| Objectives The study was designed to observe the histopathological changes of myocardium and aorta,and levels of oxidative stress and inflammatory factors in serum and myocardium in rats co-exposed to atmospheric particulate matter and high fat and high sugar diet.The purpose of this study was to explore the effect of combined exposure to airborne particulates and high-fat and high-sugar diets on myocardium damage.Methods Forty-eight male Sprague-Dawley rats aged 3 weeks were randomly divided into four groups(n=12 in each group): control group(ordinary diet,no PM exposure,CC group for short),high fat and high sugar group(high fat and high sugar diet feed,no PM exposure,HC group for short),atmospheric particulates group(ordinary diet,exposure to PM,CP group for short),and high fat and high sugar diet plus airborne particulate exposure group(high fat and high sugar diet,exposure to PM,HP group for short).Rats in CC and HC group were placed in separate venting cages containing high-efficiency filter to filter outdoor atmospheric particules,rats in CP and HP groups were placed into separate venting cages without high-efficiency filter and exposed to the air outdoor.After 3 months and 6 months of exposure,the heart rate and blood pressure of rats were measured using a noninvasive blood pressure monitor.The levels of IL-6,CRP,MCP-1,VCAM-1 and HO-1 in serum were detected by ELISA.The SOD activity and MDA content in myocardium and serum were detected by the kit.The protein expressions of IL-6,CRP,MCP-1,VCAM-1 and HO-1 in myocardium of rats were detected by immunohistochemistry and western blotting.HE staining was used to observe the pathological changes of myocardial tissue and artery.Results Atmospheric particulate matter exposured for 3 months: 1 The SBP and DBP in HC,CP,and HP group were higher than those in CC group.The DBP and HR in HC,HP group were higher than those in CC group(P<0.05).2 Compared with CC and CP group,the MDA content and SOD activity in serum of HP group both increased(P<0.05).3 Compared with CC and CP group,the MDA content and SOD activity in serum of HP group were all increased(P<0.05).4 Compared with the other three groups,the expression of IL-6,CRP,MCP-1,and VCAM-1 protein in the myocardium of rats in HP group increased,and the expression of HO-1 decreased,which was basically consistent with the results of immunohistochemistry.5 There was no significant inflammatory infiltration in CC group,inflammatory infiltrates were observed in the myocardium of HC group.The myocardium in CP group was slightly cluttered with focal inflammation.The myocardial cells in HP group arranged in disorder,inflammatory cell infiltration and partial edema of cardiomyocytes.6 In CC group and HC group,the arterial smooth muscle cells were arranged neatly and no elastic fibers were broken;arterial subendothelial space widening in CP group;In HP group,the arterial media thickens and the subendothelial space widens,showing some elastic fiber breakage.Atmospheric particulate matter exposured for 6 months: 1 The SBP and DBP in HP and HC groups were higher than those in CC group.The DBP was higher in HP group than HC and CP groups(P<0.05).2 The levels of IL-6,CRP,MCP-1,VCAM-1,and MDA in serum in HP and HCgroupswere higher than those in CC group.The content of HO-1 in serum was lower than that in CC group.The levels of IL-6,VCAM-1,OX-LDL,and MDA in serum of HP group were higher than those in CP group.The activities of HO-1 and SOD in serum were lower than those in CP group(P<0.05).3 Compared with CC group,the MDA content in CP group and HP group was increased,and the SOD activity was decreased;the MDA content in HP group was higher than that in HC and CP group(P < 0.05).4 Compared with the other three groups,the expression of IL-6,CRP,MCP-1 and VCAM-1 protein in the myocardium of rats in HP group increased,and the expression of HO-1 was decreased(P< 0.05),basically consistent with the results of immunohistochemistry.5 The myocardial structure of CC group was intact,neatly arranged,and slightly inflammatory infiltrated;the myocardium in HC group was relatively intact,the inflammatory cell infiltrate appeared in the gap,and the vacuolarlike changes of the cells were observed;the myocardium in CP group had mild inflammatory infiltration;In HP group,myocardial cells were arranged disorderly,inflammatory infiltrates increased,and myocardial cells edema and degeneration.6 In CC group,the arterial smooth muscle cells were arranged neatly and no elastic fibers were broken.In HC group,arterial media thickening,elastic fibers arranged disorderly,and inflammatory infiltration.The structure of CP group was complete,and elastic fibers were arranged neatly.In HP group,the arterial media thickened,the elastic fibers became disorganized and fractured,and the endothelial cells were arranged in disorder and apoptosis.Conclusions 1 Both high fat and high sugar diets and airborne particulates can increase diastolic blood pressure,and inflammatory and oxidative damage in serum and myocardium.Myocardial tissue formed infiltration of inflammation.2 Co-exposure to high fat and high sugar diets and atmospheric particulates can increase inflammatory and oxidative damage in myocardial tissue of rats.Myocardial tissue showed edema and inflammatory infiltration.The arterial media thickened and the elastic fibers broke. |
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