The Levator Muscle And Aging

Ptosis is a disease that can occur at all ages which affect the appearance and can cause function lose in daily life.It is mainly divided into congenital ptosis and acquired ptosis.involutionnal blepharoptosis is the most common form in adults with acquired ptosis.At present,the mainstream view of the academic community believes that the pathogenesis of involutionnal blepharoptosis is levator aponeurosis disinsertion or degeneration,and the function of the levator palpebrae superioris muscle(LPS)remains normal.Correspondingly,research on the relationship between skeletal muscle and aging also found that extraocular muscles(EOMs)as a special muscle group generally have higher regenerative capacity than ordinary skeletal muscles,and there is a hypothesis that EOMs may not be affected by aging.However,most of these studies are carried out on animal models and the three pairs of EOMs that coordinate eye movements except LPS.The research on the LPS and aging is still very rare.As some recent studies have found that fat infiltration in the LPS of involutionnal blepharoptosis patients,there are more and more people doubt about the mainstream view.Whether the LPS can be protected from aging,and whether the LPS itself is really normal in elderly patients with involutionnal blepharoptosis has also become a concern of researchers in related fields.In order to verify the relationship between LPS and aging,this study selected 20 LPS samples(excluding the levator aponeurosis part)from.11 dead bodies without related eye diseases from the Life Donation Center of the Peking Union Medical College:Of the 11 dead bodies,6 were males,5 were females,8 specimens were from females,and 12 were from males,9 from the left eye and 11 from the right eye.The samples were divided into younger groups(age 65-79 years,5 dead bodies,average age 73.6±5.6 years,10 specimens)and older groups(age 82-100 years,6 dead bodies,average age 88.5±6.5 years old,10 specimens),HE staining,Masson staining and VG staining were performed on each specimen,and the distribution and integrity of muscle fibers,fat infiltration,connective tissue hyperplasia,e tc.were observed under light microscope.For HE staining of each specimen,randomly select three high magnification fields,the ratio of muscle fiber area was calculated with IPP software,and take the average as the ratio of muscle fiber area of the specimen;the ratio collagen fiber area of Masson staining of each specimen was calculated in the same way.According to the characteristics of the data itself,the Mann-WhitneyU test or t test was used to analyze the effects of age,gender,left/right eyes on the ratio of muscle fiber area and collagen fiber area.Different degrees of fat infiltration were observed in specimens of 20%younger group and 20%older group.Localized collagen fiber hyperplasia was observed(3 specimens in the younger group,two of which were from the same dead body;1 specimen in the older group).Grouped by age,there is no statistically significant difference between the ratio of muscle fiber area and collagen fiber area between younger and older groups(P muscle=0.112 P glue=0.226);grouped by gender,the ratio of muscle fiber area and The collagen fiber area ratio difference is also not significant(P muscle=0.452 P glue=0.537);according to the grouping from the left and right eyes,there is no significant difference between the muscle fiber area ratio and collagen fiber area ratio(P muscle=0.732 P glue=0.382)According to the results of this study:in older adults,some people have fat infiltration of the LPS;there is no significant difference between the ratio of the area of the levator muscle fiber and the area of collagen fiber between different age groups.At the same time,neither the sex nor the source of the specimen(left or right eye)will have a significant effect on the ratio of muscle fiber area and collagen fiber area.