The general condition of rats in each group
Compared with the control group, the food and water intake of rats in the model group were decreased, the increase of weight was slow, and the response was weakened. Compared with the model group, the food and water intake of rats in propranolol group were increased, the increase of quality was stable, and the reaction ability was enhanced. None of the rats in the control group or the propranolol group died, while three rats in the model group died
Comparison of HW/BW in the rats in each group
Compared with control group, the HW/BW ratio in the model group was significantly increased (P<0.01). Compared with model group, the HW/BW ratios in the propranolol group were significantly decreased (P<0.01) (Table 1).
Table 1 The effect of propranolol on HW/BW of rats among groups
group
|
BW
|
HW
|
HW/BW
|
Control
|
221.90±15.67
|
0.774±0.069
|
0.349±0.020
|
Model
|
222.86±14.84
|
1.130±0.104***
|
0.506±0.015***
|
Propranolol
|
229.30±12.04
|
0.973±0.044###
|
0.425±0.014###
|
Data are presented as mean ± SD.***P<0.01, statistical comparison between control group and model group; ###P<0.01, statistical comparison between propranolol group and model group.
Comparison of VA incidence in the rats in each group
Compared with control group, the VT and VP incidence in the model group was significantly increased(P<0.01). Compared with model group, the incidence in the propranolol group was significantly decreased(P<0.05)(Fig 1).
Fig1 Comparison of ventricular arrhythmia in rats in each group The electrocardiogram of rats in control group was normal. The electrocardiogram of rats in model group showed mainly NSVT and SVT. Electrocardiogram of rats in propranolol group showed significant improvement in VT severity and some rats showed normal performance. VT(VP) incidence in control, model and propranolo were 0(0), 100%(100%), 40%(50%), respectively.
Comparison of cTnI in the rats in each group
Compared with control group, the cTnI level in the model group was significantly increased(P<0.01). Compared with model group, the cTnI level in the propranolol group was significantly decreased (P<0.01). (Fig 2).
Fig2 Comparison of serum cTnI level in rats serum Data are presented as mean ± standard error of mean. ***P<0.01,statistical comparison between control group and model group; ###P<0.01, statistical comparison between propranolol group and model group.
Comparison of oxidative stress levels in the rats in each group
Compared with control group, the SOD and GSH level in the model group were significantly decreased (P<0.01). Compared with model group, the level in the propranolol group were significantly increased (P<0.01)(Fig 3a, 3b). Compared with control group, the MDA and NO level in the model group were significantly increased(P<0.01). Compared with model group, the level in the propranolol group were significantly decreased (P<0.05 or P<0.01)(Fig 3c, 3d).
Fig 3 Comparison of oxidative stress level in rats serum Fig3a shows that the SOD level of each group was compared Fig3b shows that the GSH level of each group was compared Fig3c shows that the MDA level of each group was compared Fig3d shows that the NO level of each group was compared Data are presented as mean ± standard error of mean. ***P<0.01,statistical comparison between control group and model group;#P<0.05 and ###P<0.01, statistical comparison between propranolol group and model group.
Comparison of inflammatory factors in the rats in each group
Compared with control group, the IL-6, IL-1β and TNF-α level in the model group were significantly increased (P<0.01). Compared with model group, the level in the propranolol group were significantly decreased(P<0.05 or P<0.01) (Fig 4).
Fig4 Comparison of inflammatory factors level in rats serum Fig4a shows that the IL-6 level of each group was compared; Fig4b shows that the IL-1β level of each group was compared; Fig4c shows that the TNF-α level of each group was compared. Data are presented as mean ± standard error of mean. ***P<0.01,statistical comparison between control group and model group;#P<0.05 and ###P<0.01, statistical comparison between propranolol group and model group.
Comparison of pathological changes of myocardial tissue in each group
HE staining showed that no obvious abnormality was found in myocardial tissue of control group. Compared with the control group, the myocardial tissue of rats in the model group showed obvious changes, such as edema, inflammatory cell infiltration, myocardial cell necrosis and dissolution. The myocardial tissue of rats in the propranolol group was obviously improved(Figure 5).
Fig 5 Comparison of pathological changes of myocardial tissue in each group a: control group, b: model group, c: propranolol group.
Comparison of CaMKII activity in the rats in each group
Compared with control group, the CaMKII activity in the model group was significantly increased (P<0.01). Compared with model group, the activity in the propranolol group was significantly decreased (P<0.05) (Fig 6).
Fig 6 Comparison of CaMKII activity in rat cardiomyocytes Data are presented as mean ± standard error of mean. ***P<0.01,statistical comparison between control group and model group;#P<0.05, statistical comparison between propranolol group and model group.
Western blot analysis of CaMKII and OX-CaMKII protein expression in cardiomyocytes
Compared with control group, the CaMKII and OX-CaMKII expression in the model group were significantly increased (P<0.01). Compared with that in the model group, the expression in the propranolol group was significantly decreased (P<0.01). (Fig 7).
Fig 7 Expression of CaMKII and OX-CaMKII in rat cardiomyocytes by Western blot Fig7a shows that the CaMKII expression of each group was compared; Fig7b shows that the OX-CaMKII expression of each group was compared. Data are presented as mean ± standard error of mean.***P<0.01,statistical comparison between control group and model group; ###P<0.01,statistical comparison between propranolol group and model group.
Western blot analysis of SERCA2 and P-PLB protein expression in cardiomyocytes
Compared with control group, the SERCA2 protein expression level in the model group was significantly decreased (P<0.01). Compared with model group, the expression in the propranolol group was significantly increased (P<0.01) (Fig8a).Compared with control group, the P-PLB protein expression level in the model group was significantly increased (P<0.01). Compared with model group, the expression in the propranolol group was significantly decreased (P<0.01) (Fig 8b).
Fig 8 Expression of SERCA2 and P-PLB in rat cardiomyocytes by Western blot Fig8a shows that the SERCA2 expression of each group was compared; Fig8b shows that the P-PLB expression of each group was compared. Data are presented as mean ± standard error of mean.***P<0.01,statistical comparison between control group and model group; ###P<0.01,statistical comparison between propranolol group and model group.
Comparison of CaMKII δ mRNA and SERCA2 mRNA expression in the rats in each group
Compared with control group, the CaMKIIδ mRNA expression level in the model group was significantly increased (P<0.01). Compared with model group, the expression in the propranolol group was significantly decreased (P<0.01) (Fig 9a).Compared with control group, the SERCA2 mRNA expression level in the model group was significantly decreased (P<0.01). Compared with model group, the expression in the propranolol group was significantly increased (P<0.01) (Fig 9b).
Fig 9 The expression of CaMKIIδmRNA and SERCA2 mRNA in rat myocardial tissue with Real-time PCR Fig9a shows that the CaMKIIδmRNA expression of each group was compared; Fig9b shows that the SERCA2 mRNA expression of each group was compared. Data are presented as mean ± standard error of mean.***P<0.01,statistical comparison between control group and model group; ###P<0.01,statistical comparison between propranolol group and model group.
Comparison of Ca2+ levels in rat myocardial tissue in each group
Compared with control group, the Ca2+ level in myocardial tissue in the model group was significantly increased (P<0.01). Compared with model group, the level in myocardial tissue in the propranolol group was significantly decreased (P<0.01) (Fig 10).
Fig 10 Comparison of Ca2+ level in rat myocardial tissue Data are presented as mean ± standard error of mean. ***P<0.01,statistical comparison between control group and model group; ###P<0.01, statistical comparison between propranolol group and model group.