Effects of divalent cations on bovine corneal stromal swelling rates.
OBJECTIVE
The corneal stroma swells with edema fluid due to electrostatic repulsion of its negatively charged glycosaminoglycans, and divalent metal cations inhibit edema development. We investigated whether or not nonmetal divalent cations might also inhibit edema development.


METHODS
We investigated the hydration rates of stromas bathed in phosphate-buffered saline (PBS) or phosphate-buffered magnesium sulfate, calcium chloride, hexamethonium dihydrochloride, putrescine dihydrochloride, and ethylenediamine hydrochloride solutions at pH 7.35-7.4.


RESULTS
Hydration rate was fastest in PBS and slower in divalent cation salt solutions (p < 0.05). All metal and nonmetal divalent cations inhibited swelling rates compared to PBS. Ethylenediamine is not divalent at physiological pH and did not significantly inhibit swelling.


CONCLUSIONS
All the divalent cations appear to decrease swelling relatively equally, probably by shielding negative charges on GAGs, reducing their electrostatic repulsions.
Hogan
Zachary Scott
ZS
Biophysics and Physiology Laboratory, Department of Biology, University of West Georgia, Carrollton, Georgia 30118, USA.
Brown
Kimberly Leigh
KL
Ishola
Adenike
A
Gatimu
Jane
J
Flucker
LaQuetta
L
Huff
Joseph William
JW
D000818:Animals; D002122:Calcium Chloride / Q000494:pharmacology; D002413:Cations, Divalent / Q000494:pharmacology*; D002417:Cattle; D015715:Corneal Edema / Q000139:chemically induced* / Q000175:diagnosis; D003319:Corneal Stroma / Q000187:drug effects* / Q000473:pathology; D005029:Ethylenediamines / Q000494:pharmacology; D018738:Hexamethonium / Q000494:pharmacology; D008278:Magnesium Sulfate / Q000494:pharmacology; D011700:Putrescine / Q000494:pharmacology
D002413:Cations, Divalent; D005029:Ethylenediamines; D018738:Hexamethonium; C031234:ethylenediamine; D008278:Magnesium Sulfate; D002122:Calcium Chloride; D011700:Putrescine