Treatment with RSV reduced IL-6 and IL-8 secretion levels in OS cell lines. The ELISA assay results showed how IL-6 (A) and IL-8 (B) levels (pg/mL) decreased after 48-h RSV treatment (mean ± SD). Baseline expression of this proinflammatory cytokine was different in each OS cell line, but the decrease in IL-6 levels was observed for each OS cell line. A one-way ANOVA test was used to evaluate the effect of RSV treatment factor (60 and 120 µM) on IL-6 release (MG-63—F = 27.4, p < 0.0005; Saos-2—F = 34.7, p < 0.0005; KHOS—F= 53.6, p < 0.0005; U-2 OS—F = 24.3, p < 0.0005) and on IL-8 (MG-63—F = 583, p < 0.0005; Saos-2—F = 315, p < 0.0005; KHOS—F = 155, p < 0.0005; U-2 OS—F = 102, p < 0.0005). Dunnett’s test: *, p < 0.05, **, p < 0.005, ***, p < 0.0005 versus untreated cell culture.