Therapeutic Effect Of Adenovirus-mediated Hepatocyte Growth Factor Gene Transfer On Focal Cerebral Ischemia In Rats

Background: Cerebral ischemia is one of the diseases threatening human beings,and there are no effective methods to treat it. Hepatocyte growth factor(HGF) profoundly stimulates the growth of endothelial cells and angiogenesis in ischemic tissue,and acts as a survival factor for neurons in vitro. Recently, a novel therapeutic strategy for ischemic diseases using angiogenic growth factors or their genes to expedite and/or augment collateral blood vessel development has been proposed.Methods and Results: Replication-defective recombinant adenoviral vector carrying human HGF(Ad-HGF) was generated by homologous recombination in 293 cells. After infected by Ad-HGF, NIH3T3 cells expressed HGF. It was found that the transfecting rate of adenovirus vector carrying green fluorescence protein (GFP)to the primarily cultured neurons of newborn rat was high by flow cytometer. HGF was expressed in the primary nerve cells infected by Ad-HGF, and was a trophic factor to the neurons in serum-free medium. The distribution and persistence of adenoviral vectors were studied in a rat model of focal cerebral ischemia. It was demonstrated that the peak of GFP expression occurred on day 3 after administration from frozen sections. Green fluorescence decreased on day 7 and disappeared on day 14. The HGF levels of serum, homogenates of brain and other organs were examined by ELISA and immunohistochemistry. The results showed there was no significant difference between the test and control groups. The vascularity were evaluated through observing the paraffin-embeded slides stained with HE (hematoxylin-eosin). Angiogenesis was only observed in the test group on day 3. It was showed that the cerebral infarct volume was smaller obviously in the test group as compared with that in the control group by TTC staining. Expression of genes in the brain after focal cerebral ischemia and Ad-HGF injection was investigated using gene chips. It was found that 57 genes increased and 5 genes decreased in the ischemic group, and 43 genes increased and 32 genes decreased in the Ad-HGF injection group.Conclusion: Gene therapy of focal cerebral ischemia using HGF gene via the recombinant adenovirus vector is effective and relatively safe with regional administration.