Abstract： Objective To investigate the effect of granulocyte colony stimulating factor on cardiac function after heart operation in rat.Methods All 30 rats were randomly divided into control group,pretreatment group and pretreatment + intracardiac injection group(n =10 each group); each group underwent operation,including intravenous anesthesia with sodium pentobarbital,thoracotomy and incision on the left ventricle along the left anterior descending artery,then the incision was sutured immediately and the chest was closed.The surgical procedure without using G-CSF was completed in control group.G-CSF was injected by tail vein for 5 days before surgery in pretreatment group; in addition,G-CSF was injected directly around the ventricular incision during the surgery in pretreatment + intracardiac injection group.The cardiac structure and function of the rats after the treatments were assessed by echocardiography.Results Seven days after operation,echocardiography indicated that left ventricular ejection fraction (LVEF)and fractional shortening (FS)in control group were (52.8 ± 2.9)％,(22.2 ± 1.4)％ ; compared with the control group; LVEF and FS in pretreatment group [(56.5 ±4.3)％,(25.2 ±2.5)％,respectively] and pretreatment + intracardiac injection group [(61.2 ±3.6)％,(29.5 ±2.3)％,respectively] were improved,and there were significant differences among pretreatment group,pretreatment + intracardiac injection group and control group(all P ＜ 0.05).The left ventricular end-systolic dimension(LVESD)and left ventricular end-systolic volume (LVESV)in pretreatment group[(6.25 ± 0.92)mm,(0.57 ± 0.18)ml,respectively] and pretreatment + intracardiac injection group[(5.51 ± 0.85)mm,(0.44 ± 0.14)ml,respectively] 7 days after operation were lower than those in control group[(6.60 ±1.10)mm,(0.67 ± 0.31)ml,respectively],and the differences were significant (P ＜0.05); the LVESD and LVFSV in pretreatment + intracanliac injection group were lower than those in pretreatment group(P＜0.05).28 days after operation,LVEF and FS in pretreatment group[(59.6 ±4.7)％,(26.2±2.8)％,respectively] and pretreatment + intracardiac injection group [(63.8 ± 1.9)％,(30.9 ± 1.6)％,respectively] were higher than those in control group [(53.4 ± 3.6)％,(23.6 ± 1.7)％,respectively] (P ＜ 0.05),and the LVESD,left ventricular end-diastolic dimension,LVESV and left ventricular end-diastolic volume in pretreatment group[(5.92 ±0.72)mm,(7.48 ±0.61)mm,(0.49 ±0.14)ml,(1.05 ±0.25)ml,respectivel] and pretreatment + intracardiac injection group [(5.35 ± 0.54)mm,(7.26 ± 0.55)mm,(0.41 ± 0.08)ml,(1.02 ± 0.27)ml,respectively] decreased compared to those in control group [(6.98 ± 0.37)mm,(8.04 ± 0.42)mm,(0.76 ±0.15)ml,(1.37 ± 0.18)ml,respectively] (P ＜ 0.05).Conclusion Perioperative application of G-CSF can significantly improve systolic and diastolic functions in rat heart.