Neurotoxicity of benzo [a] pyrene and its effects on heat stress protein 70 and heat stress protein 90β in brain tissue of mice

Baijie TU; Yang WANG; Tangchun WU

ABSTRACT

BACKGROUND:

Benzo[a] pyrene(BaP) is kind of polyaromatic hydrocarbon which is a chemical pollutant extensively existing in living and productive environments. It is found overseas that it has neurotoxic effects under certain conditions.

OBJECTIVE:

To study the neurotoxicity of BaP and its effects on expression of two heat stress proteins(HSPs) HSP70 and HSP90β in brain tissue of mice.

DESIGN:

Randomized case control study of experimental animals.

SETTING:

Laboratory of thermobiology and molecular toxicology of a unversity, department of preventive medicine of a university.MATERIALS The experiment was conducted in the Thermobiology and Molecular Toxicity Laboratory, Tongji Medical College, Huazhong Science and Technology University. Fifty male Kunming mice were randomly divided into 5 groups with each of 10 mice including 3 administrated groups, 1 vehicle group and 1 control group. All mice in 3 exposed groups were intraperitoneally administrated BaP dissolved in corn oil at dose levels of 7.8mg/kg, 3.2 mg/kg and 1.3 mg/kg respectively for four times per week. The mice in vehicle group received an equal volume of com oil and the mice in control group received no additional treatment.

METHODS:

The signs of neurotoxicity in each group were examined and recorded during the administration. At the end of 8-week administration, the brains were excised to calculate brain tissue organ coefficient. Western blot method was used to assay the HSP70 and HSP90β.MAIN OUTCOME

MEASURES:

Effects of BaP on HSP70 and HSP90βin brain tissue of mice.Bap exposure groups was much lower than that of control group( P ＜ 0. 01,P ＜ 0. 001 ) while the organ coefficient of high dose group was much of HSP70 was characterized by greatly increased expression in low dose group while the relative expression of HSP90β was increased in middle and high dose groups.

CONCLUSION:

BaP has certain neurotoxic effects. With the increase of toxic dose, the expression of HSP90β increases which can be used as signal of toxic damage under certain conditions.