Histopathological change of levator aponeurosis in patients with congenital blepharoptosis

Abstract

Background Congenital blepharoptosis is a common disorder of eyelid movement.Overseas research showed that the most likely mechanism of congenital blepharoptosis is the hypoplasia of levator.But the study on Chinese is still lack.Objective This study was to investigate the pathological features of hypoplasia in levator aponeurosis in Chinese congenital blepharoptosis patients.Methods Twenty-one patients with congenital blepharoptosis were divided into mild group (3 cases),moderate group (14 cases) and severe group (4 cases).Samples of the levator aponeurosis were obtained during the levator palpebrae superioris muscle shortening surgery.Hematoxylin-eosin,special staining and immunohistochemistry were performed to analyze the characteristics of the samples.Normal samples of fresh levator aponeurosis were obtained from the donors in the eye bank of Beijign Tongren Hospital.Results Hematoxylin-eosin staining and special staining showed that with the increase of severity,the cases of levator fibers sparse,fibrous tissue hyperplasia and endomysium defect were gradually increased,showing significant differences among the different groups (Z =-0.702,P =0.002 ; Z =0.738,P ＜ 0.001 ; Z =0.746,P ＜ 0.001).Four samples (19％) presented with adipose in the interstitial tissue.Immunohistochemistry showed that the expression of muscle proteins myosin was weaker in the levator aponeurosis of patients with congenital blepharoptosis than that in the normal samples,and the expression intensity of collagen type Ⅲ in the samples enhanced in comparison with the normal samples.However,there were no significant differences in the expression of actin,myoglobin,fibronection,collagen type Ⅵ and laminin among various groups (all at P＞0.05).Conclusions The levator aponeurosis appears developing abnormality in Chinese patients with congenital blepharoptosis.The histopathological change degree is parallel with the severity of congenital blepharoptosis. Key words: Blepharoptosis/congenital; Levator aponeurosis; Histopathology; Development