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Objective To investigate the effects of low dose radiation on the level of oxidative damage and antioxidant in population of high background radiation area of Guangdong.Methods A total of 48 male residents who lived in high background radiation area(HBRA) of Guangdong province and 48 male residents who lived in neighboring Enping control area were chosen as the objectives and control respectively.The peripheral venous blood of two groups was collected,and then the levels of 8-OHdG and TrxR were determined by enzyme linked immunosorbent assay (ELISA).Results Compared with the CA group [(315.39 ± 100.59) ng/ml],the level of 8-OHdG [(272.64 ± 96.85) ng/ml] decreased significantly in HBRA (t =2.121,P ＜0.05).Compared with the CA group [(0.467 ±0.056) ng/ml],the level of TrxR [(0.496 ± 0.044) ng/ml] increased significantly in HBRA (t =-2.823,P ＜ 0.05).The results of multiple linear regression analysis demonstrated that the chronic exposure to low dose of radiation had significant effects on the expression level of 8-OHdG and TrxR (t =-2.327,2.367,P ＜ 0.05) after adjustment for confounding factors such as age,drinking,tea drinking,smoking,medical exposure and stressful events.Conclusions Chronic exposure to low dose radiation may decrease the level of oxidative and enhance the level of antioxidant.
RESUMO
Objective To research the influence of hypoxic preconditioning in anti-oxidative ability of brain tissues and neurological functions in rats after traumatic brain injury.Methods Forty eight adult male Sprague Dawley rats were randomly divided into sham-operated group,hypoxic preconditioning group (HPC),traumatic brain injury group (TBI) and hypoxic preconditioning+traumatic brain injury group (HPCT,n=12).The HPC rat models were made by hypobaric chamber for 3 d (50 kPa,3 h/d) and TBI were induced by Feeney's improved equipment.All rats were killed 24 h after injury,and the neurological functions of each group were evaluated by modified neurologieal severity scale (mNSS);the neuronal survival around contusion area was detected by NeuN immunohistochemical staining,and the protein and mRNA expressions of nuclear transcription factor-related factor 2 (Nrf2) and thioredoxin reductases 2 (TrxR2) in the brain tissues were detected by Western blotting and real-time quantitative PCR.Results The mNSS scores in the TBI and HPCT groups were significantly higher as compared with those in the sham-operated and HPC groups (P＜0.05),but those in the HPCT group was significantly lower than those in the TBI group (P＜0.05).The neuronal survival in the TBI and HPCT groups was decreased as compared with that in the sham-operated and HPC groups (NeuN expressions:0.274±0.033,0.281±0.042 vs 0.124±0.014,0.150±0.019),with significant difference (P＜0.05),while that in the HPCT group was statistically increased as compared with that in the TBI group (P＜0.05).The expressions of Nrf2 and TrxR2 in the brain tissues of TBI and HPCT groups were significantly increased as compared with those in the sham-operated and HPC groups (P＜0.05),and those in the HPCT group was significantly up-regulated as compared with those in the TBI group (P＜0.05).Conclusion HPC can increase the anti-oxidative ability and relieve the neurological functions missing after TBI.