ABSTRACT
Oxidative stress can be regarded as an imbalance between the amount of reactive oxygen species (ROS) and the ability of a biological system to eliminate the toxic species and repair the resulting damages. Since the germinating seeds and the resulted seedlings are rich in enzymes, whereas the treatment with chemicals affects much the seed germination, producing also ROS, we evaluate here the influence of 2,4-dinitrophenol (DNP) and potassium iodate (KIO3) on wheat germination (Triticum aestivum L.) and seedlings growth. Germination rate, the masses and heights of the 7 day old seedlings, as well as the activity of some enzymes involved in the oxidative stress such as peroxidase, catalase and superoxide dismutase were measured seven days after the chemical treatment. The treatment of the wheat seeds with 10-5 - 10-3 M solutions of DNP resulted in a relative concentration-dependent inhibition of the germination, with a concomitant stimulation of the weight and height of viable seedlings. The Gasparom variety treated with 10-5 M KIO3 showed a slight increase in the germination rate in comparison with the control batch. The two tested substances determined a significantly modified response of the oxidative stress enzymes, especially in the seeds treated with 10-4 and 10-3 M solutions.
ABSTRACT
Objective To study the efficacy of L-3,5-diiodotyrosine (DIT) and inorganic iodine (KIO3) in iodine-deficiency Wistar rats.Methods Sixty Wistar rats,weighting about 160-180 g,were divided into two groups according to body weight by the random number table method:iodine-deficiency model (40 rats) was fed with low-iodine food (the iodine content was 35.9 μg/kg);optimal-iodine model (20 rats) was fed with low-iodine food and given with KIO3 water (the iodine content was 18 mg/L) 0.5 ml by intragastric once a day.Model was established for 3 months.Iodine-deficiency model was subdivided into low iodine (LI) group,KIO3 group and DIT group,eight,nine,ten rats in each group;from optimal-iodine model,nine rats were randomly selected as optimal iodine (NI) group.LI group was fed with low-iodine food;KIO3 group was fed with low-iodine food and given with KIO3 water (the iodine content was 18 mg/L) 0.5 ml by intragastric once a day;DIT group was fed with low-iodine food and given with DIT water (the iodine content was 18 mg/L) 0.5 ml by intragastric once a day;NI group was fed with low-iodine food and given with KIO3 water (the iodine content was 18 mg/L) 0.5 ml by intragastric once a day.After 3 months,24-hour urine of the rats was collected.According to the method for determination of iodine in urine by As3 +-Ce4+ catalytic spectrophotometry (WS/T 107-2006),iodine content in urine was detected.Rats were anesthetized intraperitoneally with 25％ urethane,blood from abdominal aortic was collected to determinate the serum thyroid hormone [total triiodothyronine (TT3),total thyroxine (TT4),free triiodothyronine (FT3),free thyroxine (FT4)] level in rats by automatic electrochemical luminescence immunoassay.All the rats were sacrificed to analyze the thyroid weight.Results ① The urine iodine showed significant differences in the four groups (x2 =25.24,P ＜ 0.05).The median of urine iodine concentration in the LI,NI,KIO3 and DIT groups were 3.00,286.14,223.37,214.33 μg/L,respectively.The urine iodine concentration in LI group was significantly lower than those of other three groups (all P ＜ 0.05).② The serum TT3,TT4,FT3,FT4 levels showed significant differences in the four groups (F =63.48,140.73,130.20,365.27,all P ＜ 0.05).And the hormone levels in KIO3 group were lower than those of the DIT group [TT3:(1.57 ± 0.20) vs.(1.97 ± 0.18) mmol/L,TT4:(51.23 ± 4.90) vs.(71.94 ± 5.27) mmol/L,FT3:(5.34 ± 0.45) vs.(6.98 ± 0.33) pmol/L,FT4:(26.18 ± 2.30) vs.(35.47 ± 2.28) pmol/L,all P ＜ 0.05].③The color of thyroid in KIO3 and DIT groups became pale pink.The absolute and relative thyroid weight showed significant differences in the four groups (F =225.05,345.40,all P ＜ 0.05).The absolute thyroid weight [(31.76 ± 1.75) mg] and relative thyroid weight [(11.69 ± 3.47) mg/100 g] in DIT group was lower than that of the KIO3 group [(36.31 ± 5.23) mg,(12.83 ± 4.38) mg/100 g,all P ＜ 0.05].Conclusion Animal experimental results show that DIT has a better iodine-supplementing efficacy than that of KIO3.