Fig. 6. Postnatal day 5 wild-type or p75^NTRknockout mice were given an intraperitoneal (intraperitoneal) injection of propofol (100 mg/kg) or intralipid for 6 h and apoptosis was evaluated by cleaved caspase-3 immunofluorescence. (A ) Dentate gyrus, CA3, and CA1 regions of the hippocampus are indicated on image. Basal TAT-CTRL, Basal TAT-Pep5, propofol TAT-CTRL, and propofol TAT-Pep5 are indicated on the image. Immunofluorescence microscopic analysis shows that wild-type mice exhibited a significant increase in cleaved caspase-3 in the dentate gyrus (*P = 0.002), CA3 (*P = 0.008), and CA1 (*P = 0.007) regions of the hippocampus compared with intralipid-treated controls (n = 4 or 5). TAT-Pep5 (10 μM, 15 min) significantly attenuated propofol-mediated apoptosis (*P = 0.005, CA1; *P = 0.002, CA3; *P = 0.004, dentate gyrus). (B ) Additional immunofluorescence microscopic analysis shows that p75^NTRknockout mice exhibited no increase in cleaved caspase-3 in the dentate gyrus, CA3, or CA1 following propofol exposure compared to wild-type (#P = 0.0008, dentate gyrus; #P = 0.03, CA3; #P = 0.002, CA1). Quantitation of the data are represented in the graphs. Sample size is indicated above the error bars ± SEM. Scale bar = 20 μm. Cl-Csp3 = cleaved caspase-3; DAPI = 4′,6-diamidino-2-phenylindole; DG = dentate gyrus; KO = knockout.