Minocycline reduces microglial activation, assessed by ionized calcium binding adaptor molecule 1 (IBA-1) expression.

(A) IBA-1 expression in four representative sections from each of an uninfected, CD8-depleted animal (control), an untreated SIV-infected CD8-depleted animal (1308), a MN-treated persistently CD8-depleted animal (7307) and a MN-treated short-term CD8-depleted animal (7407). Visual inspection reveals less IBA-1 expression in the MN-treated animals. (B) Immunohistochemistry image analysis for IBA-1 in brain tissue sections of the frontal cortex. Data is given for four uninfected, CD8-depleted animals which served as controls (diamonds), four untreated SIV-infected CD8-depleted animals sacrificed at 8 wpi (solid squares) and four minocycline (MN)-treated (persistently CD8-depleted) animals. The mean for each cohort is given as a horizontal black line within its respective box. Upper and lower boundaries of the boxes correspond to a factor of 1.5 times the standard deviation. There was a statistically significant difference in frontal cortex IBA-1 levels among the three cohorts (p = 0.012). There are more IBA-1 positive particles/mm² in the SIV-infected, CD8-depleted, untreated cohort compared to -uninfected, CD8-depleted controls (p = 0.004). There was no statistically significant difference in IBA-1 positive particles/mm² in MN-treated animals compared to the uninfected CD8-depleted controls.