Fig 4. Chronic treatment with photobiomodulation suppresses α-syn-induced dopaminergic neuronal loss.

(A) Photomicrographs illustrating dopaminergic (TH+) neuronal loss in the injected substantia nigra. The slices were stained using the anti-TH antibody and the signal revealed a reduction in TH+ immunoreactivity in the injected midbrain (* injected side), compared to the non-injected side. In the treated groups, the immunostaining showed less TH+ signal loss in the injected side, compared to the non-treated animals. Scale bar = 300 μm. (B) Unbiased stereological quantification of TH+ neurons in the injected side (as % of the contralateral side). Comparison with the non-injected side revealed a dramatic neuronal loss in the SNc after human α-syn overexpression (35% of cell loss). Interestingly, comparison of the dopaminergic cell loss in the treated conditions showed less neuronal degeneration, with a significant effect seen only with the fluence rate of 5mW/cm² (## p<0.01, Tukey’s test).