Figure 4

DHA promotes the formation of small LBs, increases LB interaction with mitochondria and restores mitochondrial function in microglia from both N9 and hippocampal slice cultures. A Fluorescent labeling of LBs and mitochondria in N9 cultures reveals that LBs are in close proximity with mitochondria under control and DHA-treated cultures but not in LPS-treated cultures. With DHA treatment, the LBs appear to form in large clusters. Scale bar 10 μm. B MTT assay detection of mitochondrial metabolic activity expressed as percentage of control-treated cultures. With 24 h of LPS treatment, there is a significant decrease in mitochondrial metabolic activity. With the addition of DHA alone, there is an increase in mitochondrial metabolic activity compared to control cultures. Lastly, when the cultures are treated with both LPS and DHA, the mitochondrial metabolic activity is restored to 100% of control. *p < 0.05. C Fluorescent labeling of LBs, mitochondria and activated microglia in hippocampal slice cultures revealed that LBs are in close proximity with mitochondria under control and DHA-treated cultures but not in LPS-treated cultures. With DHA treatment, the LBs appear to form in large clusters, similar to the findings reported in N9 cultures. Scale bar 20 μm. D JC-1 staining of mitochondrial membrane depolarization can be used as readout of mitochondrial health seen by a shift in the red/green fluorescence ratio in hippocampal slice cultures. The 24-h treatment with LPS significantly decreases the red/green ratio, an indication of mitochondrial depolarization and poor mitochondrial health. With the addition of DHA, the red/green fluorescence ratio is restored to control level. *p < 0.05.