Dynamic changes in the expression of bFGF and the FGF receptor following cerebral ischemia and reperfusion in the fetal rat

Song Weiwei , Han YK

No. 2 Hospital of China Medical University, Shenyang, China

Objective: Our purpose was to study the neurocyte responses of basic fibroblast growth factor and its receptor in the process of neuronal cell death during intrauterine ischemia and reperfusion.

Methods: Fetal rats with gestational age of 21 days were exposed to intrauterine ischemia by clamping the uterine blood supplying for 0, 15, 30, 45 and 60 minutes respectively. Other rats were reperfused for 1, 4, 8,15 and 24 hours after ischemia for 15 minutes. All of them would be killed at time points. Brains were removed for routine HE and immunohistochemical staining.

Results: bFGF was expressed in normal brain of 21-day fetal rat mainly in CA2 sub-field of hippocampus. Its receptor mainly existed in the endothelial cells of vessels. With the development of ischemia, some neurons in hippocampus and parasagital cortex exhibited degeneration and necrosis gradually without expression of bFGF in these cells, but it was really did in the neighboring intact cells in these areas. Reperfusion couldn’t save the degenerative cells but made the process developed further. Histological evaluation at 24 hours after reperfusion showed predominant apoptosis at hippocampus and some areas of cortex. Meanwhile, bFGF first intensively expressed at hippocampus, lately at parasagital cortex. However, bFGF receptors showed a delayed expression, no receptors could be found at those necrotic cells.

Conclusion: Our results suggest that augmentation of bFGF expression is related to the protective effects against cell damage following the ischemia or reperfusion, which suggests the neurotrophism of exogenously applied bFGF.

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