Biphalin, a Dimeric Enkephalin, Alleviates LPS-Induced Activation in Rat Primary Microglial Cultures in Opioid Receptor-Dependent and Receptor-Independent Manners

Figure 8

The influence of biphalin on MOP (a) protein levels in vehicle- and LPS-treated primary microglial cells and the immunocytochemical localization of MOP (b). (a) Microglial cells were treated with biphalin (BIPH; 10 μM) for 30 min and then with LPS (100 ng/mL) 24 h. Naloxone (NLX; 0.1 μM) was added 30 min before biphalin. The data are presented as the fold change compared with the control group (vehicle-treated cells) as the mean ± SEM of 4 independent experiments. The results were statistically evaluated using one-way analysis of variance (ANOVA) followed by Bonferroni’s post hoc test to assess the differences between the treatment groups. Significant differences in comparison with those of the control group (vehicle-treated cells) are indicated by ; differences between LPS-treated and biphalin- or biphalin- and naloxone-treated cells are indicated by ^#; differences between biphalin-treated and biphalin- and naloxone-treated cells are indicated by ^$. (b) The presence of MOP in microglia was confirmed by double immunofluorescence. We found that MOP receptor (red) and OX-42 (a marker of microglial cells; green) were colocalized. The scale bar for all microphotographs is 25 μm.

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