Terbufós (Organofosforado) em dípteros de importância forense: uma abordagem biológica e bioespectroscópica

Abstract

Entomotoxicology studies the effect and detection of chemical substances in insects of medico-legal, agricultural and environmental importance, being crucial for the correct estimation of the interval and causes of death of decaying carcasses and cadavers, as well as monitoring and control of toxicant use. Among substances of medico-legal importance, Terbufos (Organophosphate) is frequently associated with intoxication cases in Brazil and worldwide. Thus, this study aims to understand the effect of Terbufos: i. in carrion decomposition and assemblage of sarcosaprophagous dipterans associated with carcasses intoxicated with different doses of the compound; ii. in the carcass colonization process and its implications for the calculation of the minimal postmortem interval (mPMI); iii. in movement and mobility behavior of scavengers and its implications as entomological evidence, as well as iv. evaluate the mid-infrared (ATR-FTIR) spectroscopy with multivariate analysis as an alternative to detect poisoning by Terbufos in larvae from intoxicated rats. For this, female Wistar rats received, via gavage, 200 µL of Terbufos (5 mg/kg, 10 mg/kg or 20 mg/kg) or distilled water (control) and, after 30 minutes, were euthanized and distributed in suspended traps to decompose into environmental conditions. The decomposition was monitored daily, with photographic record and collection of visiting and colonizing dipterofauna until the dry phase. The dispersing larvae were also used for behavior analysis and spectra collection. The data collected showed that Terbufos accelerates the decomposition of carcasses intoxicated with 10 mg/kg in 24h, and changes the composition and structure of the visiting and colonizing dipterofauna, and the behavior of immature intoxicated with high doses of Terbufos. In addition, the ATR-FTIR with multivariate analysis differentiated the intoxicated and control groups through protein phosphorylation, phosphate stretch and protein groups, especially when the GA-LDA model was used. Through a multidisciplinary approach, this study strengthens the importance of entomotoxicological studies to evaluate entomological evidences and can assist in investigative processes with suspected organophosphate poisoning.