ABSTRACT
Objective To explore the effects of thyroid hormone on the expression of homeobox gene Nkx6.1 in offspring of hypothyroidism rats and the relationship between gene expression and hormone level by supplying their hypothyroidism pregnant mother with thyroid hormone. Method A total of 240 Wistar rats were half nude and half female. Female rats were randomly divided into eight groups: control, hypothyroidism group, hypothyroidism groups which were supplied with thyroid hormone in high, medium and low dosage in early stage(1- 17 d) and in late stage( 18 - 20 d). According to 100 grams of body weight, the concentration of thyroid hormone were 3.5,2.0,0.5 μg/d in high, medium and low dosage group. All the rats were fed with low-iodine food. The normal control group was given KIO_3 solution and the other groups were given deionized water. After three months female rats were mated with male rats. The content of Nkx6.1 mRNA in brain tissue of 17-day fetal rats, new-born and 20- day old offspring by real-time fluorescence quantitative PCR techniques. Results①A rat model of hypothyroidism was successfully established, there were statistical significance between 8 groups in TT_3,TT_4,FT_3,FT_4(F=4.08,31.99,5.79,26.34, all P < 0.01 ). ② The expression of Nkx6.1 mRNA had significant difference(F = 758.720, 1121.589,144.716, all P < 0.01 ) between groups in 17-day fetal rats, new-bern and 20-day old offsprings and intra- groups in different time (F=2898.863,325.605,716.285,56.329,236.727,196.678,7115.752,9152.306, all P < 0.01 ). ③The time factor and dosage factor had influence on Nkx6.1 mRNA expression(F = 1176.655,246.530, all P < 0.01 ). There were interaction between time and dosage factor(F = 1249.934, P < 0.01 ). ④Comparison of Nkx6.1 mRNA expression between hypothyroidism group and normal control group had significant difference in the above three time points(all P < 0.01 ). ⑤Comparisons of Nkx6.1 mRNA expression between 6 hypothyroidism groups which were supplied with thyroid hormone and hypothyroidism group had significant difference(all P < 0.01 ) in new-bern and 20-day old offspring; comparisons of Nkx6.1 mRNA expression between hypothyroidism groups which were supplied with high and medium thyroid hormone and hypothyroidism group had significant difference in 17-day fetal rats(all P < 0.01 ). ⑥Comparison of Nkx6.1 mRNA expression between hypothyroidism groups which were supplied with medium thyroid hormone in early stage and normal control group had no statistical significance (all P > 0.05), while between the other 5 groups which were supplied with thyroid hormone and normal control group had significant difference(all P < 0.01 ) in the above three time points.⑦Multiple comparison of early stage groups which were supplied with thyroid hormone showed that the expression of Nkx6.1 mRNA had significant difference(all P < 0.01) between high, low dosage groups and medium group in 17-day fetal rats, new-bern and 20-day offspring(all P< 0.01). ⑧Multiple comparison of late stage groups supplied with thyroid hormone showed that old offspring and between high dosage groups and low dosage groups in 17-day fetal rats and 20-day the expression of Nkx6.1 mRNA had significant difference(all P < 0.01 ) between three groups in new-bern and 20- day old offspring. Conclusion The expression of Nkx6.1 in rats offspring is highly related to the supply dosage and supply time of thyroid hormone in hypothyroidism pregnant rats.
