| Part I Model of myocardial infarction and influence on cytokine by G-CSF treatment in rabbitsChapter I Setting up myocardial infarction modelObjective:To set up a model of myocardial infarction in rabbits.Methods:Under anesthesia and mechanical ventilation with room air, a left thoracotomy was performed;4-0silk string was placed the left branch of coronary arterial.we decide whether the model success by ST section raising0.2mv in ECG.38Healthy New Zealand white rabbits were divided into two groups after myocardial infarction model:G-CSF group and control group.10μg/kg/d G-CSF in G-CSF group and0.5ml/kg/d saline in control group was given at24hours after myocardial infarction (MI)one time per day for5days.Results:we successfully set up MI model in38Healthy New Zealand rabbits. But one was died because of diarrhea.Conclusion:we can make up the stable myocardial infarction model by ligation of left anterior descending artery. Chapter II The change of Peripheral blood cells and cytokines by G-CSF treatment after myocardial infarction in rabbitsObjective:To find out the change of peripheral blood cells and inflammatory cytokines by G-CSF traetment in myocardial infarction rabbits.Methods:we collect respectively0.5ml and1.5ml vein blood through ear vein of rabbits before and at7days,14days post myocardial infarction in two groups (G-CSF group and control group).Blood cell counters was read by blood cell automatic analyzer.TNF-a and HsCRP was measured by ELISA double-antibody sandwich methods. Results:1. Peripheral blood cell counts:In the G-CSF group, White blood cells, Granulocytes, Monocytes increased from6.12±0.27*109/L,4.20±0.20*109/L,0.39±0.07*109/L before MI to11.30±4.83*109/L,8.44±2.9*109/L,1.20±0.91*109/L at7days after MI and restored to8.31±2.50*109/L,6.07±1.80*109/L,0.49±0.20*109/L at14days after MI (p<0.05) respectively; Red blood cells was slight dropped in,Lymphocytes and thrombocytes was slight increased at7days after MI than that before MI(p>0.05). In control group, White blood cells,Monocytes increased from6.32±0.31*109/L,0.42±0.03*109/L before MI to6.86±0.67*109/L,0.49±0.17*109/L at7days after MI (p<0.05)and granulocytes increased from4.40±0.35*109/L before MI to4.60±0.20*109/L at7days after MI(p>0.05). White blood cells, granulocytes, monocytes restored to6.36±2.50*109/L,4.32±0.67*109/L,0.40±0.11*109/L at14days after MI respectively(p>0.05), Red blood cells was slight dropped in, lymphocytes was slight increased at7days after MI than that before MI(p>0.05). Between two group, White blood cells, Granulocytes, Monocytes had a significant increased in G-CSF group than that in control group(p<0.05) at7days after MI. there had the similarly rule in two group at14days after MI,but both of them has dropped than it at7days after MI (p<0.05).2. The change of cytokine:①HsCRP:In G-CSF group:HsCRP increased from (1.22±0.36)ug/mL before MI to (7.32±2.32)ug/mLat7days after MI (p<0.05) and restored to(2.02±1.57)ug/mL at14days after MI(p<0.05).In control group:HsCRP increased from (1.30±0.22) ug/mLbefore MI to (6.53±1.21)ug/mLat7days after MI (p<0.05) and restored to (4.12±0.68)ug/mLat14days after MI (P<0.05); However comparision in two groups, HsCRP in G-CSF group is higher than that in control group, but had no significant difference at7days after MI(p>0.05).HsCRP restored but no arrived normal in two groups at14days after MI,but there had significantly descend in G-CSF group than that in control group (P<0.05)。