Thomé G R, Mazzanti C M, Ahmed M, Corrêa M, Spanevello R M, Maldonado P A, Luchese C, Cargnelutti D, Morsch V M, Duarte M M M F, Fiorenza A M, Nogueira C W, De Bona K S, Moretto M B, Da Luz S C A, Mazzanti A, Schetinger M R C
Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, RS, Brazil.
Inhal Toxicol. 2009 Sep;21(11):906-12. doi: 10.1080/08958370802632267.
Cigarette smoke is a complex mixture of various toxic substances that are capable of initiating oxidative damage and promoting blood platelet alterations. In this study, we investigated the activities of the ectoenzymes NTPDase (ectonucleoside triphosphate diphosphohydrolase, CD39) and 5'-nucleotidase (CD73) in platelets as well as adenosine deaminase (ADA) in the plasma of rats exposed to aged and diluted sidestream smoke during 4 weeks. The rats were divided into two groups: I (control) and II (exposed to smoke). After the exposure period, blood was collected and the platelets and plasma were separated for enzymatic assay. The results demonstrated that NTPDase (with ATP as substrate) and 5'-nucleotidase (AMP as substrate) activities were significantly higher in group II (p < 0.05) as compared to group I, while no significant difference was observed for NTPDase with ADP as substrate. The ADA activity was significantly reduced in group II (p < 0.05) as compared with group I. Platelet aggregation was significantly increased in group II (p < 0.05) as compared with group I. We suggest that these alterations in the activity of enzymes from the purinergic system are associated with an increase in platelet aggregation. However, our study has demonstrated that the organism tries to compensate for this enhanced aggregation by increasing hydrolysis of AMP and reducing hydrolysis of adenosine, a potent inhibitor of aggregation and an important modulator of vascular tone.
香烟烟雾是多种有毒物质的复杂混合物，能够引发氧化损伤并促进血小板改变。在本研究中，我们调查了在4周内暴露于老化和稀释侧流烟雾的大鼠血小板中外切酶NTPDase（胞外核苷三磷酸二磷酸水解酶，CD39）和5'-核苷酸酶（CD73）的活性以及血浆中腺苷脱氨酶（ADA）的活性。大鼠分为两组：I组（对照组）和II组（暴露于烟雾组）。暴露期结束后，采集血液，分离血小板和血浆进行酶活性测定。结果表明，与I组相比，II组中以ATP为底物时NTPDase和以AMP为底物时5'-核苷酸酶的活性显著更高（p<0.05），而以ADP为底物时NTPDase未观察到显著差异。与I组相比，II组中ADA活性显著降低（p<0.05）。与I组相比，II组中血小板聚集显著增加（p<0.05）。我们认为，嘌呤能系统酶活性的这些改变与血小板聚集增加有关。然而，我们的研究表明，机体试图通过增加AMP的水解和减少腺苷（一种有效的聚集抑制剂和血管张力的重要调节剂）的水解来补偿这种增强的聚集。
