Abstract
The purpose of this study was to obtain scientific information regarding classification and health hazards that may result from a 13 weeks inhalation exposure of isoprene in Sprague-Dawley (SD) rats. The testing method was conducted in accordance with OECD guidelines for the testing of chemicals No. 413. The Rats were divided into 4 groups (10 male and 10 female rats in each group) and exposed to 0, 360, 1,620, 7,300 ppm isoprene in each exposure chamber for 6 h/day, 5 days/week, for 13 weeks. As a result, there were no mortality or abnormality during the period of study and did not show any significant changes of body weight. There were no dose response changes in urinalysis, hematological and serum biochemical value examination. Relative organ weight was increased significantly the right kidney in 7,300 ppm group of male rats. In female rats, relative organ weight of the left kidney and the both lungs in 1,620 ppm group and the left lung and the both kidneys in 7,300 ppm group were increased significantly. But the histopathological findings did not reveal any exposure-related changes. According to the above results, the no observable adverse effect level (NOAEL) of isoprene was 7,300 ppm (20.3 mg/L) in both male and female rats. In conclusion, Isoprene was not classified specific target organ toxicity of the 'Standard for Classification and Labeling of Chemical Substance and Material Safety Data Sheet' (Ministry of Employment and Labor, 2009).
