Microglial density in the ventral midbrain. Photomicrographs of activated microglia immunohistochemistry in a representative midbrain section of a vehicle (A, B) and a COXIB (C, D) treated animal 21 days after the injection of 6-OHDA. E, F) Bar graphs showing the stereological quantification of activated microglia cell density at 12 (E) and 21 days (F). Microglial density was significantly reduced in the ventral midbrain of COXIB treated rats (treatment effect F= 6.28, p < 0.05) both in the lesioned and in the contralateral striata. Microglial density was higher at 21 days in all groups and was significantly higher in the vehicle group ipsilateral to the lesion (p < 0.05). Scale bar: 25 μm.