Effect of α-MSH(11-13) on microglial activity.

<p>As a marker for cerebral inflammation microglial cells were quantified by staining for Iba-1. (<b>A+B</b>) Total amount of positive cells was counted in an ipsilateral and contralateral predefined window with no relevant difference between groups (ipsilateral: α-MSH(11-13) 25.44±4.85 cells/mm³ vs. vehicle 27.9±6.28 cells/mm³; contralateral: α-MSH(11-13) 25.44±4.26 cells/mm³ vs. vehicle 25.5±4.88 cells/mm³; each p = n.s.). (<b>C</b>) In series Iba-1 positive cells were categorized in cells with 0 up to 6 branches. (<b>C</b>) The ratio of branched cells to total cell number in contralateral brain tissue is nearly adapted between treatment groups. (<b>E</b>) Counting of branches of ipsilateral tissue categorized into 0–1, 2, and >2 branches and summarized as mean (number of branched cells/total cell number [%]) illustrated a less activated status of microglia after α-MSH(11-13) administration compared to vehicle. Numeric data are shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0071056#pone-0071056-t003" target="_blank"><b>Table 3</b></a>. Considering cells with one or no branch as activated, there was a lesser degree of activation in the α-MSH(11-13) treated group indicating a reduced inflammatory state (α-MSH(11-13) 7.78±8.76% vs. vehicle 17.87±9.65%, p = 0.033). Relating to cells with a maximum of two branches as activated cells, the difference was even more evident (α-MSH(11-13) 21.92±13.05% vs. vehicle 47.65±14.1%, p = 0.002; numeric data presented as mean ± S.D. are shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0071056#pone-0071056-t004" target="_blank"><b>Table 4</b></a>). As this is an explorative study p-values are given for descriptive reasons only.