| Objective: To study medicine release rule of nano-hydroxyapatite / lysinediisocyanate-glycerol polymer / Norvancomycin composites (nHLN) in vivo, observe bacteriostasis effect in vitro and vivo, and observe the effect to prevent the infection in plerosis contaminant and open bone coloboma.Methods: 1. Methods of studying bacteriostasis activity in vitro: According content of Norvancomycin(NVCM),various kinds of nHLN were put in agar culture which were inoculated Staphylococcus aureus/ Bacillus coli/ Bacillus aeruginosus. Inhibition zones were measured each 3d.2. Methods of studying NVCM slow-release:①Local application group: nHLN was implanted in bone coloboma; rabbits were drawn blood at different time and executed to take the bone tissue around nHLN to test NVCM density.②Systemic administration group: nHL was implanted in bone coloboma; rabbits were drawn blood at corresp time and executed to take the bone tissue around nHL to test NVCM density. Characteristic of blood serum NVCM density and bone NVCM density were compared between 2 groups.3. Methods of studying bacteriostasis effect in vivo: rabbits were divided into group A, B, C, D randomly. Analog of bone coloboma was established in the left upper shinbone and infused Staphylococcus aureus. group A was implanted aseptic nHLN in bone cavity. Group B was implanted aseptic nHL ,and injected NVCM after operation. Group C was implanted aseptic nHL ,and not injected any drug after operation. Group D was not implanted anything,and not injected any drug after operation, general state of rabbit ,state of infection and histologic variation were recorded to estimate bacteriostasis effect in vivoResults: 1. Results of studying bacteriostasis activity in vitro: The diameter of inhibition zone to Staphylococcus aureus of group I had been more than 10mm for 78.00±2.56 d, group II for 61.00±1.48 d, group III for 43.50±3.00d, group IV for 35.50±2.15 d , group V for 0.00±0.00 d (PJ<0.01). The diameter of inhibition zone to Bacillus coli of group I had been more than 10mm for 2.42±1.51 d, group II for 1.25±0.87 d. other groups had not seen inhibition zone appearance. Each group had not appeared inhibition zone to Bacillus aeruginosus.2. Results of studying NVCM slow-release: Drug peaks of 2 groups appeared after using drug 1h. The bone NVCM density was 30.25μg/g, the blood serum NVCM density was 2.51μg/ml. The bone NVCM density was 12 times as much as blood NVCM density. It was 23 times after 24 hours . The bone NVCM density was higher than 1μg/g in local application group for 4W, but the blood serum NVCM density was lower than 2.51μg/ml constantly. The blood and bone NVCM density in systemic administration group respectively was 3.64 and 1.82, 2.68 and 2.82, 2.13 and 1.91, 1.32 and 1.02, 0.81 and 0.83 at 0.25, 0.5, 1, 6, 24h. the bone NVCM density in local application group respectively was 8.6, 15.8, 26.0, 22.9 times as much as the bone NVCM density in systemic administration group.3. Results of studying bacteriostasis activity in vivo: Rabbit's temperature, lencocyte count and infection rate in group C and D was higher and weight was lighter than group A and B. Those difference have statistics significance. The tissue slice demonstrated that there was inflammatory reaction in each group. Group A was lightest, had not seen the diapyetic change. Group C and D was most severe. We can saw massive inflammatory cell, multiple sends and tissu necrosis. Fibroplasias was found in each group.Conclusions: 1.nHLN has the good bacteriostasis to Staphylococcus aureus in vitro; the bacteriostasis duration is long. Bacteriostasis activity is positive correlation with dose of NVCM in nHLN.2.The slow-releas duration of nHLN is long. nHLN can maintenance higher NVCM the local bone NVCM density and lowwer blood serum NVCM density than systemic administration. nHLN is a good slow-releas system.3. nHLN can prevent and control efficaciously the infection in contaminant and open bone coloboma. It's a good material which has the function of bone plerosis and anti-infection.
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