Fig 2. Effect of Tβ4 peptide on H₂O₂-induced cytotoxicity (A), Tβ4, inducible nitric oxide (NO) synthase (iNOS) and cyclooxygenase-2 (COX-2) mRNA and protein expressions (B, C), NO and prostaglandin E₂ (PGE₂) secretion (D, E) in PDLCs.

Cells were pretreated with indicated concentrations of Tβ4 peptide for 2 hours and then incubated with 200 μM H₂O₂ for 48 hours (A-E). Cell viability was measured by MTT assay (A). Protein and mRNA expressions were assessed by RT-PCR (B) and Western blot analysis (C), respectively. The production of NO (D) and PGE₂ (E) were measured by Griess reaction and ELISA, respectively. Data replicated the quantifications of cytotoxicity, NO, and PGE₂ with the standard deviation of at least three experiments (n = 4). The bar graph shows the fold increase in protein or mRNA expression compared with control cells. * Statistically significant differences compared with the control, p<0.05. # Statistically significant difference compared with the H₂O₂—treated group.