肩峰下激素局部注射治疗大鼠肩袖损伤

Type Ⅲ Collagen and histological change in treatment for rat rotator cuff injury with subacromial corticosteroid injection

目的通过测定Ⅲ型胶原的动态变化观察肩峰下激素局部注射对大鼠肩袖损伤修复的影响。方法将36只SD大鼠随机分成4组：正常肩袖组6例（A组）；肩袖损伤组6例（B组）；正常肩袖＋皮质激素治疗组12例（C组）；肩袖损伤＋皮质激素治疗组12例（D组）。B、D组使用大鼠双侧冈下肌腱滑膜面建模，切开冈下肌腱全厚层的50％，宽约5mm。C，D组肩峰下滑囊注身寸0．05ml皮质激素（得保松）。分别于3、6周取冈下肌腱标本进行苏木素．伊红（HE）染色、Masson染色检查以及免疫组织化学染色测定Ⅲ型胶原的表达。结果组织形态学：激素治疗肩袖损伤后3周可见胶原纤维排列紊乱，胶原索断裂和坏死；6周后略好转。Ⅲ型胶原：（1）肩袖损伤后Ⅲ型胶原表达升高（P〈0．05）；（2）激素在治疗肩袖损伤后3周Ⅲ型胶原明显较正常组和肩袖损伤组高（P〈0．01）；（3）激素治疗肩袖损伤后6周，Ⅲ型胶原表达仍高；（4）正常肩袖激素治疗后3周Ⅲ型胶原表达明显增高，但在6周后恢复到正常水平（P〉0．05）。结论激素在治疗肩袖损伤时能通过刺激Ⅲ型胶原的表达促进肩袖修复，但肌腱的组织学结构和强度发生显著变化。即使正常的肩袖组织，在激素局部注射后也会产生暂时性的肩袖损伤修复反应。

Objective To study the effect of corticosteroid on rat rotator cuff injury healing by observing histological change and quantifying the dynamic change of type Ⅲ collagen. Methods Thirty-six Sprague-Dawley rats were randomly divided into 4 groups ：6 rats group A （normal rotator cuff） ,6 rats in group B （rotator cuff injury） ,12 rats in group C （normal rotator cuff treated with cortieosteroid） ,and 12 rats in group D （rotator cuff injury treated with eorticosteroid）. In the rats of groups B and D, a partial-thickness rotator cuff injury was created by cutting 50% of thickness and 5 mm of width of the bilateral in- fraspinatus tendon 5 mm from its humeral insertion. 0.05 ml corticosteroid （Diprospan） was injected into the subacromial space of the rats in groups C and D. Total iufraspinatus tendons were harvested for HE, Masson staining,immunohistochemical staining and type Ⅲ collagen quantification. Results Histological change ： In corticosteroid treatment groups, the normal arrangement of the collagen bundles was replaced by the disorganized collagen bundles with fragmentation of the collagen bundles and collagen necrosis at 3rd week, and the arrangement was improved very slightly at 6th week. Type Ⅲ collagen ： （ 1 ） The type Ⅲ collagen levels were significantly increased after the rotator cuff injury （ P 〈 0.05 ） ; （ 2 ） At 3rd week, the type Ⅲ collagen levels in corticosteroid treatment groups were significantly higher than in normal rotator cuff group and rotator cuff injury group （ P 〈 0.01 ） ; （ 3 ） At 6th week, the type Ⅲ collagen levels in rotator cuff injury treated with corticosteroid group remained on a very high level; （4） The type Ⅲ collagen levels in normal rotator cuff treated with corticosternid group were significantly increased at 3rd week, and returned to the normal at 6th week （ P 〉 0.05 ）. Conclusion Corticosteroid can induce type Ⅲ collagen synthesis during rotator cuff healing, but even a single dose of corticosteriod can cause negative effect on the histological structure of the rotator cuff.