glycogen and Corneal-Injuries

This study assesses the impact of various forms of injury on matrix degrading enzymes in nutritionally compromised rat corneas. In vitamin A-deficient (nutritionally compromised) and normal control corneas, in vivo or ex vivo mild mechanical abrasion did not appreciably alter the activity of either the 65-kDa or the 92-kDa gelatinases. In contrast, after thermal injury, while no appreciable change was detected in activity associated with the 65-kDa gelatinase in either vitamin A-deficient or normal control corneas, 92-kDa gelatinolytic activity was consistently higher in corneas from both groups, although activity associated with nutritionally compromised corneas was much higher. In these corneas, thermal injury also induced the expression of two high molecular weight (approximately 130-kDa and 225-kDa) gelatinases and a 27-kDa caseinase. While gelatinases were totally inactivated by inhibitors of metalloproteinases such as 1,10-phenanthroline and Galardin MPI, the 27-kDa caseinase showed considerable susceptibility to a mixture of serine protease inhibitors (aprotinin, dichloro-isocoumarin and pA-PMSF [(4-amidino-phenyl)-methane-sulphonyl fluoride]. Furthermore, unactivated-lymphoreticular cells from either nutritionally compromised or normal control animals contained a 24- and 27-kDa caseinase, however most of the activity was due to the 24-kDa caseinase. In contrast, glycogen-activated lymphoreticular cells contained a preponderance of the 27-kDa caseinase. Activated-lymphoreticular cells also expressed 92-kDa, 130-kDa and 225-kDa gelatinases. The presence of low molecular weight caseinases in lymphoreticular cells implicates them as the source of these enzymes.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Cornea; Corneal Injuries; Corneal Ulcer; Eye Injuries; Gelatinases; Glycogen; Male; Metalloendopeptidases; Peptide Hydrolases; Rats; Rats, Sprague-Dawley; Reticulocytes; Vitamin A Deficiency

The regenerated epithelium derived from limbal epithelium was histologically and biochemically compared with epithelia regenerated from corneal and bulbar conjunctival epithelia. The histologic results indicated that regenerated epithelium of limbal origin increased in thickness with time after healing and showed no goblet cell appearance on the cornea. This suggests that regenerated epithelium from the limbus is more like regenerated epithelium of corneal origin than that of bulbar conjunctival origin. However, the glycogen content and protein pattern profile showed that regenerated epithelium of limbal origin had characteristics intermediate between those of corneal and bulbar conjunctival origin. Thus it is proposed that there are three distinct types of ocular surface epithelia--corneal, bulbar conjunctival, and limbal--and that limbal epithelium behaves differently from corneal and conjunctival epithelia in ocular surface wound healing.

Topics: Animals; Conjunctiva; Cornea; Corneal Injuries; Electrophoresis; Epithelium; Eye Proteins; Glycogen; Rabbits; Time Factors; Wound Healing

Topics: Contact Lenses, Hydrophilic; Corneal Injuries; Glycogen; Humans; Wound Healing; Wounds, Penetrating

The corneal epithelial cell has a unique sliding capability. The epithelial cell spreads and migrates in an amebic fashion without mitotic activity when the continuity of the epithelium is broken. This movement is demonstrated both in vivo and in vitro. Prompt sliding for sealing the wound defect is apparently the first step of the wound healing of the superficial cornea. Cut edges of collagen fibers show no sign of activity towards healing the wound. The energy source of the sliding is provided mainly from stored glycogen in the epithelial cells. Sliding is inhibited by removal of glycogen from the cell or by adding glycolytic enzyme inhibitors.

Topics: Animals; Cell Membrane; Cell Movement; Cornea; Corneal Injuries; Desmosomes; Endoplasmic Reticulum; Epithelial Cells; Epithelium; Eye Injuries; Glycogen; Golgi Apparatus; Intercellular Junctions; Iodobenzoates; L-Lactate Dehydrogenase; Mercuribenzoates; Mitosis; Rabbits; Ribosomes; Wound Healing

Topics: Animals; Cattle; Cornea; Corneal Injuries; Eye Burns; Eye Diseases; Eye Injuries; Glycogen; Graft vs Host Reaction; Histocytochemistry; Inflammation; Microscopy, Electron; Neutrophils; Phagocytosis; Rabbits; Rats