Fig. 4.

Effect of rotenone on microglial activation. Mixed neuron/glia cultures were treated for 1 d with the vehicle or 1–10 nm rotenone and then were immunostained with antibodies against specific markers of microglia. A, Immunocytochemical analysis with the OX-42 antibody of cultures treated for 1 d with the vehicle or 10 nm rotenone. In control cultures a significant portion of the OX-IR resting microglia was small and round (open arrowheads). After treatment with 10 nm rotenone, OX-42-IR microglia were enlarged significantly and were irregularly shaped (filled arrowheads), indicative of activation. Part of the images of OX-42-IR microglia (inclosed boxes, a and b) presented in A was cut out and presented inB for better representation of the differences.C, Quantification of microglial activation. Vehicle or rotenone-treated cultures were immunostained with OX-42, ED-1, or isolectin; positively stained microglia were counted. The number of OX-42-IR microglia in the control cultures was ∼120/mm². The results are expressed as a percentage of the control cultures and are the mean ± SEM of three experiments performed in triplicate. *p< 0.01, compared with the control. Scale bar, 50 μm.