Abstract:

Objective　To analyze the reactivity of chitosan/ SiO2 (CS-SiO2) and chitosan/SiO2/hydroxyapatite (CS-SiO2-HA) hybrid materials in vivo. 　Methods　CS-SiO2 or CS-SiO2-HA hybrid materials were implanted respectively into the gastrocnemius muscle of C57BL/6 mice and the control group was set up (gastrocnemius blunt dissection after direct suture). Frozen sections of materials containing the gastrocnemius were removed 14, 28, 42, 56 d after implantation, followed HE staining and immunofluorescence to observe local inflammation, muscle fibrous necrosis and regeneration induced by the implanted materials. 　Results　Histological observation showed that in the early stage of intramuscular implantation (14d), CS-SiO2 and CS-SiO2-HA hybrids both induced inflammatory cell infiltration, and the latter was more significant. Number of infiltrated cells began to decrease after 28 d and intramuscular inflammation in the group of CS-SiO2 almost disappeared while there was a small amount of infiltration in CS-SiO2-HA at 56 d. Immunofluorescence further confirmed that CS-SiO2-HA hybrids led to more severe necrosis of muscle fibers, triggered more extensive and prolonged inflammatory infiltration of mononuclear macrophages compared to CS-SiO2. Intramuscular inflammation basically disappeared and the repair of muscle fibers was completed two months after transplantation of CS-SiO2 and CS-SiO2-HA hybrids. Conclusions　CS-SiO2-HA and CS-SiO2 hybrid materials can both induce a short-term and local inflammatory reactions while CS-SiO2 has a better compatibility in vivo than that of CS-SiO2-HA hybrids.

Key words: Chitosan, 　SiO2, 　Hydroxyapatite, 　Inflammation, 　Hybrids