Photodynamic treatment (PDT) causes a significant increase in the permeability of the blood-brain barrier (BBB) in healthy mice. Using different doses of laser radiation (635 nm, 10–40 J/cm2 ) and photosensitizer (5-aminolevulinic acid – 5-ALA, i.v.), we found the optimal PDT for the reversible opening of the BBB, exhibiting brain tissue recovery 3 days after PDT. Further increases in the laser radiation or 5-ALA doses have no amplifying effect on the BBB permeability, but are associated with severe damage of brain tissues.
