Chitosan is a nontoxic, antibacterial, biodegradable, and biocompatible biopolymer. It has been widely used in food and biomaterial industries as weight-loss aids, cholesterol-lowering agents, and medical devices, such as bio-scaffolds for tissue engineering, wound healing products, and haemostatic bandages [1], [3]–[8]. Although chitosan is usually administered by an oral route as a dietary supplement, food additive, or oral drug delivery, chitosan would be degraded by gut microflora or influence the distribution and number of gut microflora by oral administration [1], [2], [34]. Therefore, we administered transgenic mice with chitosan by a parenteral route to avoid the influence of gut microflora. Chitosan induced a maximal intensity on 3 d, and the signal gradually decreased after three days, suggesting that subcutaneous administration of chitosan evoked the PPAR activity, and the induced PPAR activity was decreased to the basal level after 3 days. Administration of chitosan evoked PPAR activations in brain and stomach. These findings suggested that chitosan might affect the biological events in brain and stomach. It has been shown that PPARs play important roles in the pathogenesis of various disorders of
