Figure 5

Biosafety of tested microparticles in vivo. Chitosan microparticles (CHI), chitosan microparticles with Pluronic F-127 (CHI-Pluronic), chitosan microparticles with N-Acetyl-d-Glucosamine (CHI-GlcNAc) were used. Guinea pigs were injected subcutaneously with tested CHI MPs or 0.85% NaCl and observed for the development of deleterious skin reactions (A). Edema and erythema were examined and graded daily according to the Primary Irritation Index (PII) = 0/3, negligible irritation—0. After 72 h after injection of MPs the animals underwent euthanasia, for isolation of spleen, liver and blood samples (B). Splenocytes were tested for proliferation activity in the presence of positive control (PC)—phytohemagglutinin (PHA) by (³H)-thymidine incorporation assay. Stimulation index (SI) was assessed: radioactivity counts (cpm/min) of cells treated with CHI-MPs/radioactivity of untreated cells. (C) The level of alanine aminotransferase ALT (a) or aspartate aminotransferase AST (b) in homogenized liver tissue or serum (c,d); the level of tumor necrosis factor-alpha—TNF-α (e) and interleukin (IL)-1ß (f) in serum (ELISA). Five animals were in the group. The results are shown as median ± range.