Blood-Brain Barrier Abnormalities Caused by HIV-1 gp120: Mechanistic and Therapeutic Implications
Figure 2
Gp120 is toxic to endothelial cells. (a) Human brain endothelial cells immunostained for occludin and incubated with 200 ng/mL gp120 became apoptotic. The nucleus was immunostained by 4′,6-diamidino-2-phenylindole (DAPI). Apoptotic cells were assayed by TUNEL. Numerous TUNEL-positive cells were observed after treatment with gp120 while almost no apoptotic cells were seen in cultures that were not incubated with gp120 ( serum-free media (control) versus 200 ng/mL gp120 in serum-free media for 24 hours). Almost all occludin-positive cells were TUNEL-positive for 200 ng/mL gp120. Control with buffer only and no enzyme showed no TUNEL staining (not shown). (b) Cryostat sections of rat CP injected with 500 ng gp120 1 hour earlier immunostained for CD31 and processed for TUNEL assay. Some of the endothelial cells, immunostained for CD31, are apoptotic and TUNEL-positive (arrows). Bars: (a) 50 μm; (b) 60 μm.
