Abstract
Purpose: :
Uncovering the chemical and physiological changes that occur during corneal embryogenesis will lead to a heightened understanding of the tightly controlled developmental events that ultimately determine the requirements for stromal light transmission and corneal transparency. The current study aims to develop techniques for the analysis of bulk tissue, and to explore physico-chemical variations in corneal embryogenesis.
Methods: :
A combination of synchrotron scanning X-ray fluorescence microscopy and X-ray absorption near-edge structure spectroscopy were utilized for the investigation of, respectively, the chemical composition and sulfur speciation in the developing chick corneas at embryonic days 12, 14 and 16. Derived data was subjected to computational analysis in the form of principal component analysis followed by linear discriminant analysis.
Results: :
Observable differences in the elemental and sulfur species composition were observed over the developmental period, embryonic day 12 to embryonic day 16. The molecular signatures of chlorine, potassium, calcium, phosphorus and sulfate were found to be distinct with development. Notably, developmentally regulated alterations in thiols, organic monosulfides, ester sulfate and inorganic sulfate were observed in the developing chick.
Conclusions: :
Our findings establish the potential application of X-ray fluorescence microscopy and X-ray absorption near-edge structure spectroscopy for the analysis of bulk tissue and highlight their applicability in the life sciences. The chemical compositional and sulfur speciation alterations reported here provide a deeper understanding of the molecular basis of corneal embryogenesis during the transition from an immature opaque cornea to a mature transparent tissue. This study revealed transient molecular signatures and compositional changes which correlate with changes in corneal structure-function relationships.
Keywords: cornea: stroma and keratocytes • cornea: basic science