HAP涂层镍钛记忆合金的组织相容性

HISTOCOMPATIBILITY OF POROUS HYDROXYAPATITE COATING NITI SHAPE MEMORY ALLOY

目的评价HAP涂层镍钛记忆合金的组织相容性,为其在骨缺损修复的临床应用提供理论依据。方法取24只青紫兰兔,体重2.0～2.5kg,随机分为实验组和对照组,每组12只。行左侧股外侧切口,分离显露股骨后,选取股骨下1/3处手术钻孔作为种植区,实验组植入HAP涂层镍钛记忆合金,对照组不植入材料。大腿后外侧肌肉覆盖缺损区。分别于术后7、14、28、56d每组各处死3只动物,取材行大体观察、组织学观察、BMP-2免疫组织化学染色观察及图像灰度值分析,组织学观察结果按照中华人民共和国国家标准GB/T16886.6-1997从炎症、纤维组织囊壁形成、材料降解及周边组织反应4个方面进行组织学评价。结果所有兔均存活至取材,两组植入物完全包埋于骨组织内部,无松动,无明显骨吸收现象。材料植入后7d,两组炎性细胞浸润和纤维增生最明显,纤维组织囊壁形成,植入材料呈大片状被囊壁包裹;术后56d,实验组部分标本囊壁结缔组织增生反应仍较明显,劣于对照组,但分级符合GB/T16886.6-1997体内植入标准。免疫组织化学染色示内源性BMP-2定位于多能MSCs、成骨细胞的胞质内;两组图像分析结果显示,BMP-2随骨缺损的修复过程呈阶段性分泌,两组BMP-2在术后14d时表达最高,以后逐渐降低。BMP-2在各时间点染色灰度值比较差异均无统计学意义(P>0.05)。结论HAP涂层镍钛记忆合金作为生物医学材料具有良好的骨组织相容性。

Objective To evaluate the histocompatibil ity of porous hydroxyapatite （HAP） coating NiTi shape memory alloy and to provide a theoretical basis for its cl inical appl ication in bone defect repair. Methods Twenty-four Chinchilla rabbits weighing 2.0-2.5 kg were randomized into experimental group and control group （n=12）. HAP coating NiTi shape memory alloy was implanted into the distal part of left femur of 12 rabbits in the experimental group, while holes without alloy implantation were performed on the control group. At 7, 14, 28 and 56 days after implantation, the animals were killed （3 rabbits in each group at a time）. Gross observation, histology observation, BMP-2 immunohistochemistry observation and image grey scale analysis were performed. And the histology observation was evaluated by GB/T16886.6-1997 in terms of inflammation, capsule wall of fibrous tissue, materials degradation and the response of peripheral tissue. Results All of the animals survived until being killed. The implants reached a peak embedded in bone tissue wholly, without loosening and bone absorption. The inflammatory cell infiltration and fibrous hyperplasia were at 7 days after implantation, with the formation of cyst wall of fibrous tissue and the implant wrapped by the cyst wall. The response of connective tissue proliferation was still obvious in partial samples of experimental group at 56 days after implantation, which was wrose than the control group but consistent with the in vivo implantation standard of GB/T16886.6-1997. Immunohistochemistry observation displayed the endogenous BMP-2 were in the cytoplasm of MSCs and osteoblast. The result of image analysis showed the expression of BMP-2 were staged in line with the repair of bone defect, two groups witnessed the peak expression of the BMP-2 at 14 days after implantation. There were no significant differences among different time points in the staining gray scale of BMP-2 （P 〉 0.05）. Conclusion HAP coating NiTi shape memory alloy, as a biomedical material, has excellent histocompatibility with bone.