Relationship Between the Expression of c-fos Gene and Delayed Neuronal Death in the Neonatal Hippocampus Following Hypoxia-ischamia Insult

Objective To explore the relationship between the expression of c fos gene and delayed neuron death in perinatal hypoxia ischamia encephalopathy (HIE). Methods Terminal deo xynuleotidyl transferase mediated dUTP nick end labeling (TUNEL), immuno histochemistry andreverse transcription PCR(RT PCR) were used to detect the apoptosis and transcription and translation of c fos gene in the hippocampus following HIE. Results Positive signal of apoptosis from CA1 to CA4 sections were observed in experimental hippocampi. Marked signal appeared earlier and longer in CA1 section than in the other sections[CA1: 1 h: (14.6±2.3),24 h: (51±6),72 h: (17.4±0.3);CA4:1 h :1.3±1.6),24 h: (47±8),72 h: (21.6±0.6) apoptosis cell number/ mm 2 ],compared with the sham group of CA1 section P 0.01, CA1 and CA4 P 0.01. A positive ratio of c fos protein began to increase immediately and increased marked at the end of the 1st hour and reached a peak at the 2nd to 4 th hours in hippocampi following hypoxia(Hippocampus of every experimental group comparison to that of sham group was remarkably different P 0.05). The peak time of c fos mRNA expression was about 1 hour earlier than that of c fos protein in the hippocampus. c fos mRNA expression waw not detected in the hippocampus in the control group. The expression of c fos gene was almost in the CA4 and the cingulate sulcus neurons, apoptosis was almost observed in the CA1 neurons. Conclusion The transient expression of c fos gene might induce the cerebral cell apoptosis, which might have complex relationship with the delayed cell death.