Abstract
Purpose:
Erythrocyte tropomodulin (E-Tmod) is a tropomyosin(TM) binding protein and actin capping protein at the point end of the filaments. It is part of a molecular ruler that plays an important role in generating short actin protofilaments critical for the integrity of cell membrane. Previously we created a knockout mouse model in which lacZ was knocked-in downstream of the E1 promoter to report the expression of full length E-Tmod+/lacZ and E-Tmod-/-. Here we utilize heterozygous (E-Tmod+/lacZ) and homozygous (E-Tmod-/-) mice to study E-Tmod expression patterns in the retina.
Methods:
Tissue Preparation: Eleven heterozygous mice (E-Tmod+/lacZ), three homozygous mice (E-Tmod-/-) and five wide type mice for control group from postnatal day 2 to 12 months were sacrificed. Eyeballs were enucleated, fixed, embedded, frozen, and cut into twelve-um transverse sections with a cryostat X-gal Staining: Sections were incubated in X-gal staining solution (detergent rinse solution supplemented with 5mM potassium ferricyanide, 5mM potassium ferrocyanide, and 1mg/ml X-gal) at 37C for 2-3 hours in the dark.
Results:
1. Eyeball and lens: Two third E-Tmod-/- mice had a complete lens opacities with one eye. And the one eyeball with cataract was smaller than another eyeball, the diameter of one eye was two millimetre, but another eye is three millimetre; 2. The results showed that blue X-gal-positive cells were located in the dendrites of horizontal cells of both E-Tmod+/lacZ mice, especially in the pedicle area. showed a little bit staining were present in the lay of amacrine and ganglion cells with a salt pattern; 3.The result also showed that blue X-gal-positive cells were located in layer of horizontal cells in E-Tmod-/- mice, but morphology of horizontal cells dendrites, especially the pedicle area, was indistinct. Important, photoreceptors layers loss were detected in these E-Tmod-/- mice retina. 4.The retina detachment were observed in all reina section even though retinal architecture were detected.
Conclusions:
The specific E-Tmod expression suggests its role in protecting horizontal cells from mechanical damages in Glaucoma. In addition, X-gal staining result showed that photoreceptors layers did not be detected in the homozygous mice (E-Tmod-/-), which suggests that E-Tmod not only protects HCs from mechanical damage, but also maintain the survival of photoreceptors.
Keywords: 689 retina: distal (photoreceptors, horizontal cells, bipolar cells) •
551 imaging/image analysis: non-clinical •
449 cell survival