Degradation of silk fibroin/polylactic acid composites at different proportions in mice / 中国组织工程研究

ABSTRACT

BACKGROUND: In our previous study, we prepared some silk fibroin/polyactic acid composite materials at different proportions, which are verified as tissue-engineered materials with good performance by systemic hypersensitivity test, acute toxicity test, hemolysis test, pyrogenic test, and cell co-culture experiment. OBJECTIVE: To study the subcutaneous degradation of silk fibroin/polylactic acid composite materials at different proportions in mice. METHODS: Fifty-four ICR mice were subjected to subcutaneous cystic clearance on the both sides of the spine, and then randomized into three groups. The silk fibroin/polylactic acid composites at 4060, 5050, and 3070 were implanted into the cystic space, respectively. The specimens were taken out at 1, 3, 9 weeks after implantation. Histopathological staining, Masson staining, and CD34 immunohistochemical staining were performed. RESULTS AND CONCLUSION: (1) Hematoxylin-eosin staining At 9 weeks after implantation, new blood vessels gradually formed and visible fibroblasts gradually grew into the composites in the three groups. Structural collapse of the materials became more apparent, and tissues and cells further grew into the materials. The 4060 and 5050 composites were degraded more quickly than the other one. (3) Masson staining At 9 weeks after implantation, mature blood vessels and collagen fibers were detectable in the three groups, which were more apparent in the 4060 and 5050 groups than the 3070 group. The collagen fiber expression in the 5050 group was significantly higher than that in the other two groups at different time after implantation (P < 0.05). (3) CD34 immunohistochemical staining At 1-3 weeks after implantation, CD34 positive expression gradually increased in the three groups. After 9 weeks, the CD34 expression decreased in the three groups; however, the CD34 positive expression in the 5050 group was significantly higher than that in the other two groups at different time after implantation (P < 0.05). To conclude, the silk fibroin/polylactic acid composite material at a proportion of 5050 was degraded more quickly in mice.