Fig. 4.

Effect of DAO and histamine on MTT activity as value of cell viability. Cells were cultured in the presence of FBS for 7 (a) or 21 days (b) and were then exposed for 24 h to 2.75 or 8.5 mM histamine, alone (black columns) or in the presence of 0.77 mg/mL DAO with or without 0.77 mg/mL catalase. Cells were exposed to DAO (± CAT) 10 min prior to the addition of histamine or were exposed to a mixture of DAO and histamine (with and without catalase) preincubated for 2 h at 37 °C before use for cell treatment. Data shown are mean ± SD estimated on three to six independent cell cultures. Columns labeled with different letters are significantly different (p ≤ 0.05)