Department of Emergency Medicine, Beijing Jishuitan Hospital, Beijing 100035, China.
Chin Med J (Engl). 2011 Nov;124(21):3460-7.
Atherosclerosis is an important cardiovascular disease, becoming a major and increasing health problem in developed countries. However, the possible underlying mechanisms were not completely clear. In 2009, our research group first discovered that hydrogen sulfide (H(2)S) as a novel gastrotransmitter played an important anti-atherosclerotic role. The study was designed to examine the regulatory effect of hydrogen sulfide (H(2)S) on endoplasmic reticulum stress (ERS) in apolipoprotein E knockout (apoE(-/-)) mice fed a Western type diet.
C57BL/6 mice and homozygous apoE(-/-) mice were fed a Western type diet. C57BL/6 mice were injected intraperitoneally with normal saline (5 ml/kg per day) as control group. The apoE(-/-) mice were treated with the same dose of normal saline as the apoE(-/-) group, injected intraperitoneally with sodium hydrosulfide (NaHS, an H(2)S donor, 56 µmol/kg per day) as the apoE(-/-) + NaHS group and injected intraperitoneally with DL-propargylglycine (PPG, a cystathionine-γ-lyase inhibitor, 50 mg/kg, per day) as the apoE(-/-) + PPG group. After 10 weeks, the mice were sacrificed and the plasma lipids were detected. Sections of aortic root from these animals were examined for atherosclerotic lesions by HE and oil red O staining. The aortic ultrastructure and microstructure were analyzed with the help of light and electronic microscope. Glucose-regulated protein 78 (GRP78), caspase-12, copper-andzinc-containing superoxide dismutase (Cu/ZnSOD) and Mn-containing superoxide dismutase (MnSOD) protein expression in aortic tissues were detected with immunohistochemistry. The level of intracellular reactive oxygen species (ROS) were measured by using a commercial assay kit.
Compared with control mice, apoE(-/-) mice showed increased plasma levels of total cholesterol (TC), triglyceride (TG) and low density lipoprotein (LDL), decreased high density lipoprotein (HDL), increased aortic plaque size, destroyed ultra-structure of aortic tissue, and increased expression of GRP78 and caspase-12 proteins. Compared with apoE(-/-) mice, H(2)S donor-treated apoE(-/-) mice showed a decreased plasma LDL level, lessened plaque necrosis and attenuated aortic ultra-structural disorder. H(2)S donor-treatment induced GRP78 expression but suppressed caspase-12 expression in aortic lesions. However, compared with apoE(-/-) mice, PPG treated apoE(-/-) mice showed enlarged plaque size, more severe ultrastructural disorder of the aortic tissue and reduced GRP78 staining in aortic lesions. The plasma lipids and the staining of caspase-12 in apoE(-/-) + PPG rats did not significantly differ from those in the apoE-/-mice. Consistently, H(2)S induced SOD expression, accompanied by a reduced level of ROS.
H(2)S plays a regulatory role in aortic ERS and reduces atherosclerotic lesions in apoE(-/-) mice fed with a Western type diet.
动脉粥样硬化是一种重要的心血管疾病，在发达国家已成为一个主要且日益严重的健康问题。然而，其潜在的机制尚不完全清楚。2009 年，我们的研究小组首次发现，作为一种新型胃肠递质的硫化氢（H2S）在抗动脉粥样硬化方面发挥着重要作用。本研究旨在探讨硫化氢（H2S）对载脂蛋白 E 敲除（apoE（-/-））小鼠给予西方饮食后内质网应激（ERS）的调节作用。
将 C57BL/6 小鼠和纯合子 apoE（-/-）小鼠喂以西方饮食。C57BL/6 小鼠腹腔内注射生理盐水（5ml/kg/天）作为对照组。apoE（-/-）小鼠给予相同剂量的生理盐水作为 apoE（-/-）组，腹腔内注射硫氢化钠（NaHS，H2S 供体，56μmol/kg/天）作为 apoE（-/-）+NaHS 组，腹腔内注射 DL-丙炔甘氨酸（PPG，胱硫醚-γ-裂解酶抑制剂，50mg/kg/天）作为 apoE（-/-）+PPG 组。10 周后处死小鼠，检测血浆脂质。用 HE 和油红 O 染色法观察主动脉根部粥样硬化病变。在光镜和电子显微镜下分析主动脉超微结构和微观结构。用免疫组化法检测主动脉组织葡萄糖调节蛋白 78（GRP78）、半胱天冬酶-12、铜锌超氧化物歧化酶（Cu/ZnSOD）和锰超氧化物歧化酶（MnSOD）蛋白的表达。用商业试剂盒测定细胞内活性氧（ROS）的水平。
与对照组小鼠相比，apoE（-/-）小鼠的血浆总胆固醇（TC）、甘油三酯（TG）和低密度脂蛋白（LDL）水平升高，高密度脂蛋白（HDL）水平降低，主动脉斑块增大，主动脉组织超微结构破坏，GRP78 和半胱天冬酶-12 蛋白表达增加。与 apoE（-/-）小鼠相比，H2S 供体处理的 apoE（-/-）小鼠的血浆 LDL 水平降低，斑块坏死减轻，主动脉超微结构紊乱减轻。H2S 供体处理诱导了 GRP78 的表达，但抑制了主动脉病变中半胱天冬酶-12 的表达。然而，与 apoE（-/-）小鼠相比，PPG 处理的 apoE（-/-）小鼠的斑块增大，主动脉组织超微结构紊乱更严重，GRP78 染色减少。apoE（-/-）+PPG 大鼠的血浆脂质和半胱天冬酶-12 染色与 apoE（-/-）小鼠无显著差异。同样，H2S 诱导 SOD 表达，同时降低 ROS 水平。
H2S 在内质网应激中起调节作用，可减少西方饮食喂养的 apoE（-/-）小鼠的动脉粥样硬化病变。
