Abstract: Objective To explore the effect of sulfur dioxide(SO₂) on the endoplasmic reticulum stress(ERS) in the aortic smooth muscle cells of spontaneously hypertensive rat(SHR). Methods Seven male WKY rats were used as WKY control group. Twelve male SHRs at the age of 4 weeks were randomly divided into SHR control group and SHR+SO₂ donor(Na₂SO₃/NaHSO₃) group, respectively. Five weeks later, the blood pressure was determined. SO₂ content in the plasma was detected by reversephase high performance liquid chromatography with fluorescence detection(HPLC). The expressions of glucose-regulated protein 78(GRP78) and caspase-12 in the aortic smooth muscle cells were measured by immuohistochemistry. Results Compared with WKY control group, SO₂ contents in the plasma were decreased, while the blood pressure and the expressions of GRP78 and caspase-12 in the aortic smooth muscle cells were increased in the rats of SHR control group significantly, respectively. Administration of SO₂ donor increased the SO₂ content in the plasma in the rats of SHR control group. Moreover, SO₂ donor decreased the blood pressure and the expressions of GRP78 and caspase-12 in the aortic smooth muscle cells of SHR control rats. Conclusion SO₂ might inhibit the activation of ERS in the aortic smooth muscle cells of hypertensive rats.

Key words: sulfur dioxide, hypertension, aortic, endoplasmic reticulum stress