Objective To study the mechanism of injury of cortical nerve cell in the newborn with hypoxia/ischemia brain damage (HIBD),
and the neuroprotective effect of
Radix Astragali (RA). Methods Neonatal HIBD model rats were established and divided into the sham group, the model group and the RA group. Brain of rats obtained at different time points after HIBD to conduct histopathological examination, neuron death rate count, as well as determination of caspase 3 (cysteinyl aspartate specific proteinase 3) protein mRNA
expression in cerebral cortex by immunohistochemistry, semi quantitative reverse transcription polymerase chain reaction (RT PCR) respectively. Results In the model group, caspase 3 mRNA and protein showed an increase at 6 hrs, reached the peak at 24 hrs, and decreased at 48 hrs after HIBD, on the 5th and 7th day restored to baseline level. After being treated by RA, the neuron death rate of ligated side was obviously reduced, caspase 3 mRNA and protein expression peak value decreased by 45% (mRNA) and 40%-43% (protein). Conclusion RA shows markedly neuron protection in immature brain cortex after HIBD, which is related with the inhibition on caspase 3 expression.