RESUMO
Objective To observe the mRNA and protein expression of thyroglobulin (Tg) and thyroid peroxidase (TPO) in each trimester of pregnant and lactating Wistar rats.Methods Ninety-six SPFNAF Wistar rats (84 female and 12 male),weighting 220-260 g were involved.All female Wistar rats were randomly divided into 7 groups according to their body mass via the random number table method:control group,early pregnancy group (7 d),midpregnancy group (14 d),late pregnancy group (21 d),early lactation group (7 d),midlactation group (14 d) and late lactation group (21 d),12 rats in each group.The rats were fed with conventional feed and drank deionized water freely.Female rats of the last 6 groups were mated with male rats.Thyroids were collected on the 7 d,14 d and 21 d of their pregnancy and lactation,respectively.The mRNA expression levels of Tg and TPO were detected by quantitative real-time PCR,and the protein expression levels of Tg and TPO were detected by Western blotting.Results The expression levels of Tg mRNA in thyroid tissue in the control group,early,middle and late pregnancy and early,middle and late lactation (1.05 ± 0.01,3.20 ± 0.23,1.88 ± 0.12,2.69 ± 0.20,1.53 ± 0.19,2.37 ± 0.31,2.23 ± 0.12) were significantly different between groups (F =42.864,P ＜ 0.05),and those of pregnancy and lactation groups were higher than those in the control group (P ＜ 0.05).The expression levels of Tg protein were 0.15 ± 0.01,0.38 ± 0.01,0.32 ± 0.02,0.37 ± 0.01,0.21 ± 0.01,0.35 ± 0.01,0.44 ± 0.01,respectively.The differences between groups were statistically significant (F =232.250,P ＜ 0.05).And those of pregnancy and lactation groups were higher than those in the control group (P ＜ 0.05).The expression levels of TPO mRNA in thyroid tissue in the control group,early,middle and late pregnancy and early,middle and late lactation (0.57 ± 0.01,0.74 ± 0.03,0.78 ± 0.13,1.08 ± 0.10,0.98 ± 0.10,1.00 ± 0.07,0.76 ± 0.05) were significantly different between groups (F =15.448,P ＜ 0.05).And those of pregnancy and lactation groups were higher than those in the control group (P ＜ 0.05).The expression of TPO protein were 0.23 ± 0.01,0.41 ± 0.01,0.72 ± 0.02,0.78 ± 0.01,0.49 ± 0.01,0.52 ± 0.01,0.45 ± 0.02,respectively.The differences between groups were statistically significant (F =563.692,P ＜ 0.05).And those of pregnancy and lactation groups were higher than those in the control group (P ＜ 0.05).Conclusions The mRNA and protein expression levels of TPO and Tg have increased in pregnant and lactating rats.This performance may be raleted to thyroid hormone deficiency and mild hypothyroidism.