Respirable Particulate Matter On Rat Heart Sympathetic Distributed And Nerve Growth Factor Expression And Beta Blockers Intervention Role

Objective1. To observe the pathological damage of PM2.5on the heart and lung tissue.2. To assess the effect of PM2.5on sympathetic innervation, identify the ability on the sympathetic nerve reconstruction of PM2.5.3. To study the effects of β-receptor blocker on sympathetic nerve reconstruction, identify the β-receptor blocker on preventing infaust influences of PM2.5.MethodsSixty healthy SD rats were randomized into3groups:control group,experimental group and propranolol group. Each rat was anesthetized and instilled into trachea with two different solutions twice per week for four weeks:experimental group and propranolol group with PM2.525mg(1ml)/kg and control group with saline1ml/kg; In propranolol group, propranolol50mg/kg-d was given especially. All rats were killed4weeks later and biatrial appendages, two ventricular anterior walls were left. Immune cytochemical staining of cardiac sympathetic nerves was performed using anti-tyrosine hydroxylase antibodies. Additional, we observed the pathological change of the inferior lobe of right lung and the left ventricle by HE staining.Results1. There was slight histopathological change of heart tissue and obviously pathological damage of lung tissue in the experimental ang propranol group.2. There was no significant difference of the density of TH-positive sympathetic nerves in the atria among three groups (P>0.05)3. Compared with the control group, the density of sympathetic nerves of experimental group were much higher in the left and right ventricular anterior wall (P<0.05).4. The density of sympathetic nerves in the left ventricular anterior wall of propranolol group were much lower than that of experimental group(P<0.05), but still higher than control group(P<0.05); The density of sympathetic nerves in the right ventricular anterior wall of propranolol group were also much lower than that of experimental group, and had no significant difference compared with control group(P>0.05)Conclusion1. Particulate matter PM2.5can induce more serious pathological damage in lung tissue than heart tissue.2. Particulate matter PM2.5can induce regional sympathetic hyperinnervation in left and right ventricular anterior walls in healthy rats, which confirmed the ability of PM2.5on the sympathetic nerve reconstruction.3. β blocker play a important role in preventing infaust influences of particulate matter PM2.5. Objective1. To observe the effect of Particulate matter PM2.5on cardiac nerve growth factor with RT-PCT and Western blotting.2. To research the relationship of the density of sympathetic innervation with the expression of cardiac nerve growth factor, explore the possible arrhythogenic mechanism of PM2.5.3. To observe the effects of β-receptor blocker on the expression of NGF, explore the way of β-receptor blocker on preventing sympathetic nerve reconstruction of PM2.5.MethodsSixty healthy SD rats were randomized into3groups:control group,experimental group and propranolol group. Each rat was anesthetized and instilled into trachea with two different solutions twice per week for four weeks:experimental group and propranolol group with PM2.525mg(1ml)/kg and control group with saline1ml/kg; In propranolol group, propranolol50mg/kg-d was given especially. All rats were killed4weeks later and biatrial appendages, two ventricular anterior walls were left. Cardiac nerve growth factor was detected by western blotting and quantitative real-time PCR.Results1. There was no significant difference of expression of NGF in the atria among three groups (P>0.05)2. Compared with the control group, the expression of cardiac NGF of experimental group were much higher in the left and right ventricular anterior wall (P<0.05), the density of sympathetic nerves and the expression of cardiac NGF correlated positive significant(P<0.05).3. The expression of cardiac NGF in the left ventricular anterior wall of propranolol group were much lower than that of experimental group(P<0.05), but still higher than control group(P<0.05); The expression of cardiac NGF in the right ventricular anterior wall of propranolol group were also much lower than that of experimental group, and had no significant difference compared with control group (P>0.05)Conclusion1. PM2.5can lead to the higher expression of cardiac NGF in both sides of ventricular anterior walls, which correlated well with the higher density of sympathetic nerves, that maybe was the important arrhythogenic mechanism of PM2.5.2. β-receptor blocker can prevent sympathetic nerve reconstruction by restrain the expression of NGF, confirmed the way of β-receptor blocker on preventing sympathetic nerve reconstruction of PM2.5.