Effect of sulfur dioxide on endoplasmic reticulum stress protein expression in myocardial tissue of rats with left to right shunt

Abstract

Objective To explore the possible role of sulfur dioxide(SO2) in endoplasmic reticulum stress(ERS) protein expression in myocardial tissue of rats with left to right shunt. Methods A total of 24 male Sprague Dawley rats were randomly divided into sham group(n=8), shunt group(n= 8)and shunt plus SO2 donor group(n= 8). The rats of shunt group and shunt plus SO2 donor group, an abdominal aorta and inferior vena cava shunting was created.Na2SO3/NaHSO3 was administrated intra-peritoneally in rats of shunt plus SO2 donor group.Eight weeks later, the ratio of quantity of pulmonary to quantity of system(Qp/Qs) was measured; Heart weight/body weight(HW/BW) and right ventricle/left ventricle+ ventricular septum [RV/(LV+ SP)] were detected; Expressions of collagen type Ⅰ in right ventricle myocardial tissue was measured by enzyme linked immunosorbent assay(ELISA); High performance liquid chromatography was used to measure SO2 content in right ventricle myocardial tissue.Glucose regulated protein 78(GRP78), c-jun N-terminal kinase(JNK) and phosphorylation-c-jun N-termina kinase(p-JNK) mRNA and protein expressions in RV myocardial tissue were detected by Western blot and real time-polymerase chain reaction(RT-PCR). Results After 8-weeks shunting, Qp/Qs in the shunt and shunt plus SO2 groups were higher significantly than those of the sham group(all P<0.05). Compared with sham group, HW/BW, RV/LV+ SP and expressions of collagen type Ⅰ in the shunt group were significantly higher(all P<0.05). Treatment of SO2, HW/BW and RV/LV+ SP and collagen type Ⅰ in the shunt group were lower significantly(all P<0.05). The level of SO2 of RV in shunt group increased significantly compared with sham group(all P<0.05), but significantly lower than that of shunt plus SO2 donor group(P<0.05). Compared with sham group, the expressions of GRP78, JNK and p-JNK mRNA and protein in RV increased significantly in shunt group(P<0.05). After treatment with SO2, the expressions of GRP78, JNK and p-JNK mRNA and protein decreased significantly(P<0.05). Conclusion SO2 might protect RV myocardial tissue of the rats with left-right shunt by regulating the expressions of ERS. Key words: Sulfur dioxide; Endoplasmic reticulum stress; Glucose regulated protein 78; c-jun N-terminal kinase; Phosphorylation-c-jun N-terminal kinase