Particulate Matter 2.5 Induced Developmental Cardiotoxicity in Chicken Embryo and Hatchling

Particulate matter poses health risk to developing organisms. To investigate particulate matters with a diameter smaller than 2.5 um (PM2.5)-induced developmental cardiotoxicity, fertile chicken eggs were exposed to PM2.5viaair cell injection at doses of 0.05, 0.2, 0.5, 2, and 5 mg/egg kg. Morphological changes in the embryonic day four (ED4) and hatchling hearts were assessed with histological techniques. Heart rates of hatchling chickens were measured with electrocardiography. The protein expression levels of nuclear factor kappa-light-chain-enhancer of activated B cells p65 (NF-kb p65), inducible nitric oxide synthase (iNOS), and matrix metallopeptidase 9 (MMP9) were assessed with immunohistochemistry or western blotting in hatchling hearts. PM2.5 exposure elevated areas of heart in ED4 embryo, increased heart rate, and thickened right ventricular wall thickness in hatchling chickens. Immunohistochemistry revealed enhanced NF-kb p65 expression in hatchling hearts. Western blotting results indicated that both iNOS and MMP9 expression were enhanced by lower doses of PM2.5 exposure (0.2 and 0.5 mg/kg) but not 2 mg/kg. In summary, developmental exposure to PM2.5 induced developmental cardiotoxicity in chicken embryo and hatchling chickens, which is associated with NF-kb p65, iNOS, and MMP9.

颗粒物对发育中的生物体构成健康风险。为了研究直径小于2.5微米的颗粒物（PM2.5）诱导的发育性心脏毒性，将可孵化的鸡蛋通过气室注射分别暴露于0.05、0.2、0.5、2和5毫克/每千克鸡蛋的PM2.5剂量下。采用组织学技术评估胚胎第4天（ED4）和雏鸡心脏的形态变化。用心电图测量雏鸡的心率。采用免疫组织化学或蛋白质印迹法评估雏鸡心脏中核因子κB轻链增强子活化的B细胞p65（NF - κB p65）、诱导型一氧化氮合酶（iNOS）和基质金属蛋白酶9（MMP9）的蛋白表达水平。PM2.5暴露增加了ED4胚胎的心脏面积，提高了雏鸡的心率，并使雏鸡右心室壁厚度增加。免疫组织化学显示雏鸡心脏中NF - κB p65表达增强。蛋白质印迹结果表明，较低剂量的PM2.5暴露（0.2和0.5毫克/千克）可增强iNOS和MMP9的表达，但2毫克/千克剂量则无此作用。总之，发育过程中暴露于PM2.5会诱导鸡胚胎和雏鸡的发育性心脏毒性，这与NF - κB p65、iNOS和MMP9有关。