Abstract
Cigarette smoke consists of tar and gas phase: the latter is toxicologically important because it can pass through lung alveolar epithelium to enter the circulation. Here we attempt to establish a standard method for preparation of gas phase extract of cigarette smoke (CSE). CSE was prepared by continuously sucking cigarette smoke through a Cambridge filter to remove tar, followed by bubbling it into phosphate-buffered saline (PBS). An increase in dry weight of the filter was defined as tar weight. Characteristically, concentrations of CSEs were represented as virtual tar concentrations, assuming that tar on the filter was dissolved in PBS. CSEs prepared from smaller numbers of cigarettes (original tar concentrations ≤15 mg/ml) showed similar concentration-response curves for cytotoxicity versus virtual tar concentrations, but with CSEs from larger numbers (tar ≥20 mg/ml), the curves were shifted rightward. Accordingly, the cytotoxic activity was detected in PBS of the second reservoir downstream of the first one with larger numbers of cigarettes. CSEs prepared from various cigarette brands showed comparable concentration-response curves for cytotoxicity. Two types of CSEs prepared by continuous and puff smoking protocols were similar regarding concentration-response curves for cytotoxicity, pharmacology of their cytotoxicity, and concentrations of cytotoxic compounds. These data show that concentrations of CSEs expressed by virtual tar concentrations can be a reference value to normalize their cytotoxicity, irrespective of numbers of combusted cigarettes, cigarette brands and smoking protocols, if original tar concentrations are ≤15 mg/ml.
Highlights
Cigarette smoking is a major risk factor for cardiovascular diseases such as stroke and coronary artery disease [1,2], for chronic pulmonary obstructive diseases [3,4] and for several forms of cancer [5,6,7]
The concentration of cCSE was expressed in terms of the virtual tar concentration which was calculated on the assumption that the tar trapped on the Cambridge filter is dissolved in the phosphate-buffered saline (PBS) used for cCSE preparation
Validation of quantification of tar amount In the present study, we attempted to represent the concentration of the cCSE in terms of the virtual tar concentration which was calculated on the assumption that the tar phase trapped on the Cambridge filter is dissolved in the PBS (15 ml)
Summary
Cigarette smoking is a major risk factor for cardiovascular diseases such as stroke and coronary artery disease [1,2], for chronic pulmonary obstructive diseases [3,4] and for several forms of cancer [5,6,7]. Cigarette smoke is reported to contain more than 4,000 chemical compounds [8,9] Among these are reactive oxygen species (ROS) such as peroxynitrate and free radicals of organic compounds [1,10]. The gas phase extract contains stable toxic compounds which exert various cytotoxic effects in a wide range of cells [16,17,18] In this context, we have recently shown that the gas phase extract of cigarette smoke induces cell death and plasma membrane damage through ROS generation, which is in turn induced by protein kinase C (PKC)-mediated activation of NADPH oxidase (NOX) [19,20]. We have shown that like the gas phase extract, these stable cytotoxic compounds induce cell damage in a PKC- and NOX-dependent manner [20,23]
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call