Induction of apoptosis at the molecular genetic level exposed to lead oxide nanoparticles in a chronic animal experiment

Abstract

Introduction. Workers of industrial enterprises and the population living nearby are at risk of lead poisoning. Lead exposure can lead to irreversible negative consequences for the body, including hepatic and renal dysfunction, hematopoietic damage, cognitive dysfunction, and impairment of the genetic apparatus of the human cell. In this regard, it is necessary to study characteristics of the toxic effect of lead oxide nanoparticles (PbO NPs) to determine their health effects and minimize related disorders and diseases.
 The purpose of the study was to determine the level of expression of the BAX, BCL-2, P53, GSTM1, GSTP1, and SOD2 genes in various organs of laboratory rats following the exposure to lead oxide nanoparticles.
 Materials and methods. Twenty mature female albino Wistar rats were used in a four month experiment with chronic inhalation exposure to PbO NPs, 10 animals per group (exposure and control). The mean concentration of PbO NPs in the inhaled air was 0.215 mg/m3. At the end of the exposure period, organ fragments from the decapitated animals were fixed in liquid nitrogen and subsequently stored in a freezer at –80 °C. Total RNA was isolated from tissues using the ExtractRNA reagent. The expression level was determined by quantitative reverse transcription real-time PCR.
 Results. The BAX expression in the liver of rats exposed to PbO NPs for 4 months was by 2.2 times higher than in the control group (p=0.009). We observed a trend towards an increase in the BAX/BCL-2 ratio in hepatocytes indicating apoptotic processes. The P53 expression level was by 1.4 times higher in the olfactory bulb of the exposed rats (p=0.025) when compared to the controls. No changes were found in the expression levels of antioxidant genes GSTM1, GSTP1, and SOD2.
 Limitations. The study was conducted using female Wistar rats with no potential sex differences taken into account.
 Conclusion. Chronic inhalation exposure to PbO NPs induces apoptosis in rat liver through the BAX/BCL-2 pathway and rat brain through the regulation of P53.