[Study on the expression and the role of macrophage migration inhibitory factor in the brain of neonatal rats with hypoxia-ischemia brain damage].

OBJECTIVE

To explore the expression of macrophage migration inhibitory factor (MIF), phosphorylated extracellular signal regulated kinases 1/2 (pERK1/2), matrix metalloproteinase-9 (MMP-9) in brain and the correlations with cerebral edema after hypoxia-ischemia brain damage (HIBD).

METHODS

144 seven-day-old SD rats were randomly dividend into three groups that was the sham operation group, HIBD group and intervention group with anti-MIF. Each group were executed in 1 h, 6 h, 12 h and 24 h, 3 d, and 7 d. The expression of MIF, MMP-9 protein in the right cerebral cortex was detected with immunohistochemistry methods, the relative content of pERK1/2 was detected with Western blot and the water content of brain was evaluated with dry-wet method.

RESULTS

Comparing with the sham group the expression of MIF in the HIBD group began to increase on 1 h, and peaked on 24 h (P < 0.05), and MMP-9 began to express on 6 h, and also peaked on 24 h (P < 0.05), while pERK1/2 expressed rapidly to peak on 1 h, and quickly decreased on 6 h, and began to increase on 12 h and reached the peak again on 24 h (P < 0.05). Being treated with hypoxia-ischemia, the water content of brain began to increase on 6 h and peaked on 3 d (P < 0.05). And comparing with HIBD group, the expressions of MIF, pERK1/2, MMP-9 and the water contents were decreased obviously in the anti-MIF group (P < 0.05).

CONCLUSION

The increased expression of MIF in the neonatal rats with hypoxia-ischemia brain damage maybe via activing the ERK1/2 ways to induce MMP-9 expressand leading to cerebral edema.