Purchase this article with an account.
M. Goralska, M.C. McGahan; Properties of Ferritin in the Lens Fiber Mass of Different Age Dogs . Invest. Ophthalmol. Vis. Sci. 2006;47(13):2534.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To determine if ferritin concentration, subunit composition and ability to store iron changes after differentiation of lens epithelial cells into fiber cells and during the process of aging. Ferritin consists of 24 subunits of two types heavy (H) and light (L). The H/L ratio is tissue specific and if modified alters ferritin Fe storing capacity.
Canine lenses from dogs age 3 months to over 8 year were dissected, fibers tissue was sonicated in 10mM Tris/HCl buffer pH 7.4 containing 2% SDS and heated for 15 min at 75° C. Ferritin chains were analyzed by Wetern Blotting using anti–H and anti–L ferritin chain antibodies. Ferritin content of homogenates was determined by ELISA using goat anti–horse ferritin antibodies. Incorporation of iron into ferritin was measured after incubation of homogenates with 59FeCl followed by separation of labeled ferritin on 8% SDS–PAGE and quantitation of 59Fe–ferritin by an imager.
Ferritin concentration in fiber mass decreased with age of canine lenses (over 10 fold difference from 3 month to 8 year old dogs). Both, H– and L–ferritin chains present in fiber mass had migrating pattern different from the chain specific standards. Weight of H–chain was ∼ 12 kD instead of 21 kD and L–chain 30 kD instead of 19 kD. The analysis of iron incorporation into ferritin revealed the presence of assembled ferritin of proper size containing radioactive iron. Ferritin in fibers from younger lenses incorporated about four times more iron than ferritin from lenses of 8 year old dogs.
Fiber mass contained assembled ferritin capable of storing iron. Its concentration and amount of stored iron declined with age. Ferritin H– and L–chains in fiber mass differed from ferritin chains found in lens epithelial cells and most likely were modified post–translationally. It is to be determined if the assembled ferritin in lens fibers consist of either proper subunits, or modified subunits, which may accumulate and form the separate, non–functional pool of ferritin.
This PDF is available to Subscribers Only