(2)TNF-a:TNF-α increased from (46.1±22.4)pg/mL before MI to(80.1±40.1)pg/mL at7days after MI (p<0.05) and restored to (40.9±17.7)pg/mL at14days after MI in G-CSF group.It increased from (42.3±16.3)pg/mL before MI to (74.4±39.1) pg/ml at7days after MI (p<0.05) and restored to(53.2±14.8)pg/mL atl4days after MI in control group (P<0.05);However comparision in two groups, TNF-α in G-CSF group is higher than that in control group, but has no significant difference at7days after MI (p>0.05). It restored in two groups at14days after MI,Moreover,there had significantly descend in G-CSF group than that in control group (P<0.05)Conclusion:G-CSF can increase the number of white blood cells and rstore inflamation cytokine early.It is benefit to the phagocytosis of necrotic tissue and repair in the acute myocardial phase. Part II Influence on cardiac function by G-CSF treatment after myocardial infarction in rabbitsObjective:To investigate the influence on cardiac function by G-CSF treatment after myocardial infarction in rabbits.Methods:We measured left ventricular ejection fraction(LVEF), fractional shortening(FS), left ventricular end systolic diameter(LVESD), left ventricular end diastolic diameter (LVEDD),left atrial diameter(LAD),left ventricular posterior wall thickness(LVPWT),interventricular septal thickness(IVST)by using two-dimensional ultrasound atlOdays and60days after MI and before MI. Brain natriuretic peptide was measured by ELISA double-antibody sandwich methods.Results:1. there had no difference in LVEF. FS. LVESD. LVEDD. LAD. LVPWT、 IVST in two groups before MI. At10days after MI,the result of G-CSF and control group are (70.3±9.4)%via (58.2±13.7)%for LVEF (p<0.05);(39.2±6.4)%via (28.7±11.1)%for FS(p<0.05),(7.1±1.8)mm via (10.2±2.1)mm for LVESD(p<0.05),(2.83±0.04)mm via (3.01±0.63)mm for LVPWT (p<0.05),(2.67±0.17)mm via (2.79±0.18)mm for IVST(P<0.05),LVEDD has no signifancantly different in two groups. At60days after MI,In G-CSF group:LVEF:(73.6±3.7)%. FS:(43.5±3.7)%. LVESD:(7.9±0.3)mm. LVEDD:(14.1±0.8)mm. LAD:(7.14±0.24)mm. LVPWT (2.98±0.25)mm、IVST:(2.91±0.19)mm respectively;but in control group LVEF:(60.1±12.0)%、FS:(33.1±9.29)%、LVESD:(10.1±1.6)mm、LVEDD:(15.1±1.0) mm、 LAD:(8.90±0.91) mm、LVPWT:(3.37±0.44) mm、IVST:(0.28±0.42) mm, Excepting the number of LVEDD, Each of number has significant difference between two group(p<0.01).2. Brain natriuretic peptide(BNP):The level of BNP has no difference in two groups before MI,But it increased to the top at2hours after MI, There has no significant difference between two groups(P>0.05).At10days after MI, the result of G-CSF and control group are (113.38±39.40)pg/mL via (325.35±96.14) pg/mL(P<0.01).At60days after MI, the number in two groups has significantly decreased:it is (34.90±19.90) pg/mL via (150.14±37.15)pg/mL (p<0.01). Moreover,the level of BNP was close to it before MI in G-CSF group,but it kept unnormal in control group(P<0.01).Conclusion:G-CSF can improve heart function and reduce heart remodeling after MI. Part Ⅲ Influence on action potential duration and transmural repolarization dispersion in different regions by G-CSF treatment after myocardial infarction in rabbits.Objective:To investigate the influence on action potential duration(APD) and transmural repolarization dispersion(TDR) in different regions and the change of ventricular fibrillation threshold(VFT) by G-CSF treatment after MI and before MI in rabbits.Methods:Under anesthesia and mechanical ventilation with room air, A left thoracotomy was performed again at7days、14days、30days、60days after MI. Defined3mm bottom left side of ligation points as MI zone、the lower left of MI border3mm as infarcted border zone、upperleft3mm of ligation of as surrounding zone respectively.Reversible inhibited sinus node by0.1～0.3mL10%formaldehyde.Bipolar pacing electrode was fixed high right atrial (pacing the circumference of200ms).APD5o,APD90was recorded in different zones.APD50was defined as the origination of APD to repolarization50%, APD90was defined as the origination of APD to repolarization90%。