DOSE-EFFECT OF THE ALUMINA NANOINSECTICIDE ?NSA? ON THP-1 MACROPHAGE CELL CULTURES

POCHETTINO, A; D´ATILLIO, L; BONGIOVANNI, B; KONJUH, C; BAY, ML; STADLER, T

Rosario

Encuentro; 2º Reunión Internacional de Ciencias Farmacéuticas; 2012

Universidad Nac. Rosario

Introduction The discovery of the alumina nanoinsecticide ?NSA? opens new frontiers in pest management with inorganic powders [1]; nevertheless, the assessment of the toxicity of this new product is a must to approve its use in agriculture and as an indoor pesticide. Wagner, A. et al (2007), showed that in vitro cytotoxicity of different types of aluminum nanoparticles (AN) on alveolar macrophage cells depends on the particle chemistry. Other authors demonstrated that AN (Al) triggers a decrease in cell viability and phagocytic ability, but this phenomenon is not evident in macrophage cell cultures exposed to Al2O3 nanoparticles [2]. Furthermore, there is some evidence on the immunomodulatory properties of different nanoparticles [3, 4], and therefore it?s reasonable to assume that alveolar macrophages which are capable of NSA phagocytose would also show altered responsiveness against different microbial pathogens. Objective To evaluate in vitro the effect of the NSA on macrophages from the THP-1 cell line, exposed during two different time periods (6 and 24 hours) to different NSA concentrations (5, 25, 100 and 250 ìg/mL) Matherial and Methods Cell viability (MTT test) [5], proliferative capacity (incorporation of [3H] thymidine), cytotoxicity (LDH), IL-1â (ELISA), catalase activity (CAT) [6], total thiol (-SH) groups [7] and cell morphology by immunofluorescence microscopy (IFM) [8] were determined. Results Cell cultures exposed to the lower concentrations of NSA during 6 hours show increased levels of IL-1â (5ìg/ml=4 times, p<0,03 y 25ìg/ml=11 times, p<0,02) and a significant reduction of CAT (5ìg/ml=18%, p<0,03 y 25ìg/ml=32%, p<0,02) compared with the untreated control. In contrast, the cell cultures exposed to the two highest NSA concentrations induced a decrease in cell viability (p<0,002) and an increase in LDH (e.g. 250ìg/ml=60 times, p<0,001) and IL-1â (e.g. 250ìg/ml=200 times, p<0,002) release, while the CAT activity (e.g. 250ìg/ml=60%, p<0,001) and ?SH (e.g. 250ìg/ml=40%) diminish. After NSA treatment, mitochondria lost their filamentous shape and displayed several morphological alterations. The effect of NSA on cell cultures after 24 hours of exposure was similar to that observed at 6 hours Discusion The exposure of THP-1 macrophage cell cultures to high NSA concentrations induces the release of IL-1â but also causes cell death, where NSA mediated oxidative stress could play an important role. On the other hand, low NSA concentrations raise the IL-1â levels without inducing changes in cell viability; so, this could be of relevance to enhance triggering immune responses. These results motivate further research on the mechanisms underlying the observed effects of NSA on THP-1 macrophage cells, as well as to analyze other mediators and immunological parameters in order to evaluate the potential of the NSA as a modulator of the immune response.