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Study on the Function of Muscarinic Cholinergic Receptor Subtypes of Internal Mammary Artery in Vitro

Objective To study the method to inhibit perioperative internal mammary artery (IMA) spasm from the perspective of muscarinic receptor, and research the function of muscarinic cholinergic receptor subtypes of IMA. Methods IMA segments in vitro with intact endothelium were obtained from 30 patients who underwent coronary artery bypass grafting (CABG). According to muscarinic receptor antagonists of different concentrations， They were divided into control group (not using receptor antagonist), atropine group (nonselective M receptor antagonist), pirenzepine group (M1 receptor antagonist) and Methoctramine group(M2 receptor antagonist) by random number table. The effects of antagonists on vasodilatation were analyzed, Scott ratio was used to calculate affinity index (pD2) and Schild plot was used to count rivalry index (pA2). Results Acetylcholine (Ach)induced concentrationdependentrelaxation response of IMA segments with intact endothelium precontracted with potassium chloride (KCl). The pD2 was 6.92±0.05. The effects of atropine, pirenzepine and methoctramine on doseresponse curve induced by Ach with intact endothelium were all concentrationdependent. With the increase of the concentration of antagonists, the Achinduced doseresponse curves had a significant shift to right(Plt;0.05). Atropine, pirenzepine and Methoctramine competitively antagonized the reaction of vessel to Ach. The pA2 were 9.62±0.15,7.70±0.08 and 630±0.08, respectively. Conclusion The Achinduced relaxation response of IMA with intact endothelium is concentrationdependent. According to the affinity of different antagonist, IMA in Vitro Achinduced relaxation response is implemented by acting on nonneuronal muscarinic cholinergic M1 receptor subtype.

室间隔缺损合并右室流出道室性早搏二例

A model of transplanting neonatal cardiomycytes into the wall of rat inferior vena cava

Objective To establish a model of transplanting neonatal cardiomycytes into the wall of rat inferior vena cava. Methods Neonatal cardiomyocytes (n=6, 5×106cells each, A group) or medium (n=6, B group) only were transplanted into the wall of inferior vena cava in female Fisher rats. At 21 days after transplantation, the contraction of transplanted cardiomyocytes was assessed and the inferior vena cava was processed for histology. Results Distinct rhythmic beating of the vena cava at the site of cell transplantation before and after the aorties were clamped (at a rate 141± 47 rpm and 88± 44 rpm which was dramaticly lower than aortic beating, with a statistical difference at P value of 0.03). Cardiomyocyte was seen in 6 rats who had neonatal cardiomyocyte transplantation, but not in 6 rats receiving media. Hematoxylin and eosin staining showed viable cardiomyocytes in the wall of the vena cava in 6 rats treated with neonatal cardiomyocytes, but not in 6 rats receiving media. Conclusion This study shows that neonatal cardiomyocytes can survive, mature and spontaneously and rhythmically contract after they are transplanted in the wall of inferior vena cava.

Effect of ozone on oxidative stress and energy metabolism change of blood from aortic dissection patients in vitro

ObjectiveTo investigate the effect of ozone on oxidative stress and energy metabolism change of blood from aortic dissection (AD) patients for providing preliminary evidence of application of ozonated autohemotherapy (ozone-AHT) in AD patients. MethodsTwenty AD patients (16 males and 4 females with a mean age of 48.51±10.21 years) were consecutively included in the First Affiliated Hospital of Harbin Medical University from March 2016 to August 2016, and blood samples were collected from all participants and ozonized in vitro at different ozone concentrations (0 μg/ml, 40 μg/ml, 60 μg/ml, 80 μg/ml, 160 μg/ml). Malondialdehyde (MDA), red blood cells (RBCs) superoxide dismutase (SOD), Na+-K+-ATP, 2,3-bisphosphoglyceric acid (2,3-DPG) at different ozone concentrations were evaluated by enzyme-linked immunosorbent assay (ELISA). ResultsIn the control group (0 μg/ml), the content of postoperative MDA was significantly higher than that of preoperation (P<0.05). The contents of postoperative SOD, Na+-K+-ATP and 2,3-DPG were significantly lower than that of preoperation (P<0.05). The content of MDA at the concentrations of 40 μg/ml, 60 μg/ml, 80 μg/ml group increased after the operation (P>0.05), and the SOD, Na+-K+-ATP, 2,3-DPG decreased compared with the preoperation (P>0.05). But all the values were not statistically significant at the concentrations of 40 μg/ml, 80 μg/ml and 160 μg/ml respectively between preoperation and postoperation (P>0.05). Compared with other concentration groups, the content of preoperative and postoperative MDA increased in the ozone group (160 μg/ml), and oppositely, the contents ofpreoperative and postoperative SOD, Na+-K+- ATP and 2,3-DPG decreased (P<0.05). Conclusion The concentrations of 40 to 80 μg/ml of ozone can improve the antioxidant capacity of erythrocyte membrane, reduce oxidative stress in blood samples of AD patients and improve the energy metabolism of erythrocyte membranes, so the concentration range of ozone is safe and feasible for the ozone-AHT of perioperative AD.

TLR4/NF-κB signaling pathway regulates inflammatory response involved in pathophysiological mechanisms of type A aortic dissection

Objective To investigate activated toll-like receptor-4 (TLR4) signaling pathway involved in pathophysiological mechanisms of type A aortic dissection (TAAD). Methods Specimens of full-thickness ascending aorta wall from the TAAD patients (n=12) and the controlled donors (n=12) were collected. Western blotting was used to examine the associated proteins' expression of TLR4 signaling pathway. Blood samples from TAAD (n=43) and controlled patients (n=50) were examined by enzyme-linked immunosorbent assay (ELISA) to detect the circulating plasma cytokines levels of interleukin-1β (L-1β). Results In the aortic wall of TAAD, expression levels of TLR4 and protein expression of major molecule significantly elevated, and activated macrophages increased. Furthermore, elevated IL-1β levels were observed in the TAAD patients’ plasma compared with the control plasma. Multiple logistic regression analysis and receiver operating characteristic (ROC) curve showed that elevated IL-1β could be a novel and promising biomarker with important diagnostic and predictive value in the identification of TAAD. Conclusion Activated TLR4/NF-κB signaling pathway regulates inflammatory response to involve in pathophysiological mechanisms of type A aortic dissection and its regulated inflammatory products have important predictive value for patients with TAAD.