Concerning the manuscript 'Burnt sugarcane harvesting: Particulate matter exposure and the effects on lung function, oxidative stress, and urinary 1-hydroxypyrene'

摘要

The article of Prado et al. (2012) presents a comparative analysis of the human exposure to particulate matter (PM) before and after harvesting of a sugarcane field. In this study, authors evaluated lung function (in addition to respiratory symptoms and oxidative stress) not only among sugarcane workers but also among the inhabitants of a town next to the sugarcane fields. The increase in the concentration of ambient PM was a result of burning of the sugarcane field during harvesting. The parameters used to evaluate oxidative stress included GPx, GST, SOD, and CAT activities, in exposed subjects. However, we are concerned about the discussion presented in the paper especially that of the antioxidants including GR; GPx is not sufficient to explain the phenomenal change in their activities. Moreover, the result of CAT analyses was significantly different in cohort before and after harvesting (p ＜ 0.05), but there is no a single sentence in the discussion to elaborate this observation. In human, CAT is a part of the primary enzymatic exogenous antioxidant defense system (Carocho and Ferreira, 2013). As an adaptive response, the up-regulation of CAT is an important event during oxidative stress, particularly in the case of overproduction of H_2O_2 (Hernandez et al., 2013). PAH-induced CAT activity is reported by Singh et al.