Studies on the action of bacterial thiol-activated hemolysins on endothelial cells of pulmonary circulation.

采用大鼠整体、离体主动脉环和培养的内皮细胞研究了细菌巯基活化溶血素、肉毒梭菌的肉毒杆菌溶血素（BL）和产气荚膜梭菌的θ毒素对动物肺循环的影响.用1，000 HU BL中毒的大鼠表现出左心衰伴进行性心动过缓和低血压，死亡时间为15.6（±）SY。[)2毒素注射后0 min。另一方面，用10，000 HU θ毒素中毒的大鼠表现出右心衰竭，伴有呼吸急促、肺水肿、右心房和心室腔中的凝块形成以及肝充血，并在21.8（±）SY. [)2.8注射后1 min。离体大鼠心脏灌流BL后，冠脉循环阻力明显增加，而theta毒素灌流后，冠脉循环阻力增加不明显.乙酰胆碱诱导的离体大鼠主动脉环的内皮依赖性舒张被两种溶血素抑制。1 HU/ml的BL和1 HU/ml的θ毒素对乙酰胆碱浓度-反应曲线的影响程度基本相同.猪和豚鼠主动脉内皮细胞对两种溶血素的敏感性高于其他哺乳动物细胞。50%有效浓度的BL和Theta毒素对培养的猪和豚鼠内皮细胞的细胞毒作用无显著性差异，表明这两种溶血素在体内均对内皮细胞有作用。Theta毒素优先作用于肺循环系统，而BL优先作用于冠状动脉循环系统，尽管两种溶血素在体外和现场对主动脉内皮细胞的作用相似。结果表明，θ毒素作为一个可能的致病剂成人呼吸窘迫综合征的气性坏疽。

Effects of bacterial thiol-activated hemolysins, botulinolysin (BL) of Clostridium botulinum and theta toxin of C.perfringens, on the pulmonary circulation of the animals were studied using whole rats, isolated aortic rings, and cultured endothelial cells.1. Rats intoxicated with 1,000 HU of BL showed left heart failure with progressive bradycardia and hypotension, and died 15.6(]SY.+-。[)2,0 min after the toxin injection. On the other hand, rats intoxicated with 10,000 HU of theta toxin showed right heart failure with tachynea, lung edema, clot formation in right atrial and ventricular cavities, and liver congestion, and died 21.8(]SY.+-。[)2.8 min after the injection.2. In vitro perfusion of BL into isolated rat hearts caused marked increase in resistance of coronary circulation while perfusion of theta toxin did just a little.3. Acetylcholine-induced endothelium-dependent relaxation of isolated rat aortic rings was inhibited by both hemolysins. The extent of rightward shifts of concentration-response curve of acetylcholine by 1 HU/ml of BL and 1 HU/ml of theta toxin were almost the same.4. Swine and gunea pig aortic endothelial cells were very much sensitive to both hemolysins comparing with other nuclearated mammalian cells in culture. No significant difference was obserrved between 50% effective concentrations of BL and that of theta toxin in their cytotoxic action against swine and guinea pig endothelial cells culture.The results obtained in this study show taht both hemolysins act on endothelial cells in vivo. Theta toxin preferentially acts on the pulmonary circulation system while BL acts preferentially on the coronary circulation system, though both hemolysins act similarly on aortic endothelial cells in vitro and in site. The results suggest theta toxin as a possible causative agent for adult respiratory distress syndrome in gas gangrenes.