Figure 4. The catalase inhibitor 3-aminotriazole (3AT) inhibits the protective effect of adenoviral catalase gene transfer.

Cultured cortical neurons were incubated with either the Ad5CMVcatalase (Catalase) or with the Ad5CMVntLacZ (LacZ) vector (2 plaque forming units/cell) in the regular cell culture medium. After 24 h the cultures were rinsed and the cells were exposed to50 μM H₂O₂ and 1 U/ml glucose oxidase for 60 min in Neurobasal medium. To block catalase activity, the cultures were treated with increasing doses of 3AT 10 min prior to and during H₂O₂ exposure. Cell viability was measured 24 h after the challenge and was expressed as percent of the viability of control cultures which were not infected with the any of the vectors and were not exposed to H₂O₂. *Significant difference (p < 0.05) compared with untreated control. #Significant difference (p < 0.05) compared with the corresponding cultures infected using the Ad5CMVntLacZ. Data are expressed as mean ± SEM; cells from at least two individual cultures; n = 16 in each group.