups had significantly lower intercellular Ca(2+) concentrations than the control group (P < 0.05). The activities of CaN and Ca(2+)-Mg(2+)-ATP enzyme and mRNA and protein expression of calpain-1 showed no significant differences between the 1, 5, and 10 mg/kg BDE-153 groups and control group (P > 0.05). The protein expression of calpain-2 increased as the dose of BDE-153 rose. Compared with the control group (mRNA: 0.81±0.26; protein: 0.15±0.07), the 5 and 10 mg/kg BDE-153 groups had significantly higher mRNA expression of calpain-2 (5 mg/kg BDE-153 group: 1.16±0.52; 10 mg/kg BDE-153 group: 1.32±0.23) and significantly higher protein expression of calpain-2 (5 mg/kg BDE-153 group: 0.31±0.07; 10 mg/kg BDE-153 group: 0.37±0.06) (P < 0.05). The 10 mg/kg BDE-153 group had significantly higher protein expression of calpain-2 than the 1 mg/kg BDE-153 group (0.37±0.06 vs 0.22±0.07, P < 0.05).


CONCLUSIONS
Ca(2+-) mediated calpain-2 activation may be one of the main mechanisms of BDE-153 neurotoxicity.
School of public health, Shanxi Medical University, Taiyuan 030001, China.
Hong-mei
HM
Zhang
Xin
X
Li
Li-jun
LJ
Chang
Huan-jun
HJ
Zhang
Qiao
Q
Niu
D000818:Animals; D000831:Animals, Newborn; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism; D019703:Calcineurin / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002154:Calpain / Q000378:metabolism; D002540:Cerebral Cortex / Q000378:metabolism*; D008297:Male; D011075:Polybrominated Biphenyls / Q000633:toxicity*; D051381:Rats; D017207:Rats, Sprague-Dawley
D011075:Polybrominated Biphenyls; C517828:hexabrominated diphenyl ether 153; D019703:Calcineurin; D002154:Calpain; D017301:Ca(2+) Mg(2+)-ATPase; D002118:Calcium