Influence of chronic fluorosis on expression of quinone oxidoreductase-1 and heme oxygenase-1 in rat brains / 中华地方病学杂志

ABSTRACT

Objective To investigate the changes of expression of quinone oxidoreductase-1 (NQO1) and heme oxygenase-1 (HO1) at protein and mRNA levels in the brains of rats with chronic fluorosis,effect on NF-E2-related factor 2/antioxidant response element (Nrf2/ARE) signal pathway,and reveal the mechanism of brain damage induced by the disease.Methods SD rats were randomly divided to two groups of 30 each (half females and half males),e.g.the normal control group (drinking water containing less than 0.5 mg/L of fluorine) and fluoride exposed group (drinking water containing 50.0 mg/L sodium fluoride,NaF).All rats were examined at the 10 months after feeding NaF.Dental fluorosis of rats was observed; the fluoride contents in urine and bone were detected by fluoride-ion selective electrode; protein and mRNA levels of NQO1 and HO1 in brains were detected by Western blotting and quantitative real timePCR,respectively.Results The dental fluorosis was observed,and contents of fluoride in urine [(2.16 ± 0.39)mg/L] and bone [(211.07 ± 40.52)mg/kg] determined in the rats of the fluoride group were higher than those of controls [(1.70 ± 0.24)mg/L,(34.67 ± 11.15)mg/kg,t =2.11,3.23,all P＜ 0.05].The protein expression levels of NQO1 and HO1 in the brains of rats with fluorosis [(255.2 ± 14.3) ％ and (187.2 ± 11.1)％] were also higher than those of controls [(100.0 ± 12.2)％,(100.0 t 8.9)％,t =2.14,2.05,all P ＜ 0.05]; the mRNA levels of NQO1 and HO1 [(210.2 ± 9.8)％ and (154.5 ± 7.4) ％] in the rats of the fluoride group were increased as compared to those of controls [(100.0 ± 10.4)％,(100.0 ± 9.7)％,t =2.33,2.75,all P ＜ 0.05].Conclusion The expression of NQO1 and HO1 in brain of rats with fluorosis are significantly increased,which may be due to the activation of Nrf2/ARE signal pathway and may play a compensative role in enhancing antioxidant ability.