ABSTRACT
<p><b>OBJECTIVE</b>To explore the effects of thyroid hormone on the expression of homeobox gene Nkx2.1 mRNA in child rat by supplying their hypothyroidism pregnant mother with different dose of levothyroxine (L-thyroxine, L-T(4)) in different times.</p><p><b>METHODS</b>120 female Wistar rats were randomly divided into eight groups according to the body weight: control group, non-treatment hypothyroidism group, hypothyroidism groups supplied with L-T(4) in high, medium and low dosage in early stage (1st-17th day of pregnancy) and in late stage (18th day of pregnancy-20th day after childbirth). According to 100 grams of body weight, the concentrations of L-T(4) were 3.5, 2.0, 0.5 µg/d in high, medium and low dosage group. All the rats were fed with low-iodine food. The control group was given 200 µg/L potassium iodate solution as drinking water and the other groups were given deionized water. After three months, the rats were mated with normal male rats. After the pregnancy was confirmed, hypothyroidism groups were supplied with L-T(4) of different concentrations. Brain samples were taken from the 17-day fetal rats, new-born and 20-day old offsprings and the levels of Nkx2.1 mRNA in brain tissue were analyzed by real-time fluorescence quantitative PCR techniques.</p><p><b>RESULTS</b>The levels of TT(3) in hypothyroidism groups supplied with L-T(4) in high, medium and low dosages in early and late pregnant stages, non-treatment hypothyroidism group and control group were (0.85 ± 0.17), (0.81 ± 0.18), (0.86 ± 0.21), (0.85 ± 0.20), (0.89 ± 0.18), (0.85 ± 0.20), (0.86 ± 0.20), (1.08 ± 0.07) nmol/L (F = 4.08, P < 0.01); the levels of TT(4) in each group were (0.43 ± 0.16), (0.39 ± 0.11), (0.39 ± 0.13), (0.43 ± 0.17), (0.51 ± 0.19), (0.43 ± 0.16), (0.41 ± 0.15), (39.43 ± 14.16) nmol/L (F = 31.99, P < 0.01); the levels of FT(3) in each group were (3.29 ± 0.61), (3.29 ± 0.61), (3.24 ± 0.61), (3.28 ± 0.63), (3.31 ± 0.59), (3.28 ± 0.50), (3.24 ± 0.49), (4.93 ± 0.46) pmol/L (F = 5.79, P < 0.01); the levels of FT(4) in each group were (3.38 ± 0.80), (3.31 ± 0.67), (3.29 ± 0.73), (3.27 ± 0.71), (3.48 ± 0.81), (3.56 ± 0.66), (3.29 ± 0.61), (27.29 ± 4.53) pmol/L (F = 26.34, P < 0.01). The expression of Nkx2.1 mRNA in non-treatment hypothyroidism group (9.15 × 10(-5) ± 9.17 × 10(-5)) was lower than control group (65.1 × 10(-5) ± 40.90 × 10(-5)) in 17th day of pregnancy (t = 66.224, P < 0.05); the expression of Nkx2.1 mRNA in non-treatment hypothyroidism group (3.16 × 10(-5) ± 0.142 × 10(-5)) was lower than control group (55.6 × 10(-5) ± 51.05 × 10(-5)) in new-born (t = 102.225, P < 0.05); the expression of Nkx2.1 mRNA in non-treatment hypothyroidism group (8.09 × 10(-5) ± 8.21 × 10(-5)) was lower than control group (13.9 × 10(-5) ± 7.43 × 10(-5)) in 20th day after birth (t = 9.235, P < 0.05). The trend of Nkx2.1 mRNA in hypothyroidism groups was decreased in group supplied with L-T(4) in medium dosage in early stage descends in 17th day of pregnancy, new-born and 20th day after birth (57.1 × 10(-5) ± 22.90 × 10(-5)), (30.8 × 10(-5) ± 27.20 × 10(-5)), (17.1 × 10(-5) ± 0.623 × 10(-5)) (F = 13.394, P < 0.01). The expression of Nkx2.1 mRNA in hypothyroidism groups supplied with L-T(4) in medium dosage in early stage in 17th day of pregnancy, new-born and 20th day after childbirth was closest to the control group in every period (t values were 0.225, 0.336, 0.345, all P values > 0.05).</p><p><b>CONCLUSION</b>The difference in the expression of homeobox gene Nkx2.1 mRNA is highly related to the level of thyroid hormone.</p>
Subject(s)
Animals , Female , Pregnancy , Rats , Animals, Newborn , Genetics , Metabolism , Brain , Metabolism , Hypothyroidism , Drug Therapy , Nuclear Proteins , Genetics , Pregnancy, Animal , RNA, Messenger , Genetics , Rats, Wistar , Thyroid Nuclear Factor 1 , Thyroxine , Pharmacology , Transcription Factors , GeneticsABSTRACT
Objective To investigate the effects of lipopolysaccharide(LPS) on the expression of hypoxia inducible factor-1?(HIF-1?) and its target gene glucose transpoter-1(GLUT-1)in human monocyte lines THP-1. Methods THP-1 cells were stimulated with 1 ?g/mL LPS for 0,2,4,6 or 8 h.The expression of HIF-1? protein of THP-1 cells was detected by Western blotting,and RT-PCR was employed to detect the expression of HIF-1? mRNA and GLUT-1 mRNA.THP-1 cells were exposed to different concentrations of LPS(0,0.01,0.1 and 1 ?g/mL) for 6 h,and the expression of HIF-1? protein of THP-1 cells was detected by Western blotting. Results The expression of HIF-1? protein of THP-1 cells began to increase 2 h after being treated with 1?g/mL LPS,significantly increased after exposure for 4 h(P