RESUMO
Objective To explore the effects of different vitamin A(VA) levels on thyroid cells apoptosis and its gene expression of mice taking excessive iodine. Methods Kunming mice were randomly divided into 6 groups according to body weight 3 weeks after born: normal control(NI) group, high iodine(HI) group, low vitamin (LVA) group, high iodine plus low vitamin A(HI+LVA) group, high iodine plus vitamin A1 (HI+VA1) group, high iodine plus vitamin A2(HI+VA2) group. The VA was given in food(4000,4000,0,0,8000,16 000 U/kg), and the iodine was given as potassium iodate in water (I-:50,3000,50,3000,3000,3000 μg/L). The apoptosis was tested using in situ end labehng(TUNEL) method. Reverse transcription polymerase chain reaction (RT-PCR) were used to measure the level of mRNA of apoptosis gene(Fas, FasL, Bcl-2) in tissues. Results Apoptotic index measured by TUNEL method was rising along with the mice age. Compared to NI group[(14.09±5.68)%], apoptotic index was significantly increased in HI[(20.91±9.57)%], HI+LVA[(20.29±9.90)%]and HI+VA2 [(19.51±8.25)%]groups in the three months(P < 0.05). Compared to NI group[(16.80±9.90)%], apoptotic index was significantly increased(P < 0.05) in HI[(23.22±8.58)%],LVA[(22.56±6.17)%],HI+LVA [(25.99±9.62)%],HI+VA1 [(21.65±7.74)%]groups in the six months. Compared with the NI group(Fas: 1.29±0.25,1.27±0.26; FasL: 1.60±0.13,1.65±0.13), the mRNA levels of Fas and FasL in HI group(Fas: 1.57±0.36,1.49±0.35; FasL: 1.85±0.46,1.84±0.32) were increased, but the differences were not remarkable(P > 0.05) in the three and six months. Compared with the HI group, the mRNA levels of Fas in HI+ VA1, HI+VA2(1.33±0.35, 1.30±0.26) groups were decreased to the level in NI group in the six months. The mRNA levels of Fas and FasL were not different (P > 0.05) between HI+LVA(I.60±0.27,1.88±0.46) and HI groups in the three months. The mRNA levels of Bcl-2 were not remarkably differences in the three months (1.05±0.19,0.96±0.33,0.95±0.26,1.18±0.27,1.10±0.19,0.98±0.36, all P > 0.05), and in the six months (1.35±0.28,1.60±0.25,1.48±0.18,1.71±0.26,1.66±0.29,1.56±0.35, all P > 0.05). Conclusions Excessive iodine can cause thyroid cells apoptosis in mice. Supplementation of suitable amount of VA can regulate the levels of the apoptosis-related genes expression, and partly antagonize the apoptosis caused by high iodine.
RESUMO
Objective In order to compare the iodine deficiency disorders(IDD)prevalent slatus in Chun'an County between 2006 and 2007,and to provide the science information for iodine supplementation in different regions.Methods Three schools of Wangzhai,Pingmen and Wenchang which the goiter prevalenee was the most severe were selected in Chun'an County;and from each school,90 pupils aged 8-10 years were randomly selected.B-ultrasound examination of thyroids,urine iodine and salt iodine were measured.Results The goiter rate in B-ultrasound were 7.5%(20/267),median of urine iodine was 247.5 μg/L,mean of salt iodine was 32.7 ms/ks in 2006;and the goiter rate in B-uhrasound were 3.7%(10/271),median of urine iodine was 383.4 μg/L,mean of salt iodine was 33.5 mg/kg in 2007.The goiter prevalence in Wangzhai,Pingrnen and Wenehang township were 15.2%(14/92),6.0%(5/83)and 2.2%(2/92),respectively,and median of urine iodine were 360.1.211.3,189.3μg/L,respectively,in 2006;The goiter prevalence were 6.6%(6/91),3.3%(3/90)and 1.1%(1/90),respectively.and median of urine iodine were 388.6,41 1.5,327.8μg/L,respectively,in 2007.Family ineome of Wangzhai,Pingmen and Wenchang township were 1000,2000,3000 yuan,respectively.Conclusions Goiter prevalence was correlated with urinary iodine,nutritional state and economic condition,high urinary iodine contents and poor nutritional status lcad to a high goiter rate.