组织工程心脏瓣膜裸鼠体内移植的实验研究

目的将人血管混合细胞体外动态种植于脱细胞牛心包构建的组织工程心脏瓣膜（Tissue engineered hean valves，TEHVs）并移植入裸鼠体内，观察其生物学特征变化。方法将体外动态构建的TEHVs移植入裸鼠体内，30d时取材，观察组织、细胞的超微结构变化，种子细胞的生长行为和生物学特征变化，种子细胞与支架材料的黏附性，TEHVs的生物相容性等参数。结果组织学观察见：细胞数量、分层数较移植前增多，并有大量细胞浸润入TEHVs深层组织内：免疫组化显示：TEHVs上细胞的内皮细胞Ⅷ因子、平滑肌细胞α-肌动蛋白、成纤维细胞Fibronectin相关抗原呈阳性表达；扫描电镜见：裸鼠体内移植后细胞数量较移植前增多，细胞表面和细胞之间的网状胶原结构较埋置前增多明显；透射电镜可见：W—P小体、质膜小泡、密斑、密体、微丝等特征性结构。结论TEHVs细胞能够在裸鼠体内定向分化、增殖，生物学特征无改变，TEHVs生物相容性良好。

Experimental Study of Tissue Engineered Heart Valves Implanted in Nude Mice

Objective To evaluate the biological characteristics of tissue engineered heart valves （TEHVs） after implanted into nude mice. Methods The TEHVs were constructed by mixed human vascular cells seeded on de-cellularized bovine pericardium and implanted into nude mice. Ultra-microstructure and the biocompatibility of the TEHVs, the growth behavior of the seeded cells and the ability of their adhesion to acellular bovine pericardium were observed. Results The quantity and the layer of seeded cells in TEHVs increased gradually after being implanted into nude mice, and with time-lapse,the cells penetrated into the deep layer of the pericardium. The seeded cells in the TEHVs verified including endothelial cells （ECs）, smooth muscle cells （SMC） and fibroblast by scanning electron microscopy （SEM）, the quantity of the seeded cells, the floss and fibre on the pericardium grew more than before implantation. The specific granules of the ECs, SMC and fibroblast, such as the Weibel-Palade body and Plasma lemma vesicle, dense patch and dense body, microfilament were observed with transmission electron microscope （TEM）. Conclusion The seeded cells in the TEHVs can differentiate directionally and gen- erate after TEHVs were implanted into nude mice. There were no changes of biological characteristics. The biocompatibility of the TEHVs is satisfactory.