Fig. 2

Chronic oxycodone treatment induces biomarkers of oxidative and nitrosidative stresses. a. Immunohistochemical analysis of oxidized DNA in nucleus accumbens (NuAcc), cortex, and brain stem of rats treated with water (W) or oxycodone (O). Tissues were stained with antibodies against 8-Hydroxyguanosine (8H). Representative images of area next to anterior commissure (ac) in NuAcc, striatum in cortex area, cerebellum in brain stem area. Scale bar denotes: NuAcc, 100 μm; Cortex, 50 μm; Stem, 20 μm. Below the images is statistical analysis of the data. Open bars water samples; gray filled bars oxycodone samples. The intensity of 8H-Ab stating in nucleus accumbens, cortex, and cerebellum was analyzed using MeanQ method. The graphs represent the mean value of signal in three different animals (±SEM). Data was analyzed by Student’s t test. NuAcc, n = 9 fields in water and n = 6 fields in oxycodone samples containing 9–19 cells each, p < 0.001. Cortex, n = 9 fields in water and n = 5 fields in oxycodone samples containing 6–18 cells each, p < 0.001. Stem, n = 5 fields in water and n = 5 fields in oxycodone cerebellums containing 23–51 cells each, p < 0.001. b Dot-blot analysis of lysates from nucleus accumbens, cortex, and brain stem of rats treated with water (W) or oxycodone (O1, O2). Two μg of total proteins were spotted on NC membrane and then probed with antibodies against either nitro-tyrosine (3N left membrane) or actin (right membrane). The 3N signal was normalized to the corresponding actin signal in each sample and then oxycodone data was normalized to the corresponding water data. The graph represents the mean ratio of oxycodone to water data obtained in three separate experiments using lysates from different drug administration experiments (±SEM). Data was analyzed by Student’s t test. NuAcc, nucleus accumbens, p < 0.05; Cortex, p < 0.05; Stem, brain stem, p < 0.05. Open bars water samples; gray filled bars oxycodone samples