Fig. 2.

NPD1 attenuates oxidative-stress-induced apoptosis. (A) BSA–DHA enhanced NPD1 synthesis and led to decreased apoptosis. After plating, cells incubated for 72 h in the presence of either BSA (3.35 μM) or BSA plus DHA (6.7 μM). Then the cells were serum-starved for 1 h and TNF-α/H₂O₂ was added (14 h). Cells pretreated with BSA plus DHA yielded marked attenuation of Hoechst-positive cells. (B) NPD1 (50 nM) attenuated oxidative-stress-induced Hoechst-positive staining. After plating (72 h), cells were serum-starved for 8 h, TNF-α/H₂O₂ was added, and the cells were further incubated for 14 h and then stained with Hoechst reagent. The 800 and 400 μM refer to H₂O₂ concentrations. (C) Lack of inhibition by 50 nM prostaglandin E₂, LTB₄, or 20-OH-LTB₄ of oxidative-stress-induced or Hoechst-positive staining. (D) DHA (50 nM) added as a free acid inhibited oxidative-stress-induced Hoechst-positive staining. Arachidonic acid (50 nM) exhibited far less protection. In C and D, 800 μM H₂O₂ was used; other conditions were as in B. (E) Synthesis of NPD1 in cultures exposed to DHA (50 nM) as in D. The pool size of free DHA is shown by blue bars.