Figure 1. SU5416 prevents MPP⁺-induced apoptosis in a concentration-dependent manner.

(A) SU5416, but not VRI, prevented MPP⁺-induced cell death in a concentration-dependent manner. CGNs were treated with SU5416, VRI, EPTU, 7-nitroindazole (7-NI), 1400 W or DMSO (vehicle control) at the indicated concentrations for 2 hours and then exposed to 35 µM MPP⁺. Cell viability was measured by MTT assay at 24 hours after MPP⁺ challenge. (B) SU5416 blocked neuronal loss induced by MPP⁺. CGNs were pre-incubated with or without 20 µM SU5416 and exposed to 35 µM MPP⁺2 hours later. At 24 hour after MPP⁺ challenge, CGNs were assayed with FDA/PI double staining. (C) SU5416 reversed the morphological alteration induced by MPP⁺. CGNs were pre-incubated with or without 20 µM SU5416 and exposed to 35 µM MPP⁺2 hours later. At 24 hour after MPP⁺ challenge, CGNs were assayed with nNOS and Hoechst double staining. (D) The number of apoptotic nuclei with condensed chromatin was counted from representative Hoechst staining photomicrographs and represented as a percentage of the total number of nuclei counted. Data, expressed as percentage of control, were the mean ± SEM of three separate experiments; *p<0.05 and **p<0.01 versus MPP⁺ group in (A) or versus control in (D); ^## p<0.01 versus MPP⁺ group in (D) (Turkey’s test).