Fig. 4. Western blot analysis demonstrating caspase-3 activation in astroglial cells induced by SIN-1 (1, 2, and 3 mm) ( A ) and propofol (40 μm, 80 μm, 160 μm, and 1 mm) or Intralipid exposure ( B ). Astrocytes were exposed to SIN-1 (3 mm) for 18 h in the presence or absence of propofol (40 μm, 80 μm, 160 μm, and 1 mm) or Intralipid ( C ). The activation of caspase-3 was assessed by the presence of a 17-kd fragment derived from the cleavage of proenzyme caspase-3. Immunoblots are representative of four independent experiments. SnMP = tin mesoporphyrin.