曲安奈德肌内注射诱导兔咬肌萎缩的实验研究

Rabbit masseteric muscle atrophy resulting from triamcinolone for injection

目的:探讨肌内注射曲安奈德诱导咬肌萎缩的效果及其组织改变。方法:30只新西兰白兔随机分为正常对照组和5个观察时间的曲安奈德组(分别进行2,4,8,12和24周观察),每组5只。每只实验兔一侧咬肌内注射曲安奈德1 mg·kg-1,另一侧注射生理氯化钠溶液作自身对照。用B超测松驰状态下咬肌最大厚度,完整切除双侧咬肌称咬肌湿重,并留取部份肌组织做切片进行HE染色、ATP酶染色和NADH-TR(烟酰胺腺嘌呤二核苷四唑还原酶)染色,光镜下观察并进行图象分析。结果:与自身对照侧和正常对照组咬肌比较,曲安奈德给药侧咬肌湿重和厚度均明显减小,第8周咬肌湿重和厚度降至最低,并维持至24周末;HE染色观察曲安奈德给药侧咬肌横切面肌细胞直径减小;TP酶和NADH-TR染色见曲安奈德给药侧Ⅱ型肌纤维减小,Ⅱb型纤维更加明显,Ⅰ型纤维无明显变化。自身对照和正常对照组咬肌之间无显著性差异。结论:曲安奈德可诱导Ⅱ型肌纤维萎缩,对Ⅰ型肌纤维无明显影响。

Objectives： To investigate morphologic and histopathological changes of rabbits＇ masseteric muscle atrophy resulted from triamcinolone for injection. Methods：30 New Zealand rabbits were randomly 1：1 assigned to one of 6 groups. Group 1 was used as normal control, and the rest of 5 groups were injected with triamcinolone 1 mg·kg^-1 at one side of masseter and with normal saline at anther side of masseter. The rabbits were sacrificed under anesthesia to collect both masseters after they were injected for 2, 4, 8, 12 and 24 weeks, respectively. The thickness of the masseter was measured by B ultrasonic technique and the masseters were weighed and then dyed with HE staining, ATP enzyme staining and NADH-TR staining, respectively. The imaging analyses were conducted by the morphologic, histopathological and histochemical examinations using optical microscopy. Results：Compared with the masseters in the normal control and at normal saline side, the triamcinolone-treated side of the masseter showed lower weights and less thickness. The reduction of the massetric wet weights and the most atrophy of the masseters aggravated maximally in the 8^th week post the injection and remained the maximal worsening until the end of the 24 weeks. The HE staining found that the cellular diameters of the transected masseteric muscles were significantly reduced, and the ATP enzyme staining and NADH-TR staining showed that type Ⅱ fibers were shrunk, especially the Ⅱb fibers. No significantly shrink was found in type Ⅰ fibers. Conclusion：Triamcinolone makes the muscle atrophy of type Ⅱ muscular fibers and no significant impact on type Ⅰ muscular fibers.