ABSTRACT
Objective The genotoxicty and its molecular mechanism of environmental tobacco smoke (ETS) were discussed through the oxidative DNA damage induced by environmental tobacco side_stream smoke(ETSS). Methods DNA adduct 8_hydroxydeoxyguanosine (8_OHdG) was used as a biomarker of oxidative DNA damage. The level of 8_OHdG in DNA exposed to ETSS was detected by HPLC_EC.On the molecular biological level,the biological oxidative ability of ETSS on DNA molecule was studied.Organic and inorganic components in ETSS were analyzed by GC_MS and AAS respectively. Results Particles and VOCs in ETSS could directly induce oxidative DNA damage and form 8_OHdG.It was found that there were 123 and 84 kinds of organic compounds in particles and volatile organic compounds of tobacco smoke side stream,and 7 kinds of inorganic compounds in ETSS.Some components especially quinones and polyphenols in ETS,could produce free radicals in vitro by the auto_oxidation without any biological activity systems,and with the catalytic reaction of metals,the DNA aduct 8_OHdG was produced. Conclusion It was proved that ETS had biological oxidative ability on DNA and expressed direct genotoxicity.8_OHdG was a fine biomarker of effect of oxidative DNA damage.
ABSTRACT
The contents of dopamine (DA) and its metabolites, homovanillic acid (HVA) and 3,4-dihydroxyphenyl acetic acid(DOPAC), in both striata were determined with HPLC-EC technique in each of 28 albino rats, which were divided into 3 groups (bilateral lesioned, unilateral lesioned and healthy control groups). Among the unilateral lesioned rats, three indices such as DA, HVA/DA and DOPAC/DA in the lesioned striata were 22.27％, 420.00％ and 199.75％ of those of the intact striata, respectively. This suggests that there may be an enhanced compensatory DA release in the striatum ipsilateral to the lesion of the rat. Having compared the lesioned striata of unilateral lesioned rats with those of bilateral lesioned animals, and the intact striata of unilateral lesioned rats with those of the control ones, we did not find any significant differences in DA, HVA/DA or DOPAC/DA. The result implies that the compensatory DA release in the lesioned striatum probably accounts for the mechanism of the ipsilateral nigrostriatal system, not for the crossed nigrostriatal fibers.