Figure 3.

LITT increases BBB and BTB permeability to large molecules. (A) Animals treated with LITT were injected intravenously with 70 kDa dextran on post-laser day 3, and brains harvested and processed for immunofluorescence to assess dextran penetration. Representative images are shown (n = 3 for each condition). Scale bar = 100 µm; scale bar for magnified images = 300 µm. (B) Mice with stereotactically injected RFP-expressing GL261 cells were treated with LITT 10 days after implantation and injected intravenously with 70 kDa dextran on post-LITT day 3. Brains were processed as in A. Representative images are shown (n = 3 for each condition). (C) Mice treated with LITT as in A were injected intravenously with human IgG on post-laser day 3, and brains processed to assess IgG tissue penetration. Representative images are shown (n = 3 for each condition). (D) Tumor-bearing mice as in B were treated with LITT 10 days after implantation and injected intravenously with human IgG on post-LITT day 3. Brains were processed as in C. Representative images are shown (n = 3 for each condition). (E) Brain permeability of 70 kDa dextran and human IgG in LITT- and sham-treated brain was quantified by mean pixel intensity of fluorescence divided by area (µm²). Data represent mean ± SEM. LITT significantly increased penetration of 70 kDa dextran and human IgG compared to sham (n = 3 for each condition, t-test, *P < .01, **P < .001). (F) Brain tumor permeability of 70 kDa dextran and human IgG in laser- and sham-treated brain was quantified by mean pixel intensity of fluorescence divided by area (µm²). Data represent mean ± SEM. Laser treatment significantly increased tumor penetration of 70 kDa dextran and human IgG (n = 3 for each condition, t-test, *P < .05, **P < .01). (G) NOD-SCIDγ mice were stereotactically injected with MGG8 human glioblastoma cells and subjected to sham or laser treatment 10 days after implantation. Animals were injected intravenously with human IgG on post-laser day 3, and brains processed with immunofluorescence to assess IgG tissue penetration. Representative images are shown (n = 2 for each condition). DAPI = nuclear stain. Scale bar = 100 μm. Magnified image scale bar = 400 μm. (H) Tissue was processed as in D and BTB permeability quantified as in F for MGG8 tumor-bearing mice. Data represent mean ± SEM. Laser treatment significantly increased tumor penetration of human IgG (n = 3 for each condition, t-test, **P < .002).