Figure 1.
Grope the best concentrations of luteolin.
Different concentration of luteolin on the number of rod-shaped cells(%) (A), Release of LDH (B) and cardiomyocyte shortening amplitude (C) after I/R were detected. Each value represents the mean ± SEM, n = 6. *P<0.05,**P<0.01,***P<0.001 versus DMSO, #P<0.05, ##P<0.01 versus I/R. $P<0.05 versus Lut(2 µM)+I/R, &P<0.05 versusu Lut(4 µM)+I/R, %P<0.05 versusu Lut(8 µM)+I/R.
Table 1.
Each group of Myocardial Function in Isolated Ischemia/Reperfused hearts.
Figure 2.
Infarct size and LDH release quantity of each group.
Effects of luteolin and SP600125 on infarct size (A, B) and release of LDH (C) in isolated I/R hearts. The results are expressed as the mean ± SEM, n = 6. *P<0.05, **P<0.01 versus DMSO; #P<0.05 versus I/R; $P<0.05, versus I/R+Lut (40 µM), &&P<0.01, &P<0.05 versus I/R+Lut(40 µmol/L)+PD (20 µmol/L).
Figure 3.
Apoptosis of each group. A representative photomicrograph of a TUNEL (B) and DAPI-stained (A) cardiomyocytes were showed.
After 2-apoptotic effect of luteolin and SP600125 by TUNEL staining. The results are expressed as the mean ± SEM, n = 3. #P<0.05 versus I/R; $P<0.01 versus I/R+Lut (40 µM), &P<0.05 versus I/R+Lut(40 µmol/L)+PD (20 µmol/L). Cells were examined by light microscopy (200× magnification). Yellow allow indicate DAPI-stained nucleus, red allows indicate TUNEL-positive caryons.
Figure 4.
The contractile function of single cardiac cell. Effect of luteolin and SP600125 on shortening.
amplitude in isolated I/R cardiomyocytes were observered. The results are expressed as the mean ± SEM, n = 3. *P<0.05, **P<0.01 versus DMSO; #P<0.05 versus I/R; $P<0.05 versus I/R+Lut (8.0 µM), &P<0.05 versus I/R+Lut(8.0 µM)+PD(10 µM).
Figure 5.
The expression of p-ERK1/2, p-JNK, Bcl-2 and Bax.
The effects of luteolin and SP600125 on the expression of total ERK and p-ERK (A, B), Bcl-2 (C, D) total JNK and p-JNK (E, F), Bax (G, H). After 2 h reperfusion, the myocytes were harvested to detect protein expressions by western blot analysis. The results were expressed as the mean ± SEM. n = 3. **P<0.01 versus DMSO; #P<0.05, ##P<0.01 versus I/R; $P<0.05 versus I/R+Lut (8.0 µM), &P<0.05, &&P<0.01 versus I/R+Lut(8.0 µM)+PD(10 µM).
Figure 6.
The expression of p-PP1a, p-PLB and SERCA2a.
The effects of luteolin and SP600125 on the expression of total PP1a and phospho-PP1a (A, B), total PLB and phospho-PLB (C, D), SERCA (E, F). The results were expressed as the mean ± SEM, n = 3. *P<0.05,**P<0.01 versus DMSO; #P<0.05 versus I/R; $P<0.05 versus I/R+Lut (8.0 µM); &P<0.05 versus I/R+Lut(8.0 µM)+PD(10 µM).
Figure 7.
The possible mechanisms of luteolin exerting its protective effects on myocardium following I/R injury.
Pretreatment with luteolin and SP600125 can deregulate the expression of p-JNK, upregulate the expression of p-ERK following I/R, which can result in cells apoptosis were inhibited and contractile function of myocardium was improved. Pretreatment with luteolin can also decrease the expression of SERCA2a via ERK1/2-PP1a-PLB pathway. The effect of luteolin was almost completely abolished by pretreatment PD98059 before it.