Reduced Levels of Tissue Inhibitors of Metalloproteinases in UVB-Irradiated Corneal Epithelium.
Tissue inhibitors of metalloproteinases (TIMPs) are the major endogenous regulators of metalloproteinase activity in tissues. TIMPs are able to inhibit activity of all known matrix metalloproteinases (MMPs) and thus participate in controlling extracellular matrix synthesis and degradation. We showed previously elevated expressions of MMPs in the rabbit corneal epithelium upon UVB exposure and suggested that these enzymes might be involved in corneal destruction caused by excessive proteolysis. The aim of this study was to investigate TIMPs in the corneal epithelium after UV irradiation using immunohistochemical and biochemical methods. We found that as compared to control rabbit corneas where relatively high levels of TIMPs were present in the epithelium, repeated irradiation of the cornea with UVB rays (not with UVA rays of similar doses) significantly decreased TIMPs in corneal epithelial cells. The results of this study point to the suggestion that the decrease in TIMPs in the corneal epithelium after UVB irradiation contributes to increased proteolytic activity of MMPs in UVB-irradiated corneal epithelium found previously.
Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, Liběchov, Czech Republic. ardan@iapg.cas.cz.
Taras
T
Ardan
Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, Liběchov, Czech Republic.
Lucie
L
Němcová
Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, Liběchov, Czech Republic.
Božena
B
Bohuslavová
Faculty Hospital Královské Vinohrady, Prague, Czech Republic.
Adéla
A
Klezlová
Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
Štěpán
Š
Popelka
Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
Hana
H
Studenovská
Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, Liběchov, Czech Republic.
Eva
E
Hrnčiarová
Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
Jitka
J
Čejková
Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, Liběchov, Czech Republic.
Jan
J
Motlík
D000818:Animals; D019573:Epithelium, Corneal / Q000201:enzymology / Q000528:radiation effects*; D007150:Immunohistochemistry; D020782:Matrix Metalloproteinases / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011817:Rabbits; D060888:Real-Time Polymerase Chain Reaction; D014466:Ultraviolet Rays
D012333:RNA, Messenger; D020782:Matrix Metalloproteinases