Carboxylesterase Concentration in Mouse Exposed to Particulate Matters on Inhalation Exposure of Prallethrin and d-Phenothrin Mixture

Abstract

CE enzyme applied critical hydrolysis of pyrethroid families such as prallethrin and d-phenothrin, this active ingredient was commonly contained in mosquito repellent (MR). The previous study found that MRs as particulate matters (PMs) were very hazardous for living organisms due to the characteristics of number and mass concentration. This study examined the CE concentration in Mus musculus exposed to PM on inhalation exposure of prallethrin and d-phenothrin mixture. The lower dose was a mixture of 0.000141 mg/L prallethrin and 0.104 mg/L d-phenothrin, while the higher dose was a mixture of 0.00141 mg/L prallethrin and 1.04 mg/L d-phenothrin. Prallethrin and d-phenothrin were dissolved in acetonitrile, then diluted several times to obtain the preferred concentration. The solution was inflated with air through a diffuser to generate PMs which inserted into the chamber contained mice. The experimental group was divided into three, namely: positive control (PC), and lower- and higher-dose treatment groups, with three replicates for each group. The results illustrate that lower and higher dose demonstrated major differences. The statistical analysis confirmed that CE concentration had significant differences between groups. The increase in pyrethroid concentration followed by the increase of CE concentration, It indicated that the increasing CE substrates would be followed by the increasing of protein synthesis including CE. PMs in terms of number concentration of the largest (particles/L) is 0.3 µm, followed by 0.5 µm, 1 µm, and 5 µm. Approximately 99.86 % of the mass concentration the breathing zone is contributed by respirable particles (fine and ultrafine particles). Even if ultrafine particles are the largest number concentration, they have no significant contributions to the mass. A very abundant of fine and ultrafine particles affects they were beyond detection limit instruments, thus, they have no significant relationship with CE concentration, even though number concentration is more prominent than the mass concentration in the toxicological field, due to the high surface area of ultrafine particles.