Objectives To investigate PARP1 impacts on the protein expression and changes in activity of rat hearts in ischaemia-reperfusion injury. Research the tumour necrosis factor-a (TNF-a), Interleukin-6 (IL-6) of rat heart ischaemic/reperfusion on the same period, and study these serum cyokines expression and infarction area after PARP1 was inhibited by its inhibitor 3-aminobenzamid (3-AB).
Methods The rats (n=190) were randomly divided into sham group, ischaemia/reperfusion, Immunohistochemistry was used to examine the PARP1 expression at 15 min, 30 min, 1 h, 2 h, 4 h, 6 h, 24 h. TNF-a, IL-6 levels of serum and myocardial tissue were detected by ELISA. PARP inhibitor 3-AB and the equal volume of saline were given to sham group and PARP1-3AB group at 30 min after thoracotomy and 1 h after administration of reperfusion respectively, then testing the infarction area.
Results 1. The average optical density values on expression of PARP-1 of I/R reperfusion group at different time points (15 min, 30 min, 1 h, 2 h, 4 h, 6 h, 24 h) were 176.81±6.47, 181.07±7.58, 190.15±9.09, 208.02±16.04, 197.96±13.80, 195.31±8.65, 190.35±5.53, compared with sham group were significantly different (p<0.05).
2. At different time points, the content of TNF-a (18.05±2.49, 20.95±2.48, 32.96±2.85, 40.53±3.09, 39.07±2.41, 19.15±2.29, 38.81±2.56 pg/mg) and IL-6 (17.1±2.7, 20.8±3.5, 33.8±3.9, 39.0±3.9, 38.2±4.5, 19.1±2.1, 22.1±3.5 pg/mg) in the myocardium were all obviously expressed, compared with control group had significant difference (p<0.05).
3. At different time points, the content of TNF-a (18.05±2.49, 20.95±2.48, 32.96±2.85, 40.53±3.09, 39.07±2.41, 19.15±2.29, 38.81±2.56 pg/mg) and IL-6 (17.1±2.7, 20.8±3.5, 33.8±3.9, 39.0±3.9, 38.2±4.5, 19.1±2.1, 22.1±3.5 pg/mg) in the serum had significant difference compared with control group (p<0.05).
4. Left ventricular myocardial infarction area of I/R ischaemia 45 min, 2 H reperfusion group was 33.24±3.78%, compared with PARP-3AB group (20.02±2.12%) was higher (p<0.05).
Conclusions 1. The level of PARP1 of ischaemia-reperfusion myocardial and related cytokines IL-6, TNF-a were showed dynamic changes, reperfusion during 15 min to 2 H was gradually increasing, during 4 H to 6 H was gradually decline, at 24 H a slightly elevated.
2. PARP1-3AB inhibited the activity of PARP1 and the expression of cytokines.
3. It is important to apply PARP inhibitors in ischaemia-reperfusion early phase. PARP reduced infarct size.