TDR90was defined as the difference of the longest and shortest in three myocardial layers. In infarcted border zone, short and high strength stimulate was given discontinuously, the minimum output voltage for inducing ventricular fibrillation was defined VFT. Results: APD in midmyocardium, At30minutes after MI, APD50was decreased by about45-50%in infract zone, about35%infracted border zone,about25%in surrounding zone in two groups respectively. there had no significnet difference between two groups(p>0.05), APD90had the same rules. At7days after MI,APD50in G-CSF group and control was (86.2±3.6)ms via (78.5±5.2)ms (P>0.05) in infract zone,(106.9±3.9)ms via (89.2±2.1)ms (P<0.05)in infracted border zone,(108.2±6.3)ms via (95.1±4.2)ms(P<0.05) in srrounding zone, APD90in G-CSF group and control was(102.2±3.6) ms via(95.3±5.4)ms (P<0.05) in infract zone,(120.3±3.9) ras via (107.4±4.4) ms (P<0.05)in infracted border zone,(131.2±6.7) ms via (117.5±4.2)ms(P<0.05) in srrounding zone, Compared with it at30min, All of them recovered in different zone. At14days after MI, APD50in G-CSF group and control was(95.2±4.7)ms via(83.1±3.5)ms (P<0.05) in infract zone,(114.1±3.3)ms via(93.2±4.6)ms (P<0.05)in infracted border zone,(116.1±5.3)ms via (98.2±4.5)ms (P<0.05) in srrounding zone, APD90in G-CSF group and control was(114.0±5.9) ms via(102.3±4.8)ms (P<0.05) in infract zone,(135.9±3.3)ms via (112.0±4.6)ms (P<0.05)in infracted border zone,(140.3±6.4)ms via (120.2±4.5)ms(PO.05) in srrounding zone, Compared with it at7days, All of them recovered in different zone. At30days after MI, APD50in G-CSF group and control was (98.2±7.1) ms via (84.1±3.2)ms (P<0.05) in infract zone,(116.4±2.9)ms via (98.6±3.5)ms (P<0.05)in infracted border zone,(117.1±3.9)ms via (109.3±4.7)ms(PO.05) in srrounding zone, APD90in G-CSF group and control was (120.4±3.8)ms via (112.1±5.5)ms (P<0.05)in infract zone,(140.4±4.7)ms via (120.3±7.1)ms (PO.05)in infracted border zone,(141.4±2.6)ms via (128.1±3.3)ms (P<0.05) in srrounding zone, Compared with it at14days, it recovered in infract zone. At60days after MI, APD50in G-CSF group and control was (103.9±4.8)ms via (99.2±5.7)ms (P>0.05) in infract zone,(116.2±4.0)ms via (118.2±2.6)ms (P>0.05)in infracted border zone,(116.8±2.9)ms via (118.6±3.9)ms (P>0.05) in srrounding zone. APD90in G-CSF group and control was (125.0±4.4)ms via(119.0±6.7)ms (P>0.05) in infract zone,(140.5±2.1)ms via (140.0±2.8)ms (P>0.05)in infracted border zone,(141.4±3.7)ms via145.3±4.0ms (P>0.05) in srrounding zone, Compared with it at30min, All of them recovered in different zone with the extension of time.No matter in subendocardium,midmyocardium or in subepicaedium at30min after MI, But APD50、APD90were decreased and shorten the largest in midmyocardium.With time increases, APD become prolongation in midmyocardium. In infracted border zone,TDR reduced in G-CSF group [(14.7±5.1)ms] than it in control group[(26.5±6.1) ms]at7days after MI, Further shortened to (6.4±2.1)ms, compared it in the control group [(23.6±7.9)ms] at14days after MI.It had significant difference(p<0.05) in two groups.In infracted border zone, Ventricular fibrillation threshold has increased in G-CSF group [(18.2±2.9)V]than it in control group[(14.6±1.5) V],P<0.05.Conclusion:G-CSF can promote the recovery of action potential, prolong the APD in midmyocardium to reduce TDR, and improve VFT.It can reduce the incidence of ventricular arrhythmias. |
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