Wound healing in ovariectomized rats: effects of chemically modified tetracycline (CMT-8) and estrogen on matrix metalloproteinases -8, -13 and type I collagen expression.
Cutaneous wound healing is a complex process involving interactions of various cell types. Skin, in addition to certain other organs, is dependent on estrogen; and estrogen-deficiency is associated with impaired wound healing. Wound healing involves the action of collagenolytic matrix metalloproteinases (MMPs). We investigated the expression and localization of collagenolytic MMPs -8 and -13 by collagenase activity assay, Western immunoblot analysis, in situ hybridization and immunohistochemical staining as well as type I collagen by hydroxyproline content analysis and immunohistochemical staining in cutaneous wounds from aged Sham and ovarioectomized (OVX) rats. After wounding, OVX rats were treated with either placebo, chemically modified tetracycline-8 (CMT-8) or estrogen. We found that MMP-8 and MMP-13 mRNA were expressed in wound epithelium of all samples examined as evidenced by in situ hybridization. Type I collagen, which was abundant in all groups examined, was decreased in OVX rats, but was increased by both CMT-8 and estrogen treatments to the level of Sham group. Hydroxyproline analysis revealed similar results. Western blot data showed that all forms of MMP-8 and MMP-13 were clearly reduced in the CMT-8 treated group compared to OVX. Analysis of collagenolytic activity confirmed the decreased collagenolysis in skin wound extracts from CMT-treated rats when compared with skin wound extracts from OVX rats. Our results show for the first time that MMP-8 mRNA and protein are expressed in rat wound epithelium. We further show that CMT-8 and estrogen have a beneficial effect on skin wound healing in OVX rats by increasing the collagen content and reducing the MMP-mediated collagenolysis.
Pirilä
E
E
Department of Clinical Veterinary Sciences, University of Helsinki, Helsinki, Finland. pirila@hammas.helsinki.fi
Ramamurthy
N
N
Maisi
P
P
McClain
S
S
Kucine
A
A
Wahlgren
J
J
Golub
L
L
Salo
T
T
Sorsa
T
T
D000818:Animals; D003094:Collagen / Q000235:genetics*; D017364:Collagenases / Q000235:genetics* / Q000378:metabolism; D004847:Epithelial Cells / Q000187:drug effects / Q000473:pathology / Q000502:physiology; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D017403:In Situ Hybridization; D053509:Matrix Metalloproteinase 13; D020784:Matrix Metalloproteinase 8 / Q000235:genetics*; D010052:Ovariectomy; D011480:Protease Inhibitors / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012867:Skin / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D013754:Tetracyclines / Q000494:pharmacology*; D014158:Transcription, Genetic / Q000187:drug effects*; D014945:Wound Healing / Q000187:drug effects / Q000502:physiology*; D014947:Wounds and Injuries / Q000503:physiopathology
D004967:Estrogens; D011480:Protease Inhibitors; D013754:Tetracyclines; C117153:tetracycline CMT-8; D003094:Collagen; D017364:Collagenases; D053509:Matrix Metalloproteinase 13; C507083:Mmp13 protein, rat; D020784:Matrix Metalloproteinase 8