Abstract: OBJECTIVE: To investigate sensitivities of two methods and four time points for detecting muscle implantation. Consequently,the rabbit tissue response grading method and semi quantitative score evaluation method were used to detect tissue stimulation responses to seven kinds of medical materials after short-term and long-term muscle implantation. METHODS: The left and right sides of 84 New Zealand white rabbits were compared in this investigation. The same test and control samples were implanted into the left and right paraspinal muscles at 4 implantation points with an interval of 2.5 cm. On the 15th,30th,60th and 90th day after implantation,3 rabbits were killed respectively,and the 1.0-1.5 cm³ of back muscle tissues which contained the implanted samples were removed. The numbers of inflammatory cells were counted microscopically. Proliferative reaction indexes were graded and semi quantitative scorings were performed according to the GB/T 16886 standard. The gradings or stimulation degrees were determined according to the difference between the total average scores from the left and right sides. RESULTS: The samples which showed mild irritation by tissue response grading method were No.3,No.5 (60 days after implantation) and No.3 (90 days after implantation). The samples which showed mild irritation by the semi quantitative score evaluation method were No.5 (30 days after implantation),No.3,No.4,No.6 (60 days after implantation),No.3 and No.5 (90 days after implantation). The sensitivity of the two methods and time points to observe inflammatory reactions and tissue reactions were different. CONCLUSION: The semi-quantitative score evaluation method was better than the tissue reaction grading method. In addition,multiple implantation time points were better than one time point and the detection sensitivities for sample implantation were better after 60 d.

Key words: rabbit, muscle implantation, medical raw materials, semi quantitative score, tissue response grading, irritation