Figure 5.

PAR effects in mouse organotypic OS model. Mouse OS tumor sections in floating culture were treated with PAR at increasing treatment times (10, 15 and 20 min) or by 100 µM of Cisplatin (CIS) or 500 µM of H₂O₂. (A) Metabolic activity was determined by resazurin 24 and 72 h after PAR exposure. In this assay, four sections were analyzed per condition, and the assay was performed in three independent experiments. Values were relativized to tumor sections exposed to untreated PAR. Tumor sections were fixed 72 h after treatment and processed for histological analysis. Samples were stained with haematoxylin/eosin (HE) and immunostained for Ki-67. (B) HE quantification of positive nuclei stained areas (values relativized to control). (C) Percentage of positive Ki-67 stained nuclei. For statistical analysis, 5 well-distributed images were taken at X40 and were analyzed. Asterisks represent statistically significance between different conditions (n = 3; * p-value < 0.05; *** p-value < 0.005; ANOVA and two-sided Student’s t-test). (D) Representative images for HE and Ki-67 immunostaining for each condition (Scale bar = 120 µm).