Extended Data Fig. 2: Histopathological evaluation of the nonhuman primate (NHP) brain at three months following a single IT dose of 60 mg C16-siRNA.
From: Expanding RNAi therapeutics to extrahepatic tissues with lipophilic conjugates
Representative H&E (a), LFB (b) and IBA-1 (c) staining of NHP brainstem (medulla oblongata region adjacent to aqueduct and underlying pons). Microscopic findings in the brain were limited to procedure-related changes (that is, CSF collection from cisterna magna). These consisted of minimal to mild degeneration of nerve fibers with dilated axonal sheaths and few digestion chambers containing gitter cells (arrowheads) that were localized to the peripheral white matter areas. Limited to procedure-affected areas, there were minimal decreases in LFB staining intensity (arrows) and a minimal increase in the number of IBA-1 (purple chromogen) positive microglia (open arrows). Three animals were analyzed per group with similar results.
