不同程度单纯性先天性上睑下垂患者提上睑肌的病理研究

Pathological study of the levator palpebrae superioris muscle in patients with different severities of simple congenital ptosis

目的观察不同程度单纯性先天性上睑下垂(SCP)患者的提上睑肌病理变化。方法收集2018年8月至2019年10月在武汉爱尔眼科医院汉口医院行提上睑肌缩短术的SCP患者68例102眼的提上睑肌标本作为观察组,按上睑下垂的严重程度分为遮盖范围≤4 mm组35眼、遮盖范围>4 mm~≤6 mm组30眼和遮盖范围>6 mm组37眼,同时选取由武汉红十字会爱尔眼库提供的8名正常供体的新鲜提上睑肌组织作为对照组。分别对提上睑肌标本进行Masson三色染色和α-平滑肌肌动蛋白(α-SMA)免疫组织化学染色,并使用ImageJ软件测量标本的胶原纤维面积比、骨骼肌纤维面积比及α-SMA的积分吸光度(IA)值。选取17个标本(对照组标本2个,遮盖范围≤4 mm组、遮盖范围>4 mm~≤6 mm组和遮盖范围>6 mm组各5个)行透射电子显微镜观察。结果光学显微镜下可见,与对照组相比,观察组标本中骨骼肌纤维数量减少,肌纤维走行紊乱,部分肌横纹消失,细胞间质中纤维结缔组织增生。遮盖范围≤4 mm组、遮盖范围>4 mm~≤6 mm组、遮盖范围>6 mm组胶原纤维面积比明显高于对照组,骨骼肌纤维面积比明显低于对照组,差异均有统计学意义(均P<0.0083)。观察组标本含有较多的平滑肌纤维,肌纤维中可见α-SMA呈阳性表达。遮盖范围≤4 mm组、遮盖范围>4 mm~≤6 mm组、遮盖范围>6 mm组标本中α-SMA的IA值分别为7195.28(5935.69,14058.29)、55584.18(33861.88,80419.32)和166507.76(119121.95,187890.86),高于对照组的5543.03(4867.67,8312.02),其中遮盖范围>4 mm~≤6 mm组和遮盖范围>6 mm组与对照组比较差异均有统计学意义(均P<0.0083)。透射电子显微镜下观察结果显示,观察组标本中的平滑肌细胞质内含有丰富的细胞器,部分线粒体损伤,未见密丝及密体等平滑肌细胞的特征性结构。结论SCP患者的提上睑肌中存在异常的平滑肌细胞,提上睑肌的发育不良可能与这类异常的肌细胞有关。

Objective To observe the pathological changes of levator palpebrae superiors muscle in patients with different severities of simple congenital ptosis(SCP).Methods Levator palpebrae superiors muscle specimens from 102 eyes of 68 patients with SCP who received levator palpebrae superiors muscle shortening surgery at Wuhan Aier Hankou Eye Hospital from August 2018 to October 2019 were collected as the observation group.According to the severity of ptosis,the specimens were divided into three groups,coverage≤4 mm group(n=35),coverage>4 mm to≤6 mm group(n=30),and coverage>6 mm group(n=37).Fresh levator palpebrae superiors muscle tissues from 8 normal donors in Aier Eye Bank of Wuhan Red Cross were selected as the control group.All specimens were performed with Masson trichrome staining and immunohistochemical staining forα-smooth muscle actin(α-SMA),and ImageJ software was used to measure the collagen fiber area ratio,skeletal muscle fiber area ratio and the integrated absorbance(IA)value ofα-SMA.Seventeen specimens(2 from the control group,5 from coverage≤4 mm group/coverage>4 mm to≤6 mm group/coverage>6 mm group)were observed with a transmission electron microscope(TEM).This study protocol adhered to the Declaration of Helsinki and was approved by an Ethics Committee of Wuhan Aier Hankou Eye Hospital(No.HKAIER2018IRB-005-01).All patients and their legal guardians were well informed about the treatment method and the purpose of sampling and voluntarily signed informed consent.Results Compared with the control group,the skeletal muscle fiber was reduced in number and was in disordered arrangement,and the striation of some muscle fibers disappeared,and hyperplastic fibrous connective tissue was found in intercellular substances in the observation group.The collagen fiber area ratio of the coverage≤4 mm group,coverage>4 mm to≤6 mm group,coverage>6 mm group were significantly higher than that of the control group,and the skeletal muscle fiber area ratio of the three groups was significantly lower than that of the control group(all at P<0.0083).There were more smooth muscle fibers and positive expression ofα-SMA found in the specimens of the observation group.The IA value ofα-SMA of the coverage≤4 mm group,coverage>4 mm to≤6 mm group,coverage>6 mm group was 7195.28(5935.69,14058.29),55584.18(33861.88,80419.32),166507.76(119121.95,187890.86),respectively,which were all higher than 5543.03(4867.67,8312.02)of the control group,among which,there were statistically significant differences between the control group and the coverage>4 mm to≤6 mm group,coverage>6 mm group(both at P<0.0083).Abundant organelles and some damaged mitochondria were found in smooth muscle cytoplasm in the observation group with a TEM.But no characteristic structure of smooth muscle cells such as dense patch and dense body was detected.Conclusions There are abnormal smooth muscle cells in the levator palpebrae superiors muscle of SCP patients,and the dysgenesis of the levator palpebrae superiors muscle may be related to this abnormal muscle cell.