多环芳烃(PAHs)对鱼类具有胚胎和心脏毒性,可能与细胞内Ca2管理不当有关。由于Sarco(endo)质网Ca2-ATPase(SERCA)是细胞内Ca2的主要调节因子,在存在3和4循环PAHs的情况下,测量了虹鳟鱼(Oncorhynchusmykiss)心室的SERCA活性和收缩特性。在普通心室匀浆中,SERCA急性暴露于0.1-1.0μM菲(Phe),retene(Ret),荧蒽(流感),或芘(Pyr)导致SERCA活性的浓度依赖性增加,除了流感暴露,在1μM时具有49.7-83%的最大效果。然而,PAH混合物不影响鳟鱼心室带的收缩参数。同样,所有PAHs,除了Ret,增加了肌体SERCA活性,但效果较低(1μM时为27.8-40.8%)。为了研究PAHs对SERCA的慢性影响,编码鳟鱼心脏SERCA的atp2a2a基因在人胚肾(HEK)细胞中表达。在0.3-1.0μMPhe存在下培养HEK细胞,Ret,流感,和Pyr4天以浓度依赖的方式抑制SERCA表达,最大抑制49%,65%,39%(P<0.05),和18%(P>0.05),分别为1μM。目前的发现表明,亚微摩尔PAH浓度对SERCA的影响不同:在急性暴露中刺激SERCA活性,在慢性暴露中抑制SERCA表达。SERCA的抑制表达可能通过抑制肌肉功能和改变基因表达来促进PAHs的胚胎和心脏毒性。
Polycyclic aromatic hydrocarbons (PAHs) are embryo- and cardiotoxic to fish that might be associated with improper intracellular Ca2+ management. Since sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) is a major regulator of intracellular Ca2+, the SERCA activity and the contractile properties of rainbow trout (Oncorhynchus mykiss) ventricle were measured in the presence of 3- and 4-cyclic PAHs. In unfractionated ventricular homogenates, acute exposure of SERCA to 0.1-1.0 μM phenanthrene (Phe), retene (Ret), fluoranthene (Flu), or pyrene (Pyr) resulted in concentration-dependent increase in SERCA activity, except for the Flu exposure, with maximal effects of 49.7-83 % at 1 μM. However, PAH mixture did not affect the contractile parameters of trout ventricular strips. Similarly, all PAHs, except Ret, increased the myotomal SERCA activity, but with lower effect (27.8-40.8 % at 1 μM). To investigate the putative chronic effects of PAHs on SERCA, the atp2a2a gene encoding trout cardiac SERCA was expressed in human embryonic kidney (HEK) cells. Culture of HEK cells in the presence of 0.3-1.0 μM Phe, Ret, Flu, and Pyr for 4 days suppressed SERCA expression in a concentration-dependent manner, with maximal inhibition of 49 %, 65 %, 39 % (P < 0.05), and 18 % (P > 0.05), respectively at 1 μM. Current findings indicate divergent effects of submicromolar PAH concentrations on SERCA: stimulation of SERCA activity in acute exposure and inhibition of SERCA expression in chronic exposure. The depressed expression of SERCA is likely to contribute to the embryo- and cardiotoxicity of PAHs by depressing muscle function and altering gene expression.