Doughty MJ. Averaged spacing and 2-d organization of collagen fibrils in the posterior cornea of the rabbit eye assessed by transmission electron microscopy.
Curr Eye Res 2013;
39:329-39. [PMID:
23841461 DOI:
10.3109/02713683.2013.809767]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE
To assess how reproducible collagen fibril spacing might be in the corneal stroma as viewed by transmission electron microscopy by calculating averaged values for the 2-D organization.
METHODS
One cornea from 8 albino rabbits (2 kg) was fixed in situ to preserve natural shape. Thin sections were stained with 2% phosphotungstic acid (PTA) and images taken of fibrils from the central-posterior stroma. After projection at 250,000 X magnification, an overlay was prepared of the fibrils. Using a 500 × 500 nm region of interest (ROI), the distances to all fibril centers were measured to 2 nm resolution.
RESULTS
The sets of fibrils had average diameters between 32.4 and 36.1 nm (group mean ± SD of 34.4 ± 4.2 nm). The mean fibril density was 396 ± 21 per square micrometer, with a fibril area fraction of 38.7 ± 3.9%. The mean distance to the literal nearest neighbor fibril center was 43.2 ± 4.5 nm. A radial distribution analysis showed a distinct nearest neighbors peak at 51 nm. This nearest neighbors peak had an average amplitude of 2.236 ± 0.315, with a broader secondary peak being evident in all data sets centered at 93 nm with an average amplitude of 1.166 ± 0.093 (or 53.3 ± 7.1% of the nearest neighbors peak).
CONCLUSIONS
Overall, these results show that a predictable 2-D organization can be demonstrated for collagen fibrils in rabbit corneas when consideration is given to sample selection and preparation and the image analysis strategy.
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