Objective:To study the promoting function of recombinant human bone morphogenetic protein-14 (rhBMP-14) in the healing of tendon-bone of rabbit rotator cuff injury after reattachment. Methods: Forty-five adult male New Zealand white rabbits aged 8 months, randomly selected three as normal group for biomechanical testing. The other forty-two rabbits were randomized into three groups(fourteen animals/group). Underwent bilateral detachment and repair of the supraspinatus tendon in the experiment. The animals received one of three treatments at the tendon-bone interface. The experimental group received a mixture of rhBMP-14 and chitosan thermosensitive hydrogel(CS/GP). The CS/GP control group received only CS/GP. The blank control group were not handled. Seven animals in each group were sacrificed at 4 and 8 week. At each time point, four specimens were observed by H.E. stain. Collagens were observed by Picrate Sirius Red staining on four specimens. Measured the areas of type Ⅰ and type Ⅲ collagens and calculated their ratio. Six specimens were allocated for biomechanical testing. Results:(1)At 4-week, histological analysis of the tendon-bone interface showed an increasing collagen fibrils and cartilage tissue formed in the tendon-bone interface in the rhBMP-14 group, and it had more cartilage cells, the collagenous matrix was oriented in line. In the CS/GP control group and blank group, there were little collagen fibrils and cartilage tissue formed in the tendon-bone interface. At 8-week, the interface tissue in the rhBMP-14 group was denser and the collagenous matrix was more oriented in line with the tendon. Sharpey ’s fibers were found in the interface at the 8-week of the rhBMP-14 group. In the CS/GP control grouprh and blank control group, there was little appearing fibrocartilage zone. Picrate Sirius red staining showed that the ratio of type Ⅰcollagens and type Ⅲcollagens raised with the increase of time for each group, and the difference was statistically significant(P<0.01). The ratio of the rhBMP-14 group increased significantly than the control group at the same period of time, the difference was statistically significant(P<0.01). The ratio of the CS/GP control group and blank control group in the two periods had no significant difference. (2)Biomechanical analysis displayed that the maximum load values and stiffness of bone-tendon interface increased over time in all groups, which of the rhBMP-14 group was significantly higher than those in two other groups(P<0.01).Conclusions: rhBMP-14 can promote the mature of ten-don insertion, induce direct insertion formation and increase the maximum load values and stiffness of the tendon-bone inter-face after surgery. It plays an important role in repair of rotator cuff tears.%目的：研究重组人骨形态发生蛋白-14(recombinant human bone morphogenetic protein-14, rhBMP-14)在兔急性肩袖损伤后肌腱止点重建过程中的作用。方法：共取45只8月龄雄性新西兰大白兔，随机选取3只作为正常组，进行生物力学测试。其余42只随机分成3组，每组14只。采取双侧冈上肌腱完全离断模型作为肩袖急性损伤模型，并一期行肌腱止点重建术。实验组在腱-骨界面注射以壳聚糖温敏水凝胶(chitosan/glycerophosphate, CS/GP)为载体的rhBMP-14；实验对照组仅填充CS/GP；空白对照组不给予任何处理。分别于处理后第4周和第8周随机处死实验用兔7只，切取肩袖标本。随机选取各组4例肩袖标本进行HE染色观察腱-骨愈合情况，取各组4例标本进行苦味酸天狼星红染色进行Ⅰ型胶原和Ⅲ型胶原面积测定并进行比较。另取各组6例标本进行生物力学测试。结果：(1)组织学观察：HE染色显示术后4周实验组有大量软骨细胞增生，并伴有胶原纤维和软骨组织形成，胶原方向较为恒定；在实验对照组及空白对照组仅有少量胶原纤维及软骨形成，方向性差。实验组腱-骨界面组织于术后8周连接紧密，胶原纤维方向一致，并伴有矿化胶原纤维形成，腱-骨界面出现明显的Sharpey’s纤维连接，有类似直接止点形成；实验对照组和空白对照组有部分似直接止点的矿化胶原纤维形成，大部分由结缔组织充填。苦味酸天狼星红染色显示随着时间的增加，实验对照组及空白对照组Ⅰ型胶原面积和Ⅲ型胶原面积之比均有所提高，而实验组的面积比例在选取的相同时间段较对照组明显提高(P<0.01)。(2)生物力学测试显示：术后3组最大载荷及刚度都随时间的延长而增强。实验组在第4周、第8周的最大载荷与刚度都较实验对照组与空白对照组明显增高(P<0.01)。结论：rhBMP-14可促进肌腱止点的成熟，并可诱导直接止点形成，明显提高腱-骨界面的最大载荷及刚度，在修复肩袖损伤的过程中具有重大意义。
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