Objective To observe the expression of hypoxia-inducible factor 1α(HIF-1α) in rat brain after hypoxia-ischemia brain damage (HIBD) and L-thyroxine (L-T4) of different dose treated. Methods Eighty postnatal 7 days old Sprague-Dawley(SD) rats were randomly divided into 5 groups :the sham operation group, hypoxia-ischemia group (HI), menstruum-treated group, L-T4-treated groups of low and high dose.The rats of menstruum-treated, L-T4-treated groups of low and high dose were respectively daily administrated of intraperitoneal injection of menstruum of the equal volume and 2 μg/100 g L-T4, 3.5 μg/100 g, once a day, for 5 days.The expression of HIF-1α were detected by immunohistochemistry.Reverse transcription-polymerase chain reaction(RT-PCR) was used to detect the level of HIF-1α mRNA. Results Compared with the sham operation group, the levels of HIF-1α protein(38.581±2.846) and HIF-1α mRNA(0.174±0.015) were upregulated in HI group(72.795±6.121, 0.448±0.035 respectively), as well as in menstruum-treated group.The levels of HIF-1α protein (117.350±9.374, 142.842±8.948 respectively)and HIF-1α mRNA(0.618±0.042, 0.711±0.049 respectively) in L-T4-treated groups of low and high dose were higher than HI group(P<0.05).The influence of L-T4 on HIF-1α protein and HIF-1α mRNA was dose dependent, namely with the increase of dose, their expression increased (P<0.05). Conclusion L-T4 upregulats HIF-1α mRNA and protein expression in neonatal rats with HIBD.
Key words
hypoxia-inducible factor 1α /
L-thyroxine /
hypoxia-ischemia brain damage /
neonatal rat
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