Abstract:

BACKGROUND: Amino acid polymer is a kind of new biological engineering materials, it has many advantages and potential application prospect in clinical field. However, the in vivo experiment study of this material is limited.
OBJECTIVE: To evaluate the biocompatibility of a novel biological engineering material, multi-(amino acid) copolymer-calcium sulfate compound, through animal experiments.
METHODS: The multi-(amino acid) copolymer was compounded with calcium sulfate to prepare porous composite material and its diffusion solution. The following tests were performed: Acute general toxicity test: Two groups of SD rats (n=10) received peritoneal injection of diffusion solution and saline, respectively. Change of activity and rat weight within 1 week were documented. Chronic toxicity test: The changes of liver and kidney functions were observed after composite materials were implanted into back muscles of New Zealand rabbits. Intradermal stimulation test: The stimulations such as erythema and edema were observed after the diffusion solution was intradermally injected into the back skin of New Zealand rabbits. Intramuscular implantation test: The composite materials were implanted into musculus sacrospinalis of New Zealand rabbits. The tissue reactions were observed at 1, 2, 4, 8 weeks.
RESULTS AND CONCLUSION: In the acute general toxicity test, the diary activities of rates were normal after the injection of the diffusion solution. Rat body weight was growing similarly in both groups, the increase rate of body weight had no significant difference (P > 0.05). There were no significant damages of rabbits’ liver and kidney functions after implantation of materials into animal muscle. In intradermal stimulation test, skin reactions such as erythema and edema were not observed after the injection of diffusion solution into rabbits. In intramuscular implantation test, the reaction of inflammatory cells of the tissue nearby implants was slight, the fibrous tissue and blood vessels grew into the composite materials, without rejecting reaction. The activity of cytochrome oxidase and lactate dehydrogenase of muscles cells nearby the implants was normal after implantation. The new composite material of multi-(amino acid) copolymer-calcium sulfate has good biocompatibility and excellence safety in vivo, it can degrade and absorb in vivo, thus considered as a good bone repair material.