Cigarette Smoke Extract Produces Superoxide in Aqueous Media by Reacting with Bicarbonate.

Jung-Min Park,Kyuhong Lee,Won Jun Choi,Seong-Jin Choi,Yoon-Seok Seo,Moo-Yeol Lee,Van Quan Do,Haerin Jeong,Kyung-Chul Choi

doi:10.3390/toxics9110316

Abstract

The toxicity of cigarette smoke (CS) is largely attributed to its ability to generate reactive oxygen species (ROS). Reportedly, CS generates superoxide in cell culture systems by stimulating the cells to produce superoxide and through direct chemical reactions with components of the culture media. In this study, we investigated CS-induced superoxide formation in biocompatible aqueous media and its characteristics. Cigarette smoke extract (CSE) and total particulate matter (TPM) were prepared from the mainstream smoke of 3R4F reference cigarettes. CSE and TPM generated superoxide in Hank’s balanced salt solution (HBSS), Dulbecco’s modified Eagle media (DMEM), and blood plasma, but not in distilled water and phosphate-buffered saline. Each constituent of HBSS in solution was tested, and bicarbonate was found to be responsible for the superoxide generation. More than half of the superoxide formation was abolished by pretreating CSE or TPM with peroxidase, indicating that the substrates of peroxidase, presumably peroxides and peroxy acids, mainly contributed to the superoxide production. In conclusion, the presence of bicarbonate in experimental conditions should be considered carefully in studies of the biological activity of CS. Furthermore, the local amount of bicarbonate in exposed tissues may be a determinant of tissue sensitivity to oxidative damage by CS.

Highlights

Smoking is a well-established risk factor for cardiovascular diseases, cancers, and respiratory disorders
With and without Fetal bovine serum (FBS), and blood plasma, whereas superoxide generation was minimal in distilled water (DW) and phosphate-buffered saline (PBS) (Figure 1A)
Superoxide production was proportional to the concentration of Cigarette smoke extract (CSE) up to at least 10% in Dulbecco’s modified Eagle media (DMEM) (Figure 1B)

Summary

Introduction

Smoking is a well-established risk factor for cardiovascular diseases, cancers, and respiratory disorders. Several studies conducted over the past few decades have uncovered smoking-activated pathogenic events, key aspects of which include cytotoxicity and altered cell growth, inflammation, genetic damage, hypoxia, cardiac and endothelial dysfunction, prothrombotic condition, and abnormal lipid accumulation [1]. The detailed mechanisms have not been fully elucidated, the multiple molecular factors of biological systems and a variety of chemicals in cigarette smoke (CS) must be implicated in these processes. This is all the more likely considering the complexity of the signaling pathways leading to these events and the more than 4000 chemical constituents in CS [2]. CS is known to stimulate ROS production in cells by activating ROS sources, such as NADPH oxidase and mitochondria [6,7]

Methods

Results

Conclusion