OBJECTIVE:To study the effects of ligustrazine on the SCGRP and on the expression of CGRP,PDGF and bFGF in the lung of CHPH rats.METHOD:A stable rat modle of CHPH was established.The serum CGRP levels were mesured by enzyme immunoassay.The expression of CGRP,PDGF and bFGF in lumg were observed by immunohistochemical method.RESULTS:①The SCGRP level of H group was significantly lower than that of N group (P＜0.01) but no difference between the H+Li group and H group (P＞0.05).②The expression of CGRP,PDGF and bFGF increased obviously in lung tissue of H group,whereas the expression of bFGF and PDGF of H+Li group reduced obviously but that of CGRP was not influenced.CONCLUSION:SCGRP reduction and expression increasion increasion of PDGF.bFGF have close relation with the formation of CHPH;Inhibiting the expression of PDGF.bFGF may be an aspect of the mechanism of preventing and treating HPH by ligustrazine.