下肢伸直襁褓体位对髋臼软骨复合体发育影响的实验研究

Developmental changes of acetabular cartilage complex: an experimental study of a straight-leg swaddle model of newborn rats

摘要:

目的：本实验通过建立下肢伸直襁褓体位的大鼠动物模型及对实验动物进行大体标本及病理研究观察，探讨下肢伸直襁褓体位对髋臼软骨复合体大体形态及其不同骺板区域软骨细胞成熟的影响。方法：实验组：将31只新生Wistar幼鼠用医用胶带将双小腿、双髋关节缠绕固定10 d，保持髋关节伸直内收位，模拟双下肢伸直襁褓体位。对照组：另31只新生幼鼠双下肢不予处置。母鼠喂养，笼中自由活动。10 d后处死，通过大体标本、组织学、VEGF和Ⅹ型胶原免疫组化染色观察髋臼变化。结果：下肢伸直襁褓体位动物模型制作成功。大体观察：实验组髋臼变小变浅，内部软组织增生，49髋发生髋关节脱位（49/54)，部分出现假臼；对照组髋臼轮廓正常，无假臼出现，2髋脱位（2/60)，对照组脱位率与实验组差异有非常显著性(P<0.01)。番红O-快绿染色见实验组橙红色软骨区域较对照组宽。实验组髋臼软骨复合体的髂骨、坐骨、耻骨各支肥大层VEGF和Ⅹ型胶原表达较对照组低；实验组髋臼关节软骨髂骨支肥大层VEGF与X型胶原阳性表达较坐骨支、耻骨支低。结论：下肢伸直襁褓体位大鼠髋臼软骨复合体骺板肥大层软骨细胞VEGF、Ⅹ型胶原的表达水平降低，显示该体位可能导致髋臼软骨复合体软骨细胞成熟障碍，干扰髋臼正常发育乃至脱位。［中国当代儿科杂志，2009，11（10）：836-840］

Abstract:

OBJECTIVE: By establishing a model of straight-leg swaddle of newborn rats and observing the experimental animals′ hips morphologically and pathologically, this study explored the changes of gross appearance of the acetabulum and the maturity of cartilage cells in the different regions of acetabular cartilage complex. METHODS: The legs and hips were fixed by adhesive tape for 10 days in the position of hip extension and adduction in 31 newborn Wistar rats (experimental group). The other 31 newborn rats without legs and hips treatment were used as the control group. After 10 days raising in the same condition, all the rats were sacrificed. The gross appearance, histological observations and VEGF and type X collagen immunohistochemistry were used for examining the acetabulum changes. RESULTS: A straight-leg swaddle model of newborn rats was established successfully. In the experimental group the acetabulum became shallow and small and surrounded by more soft tissues. There were 49 dislocated hips (49/54) in the experimental group and 2 hips dislocated (2/60) in the control group (P<0.01). Fake acetabulum appeared in the experimental group. In the control group, the shape of the acetabulum was normol, and no fake acetabulum was found. The safranin O-fast green staining showed that the orange-red cartilage in the experimental group was wider than the control group. Immunohistochemistry observations showed VEGF and type X collagen immunoreactivities in the hypertrophic layer of the acetabular cartilage complex in the experimental group were lower than those in the control group. The percentages of VEGF positive and type X collagen positive cells in the iliac hypertrophic layer of the acetabular articular cartilage were significantly higher than those in the ischiadic ramus and the pubic branch in the experimental group. CONCLUSIONS: VEGF and type X collagen immunoreactivities in acetabular cartilage cells decrease in a straight-leg swaddle model of newborn rats. This suggests that this position might lead to dysmaturity of the acetabular cartilage cells and affect the development of the acetabulum.［Chin J Contemp Pediatr, 2009, 11 (10):836-840］