C3 and Parkinson disease: Astrocytes, the most abundant and widely distributed glial cells in the brain, form a crucial part of the microenvironment.[23, 31] Autopsy studies have found elevated expression of C3+ astrocytes in the pathological regions of PD brain tissue.[20, 23] In line with these findings, we observed a substantial presence of C3+ reactive astrocytes in the striatum of 6‐OHDA‐induced PD mouse models.