There were 5 groups of rats in the study. Groups 2 through 5 were injured in a controlled operation. Groups 3 through 5 were given different dosage of laser therapy.
Group 1: No damage
Group 2: Damaged and then area treated with placebo
Group 3: Damaged and given non-optimal therapy
Group 4: Damaged and optimal dosage
Group 5: Damaged and non-optimal therapy
Any laser therapy showed a significant improvement over no laser and the optimal laser (Group 4 with a total dosage of 4 j/cm^2) showed no difference from the uninjured tissue. The image below show the group 2 and group 4 tissue under a polarization microscope.