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Microfilaments in preretinal membrane cells of proliferative vitreoretinopathy
Abstract:
Electron microscopy was carried out on 8 preretinal membranes surgically obtained from 8 patients after vitrectomy and on primary culture cell outgrowths from 6 preretinal membranes from 6 patients, with particular attention to the presence of actin. Actin was detected as microfilaments in the cultured cells and in the preretinal membrane cells as well, as confirmed by the arrowhead formation seen after heavy meromyosin treatment. The cultured cells and preretinal membranes were glycerinated, and exposed to ATP and Mg2+. With the ATP treatment the cultured cells were observed to contract, and intracellular microfilaments aggregated and formed contraction bands, which are known to be the product of interaction between actin and myosin. Parts of the preretinal membranes were also observed to contract after treatment; in the cells of the preretinal membranes the contraction bands were observed. It was concluded that the intracellular microfilaments in the cells of the preretinal membranes contain actin capable of contraction, thereby inducing contraction of the membrane which exerts traction on the retina.
Insights
Preretinal membranes contain actin and myosin, which interact to cause cellular contraction. This contraction contributes to the traction exerted on the retina, a key factor in retinal detachment.
Area of Science:
- Ophthalmology
- Cell Biology
- Biochemistry
Background:
- Preretinal membranes are associated with retinal traction and detachment.
- The cellular and molecular mechanisms underlying preretinal membrane contraction are not fully understood.
Purpose of the Study:
- To investigate the presence and function of actin within preretinal membranes.
- To determine if actin in preretinal membranes is capable of mediating cellular contraction.
Main Methods:
- Electron microscopy was used to examine surgically obtained preretinal membranes and cultured cells.
- Heavy meromyosin treatment was employed to identify actin.
- ATP and Mg2+ treatment was used to assess contractile properties.
Main Results:
- Actin was identified as microfilaments within both cultured preretinal cells and cells of the membranes.
- ATP treatment induced contraction in cultured cells and parts of the preretinal membranes.
- Contraction bands, indicative of actin-myosin interaction, were observed.
Conclusions:
- Intracellular microfilaments in preretinal membranes contain functional actin.
- This actin is capable of contraction, leading to membrane contraction and retinal traction.