title: Basement membrane and matrix metalloproteinases in monocrotaline-induced liver injury.
abstract: Monocrotaline (MCT) is a pyrrolizidine alkaloid that causes liver injury in animals. In rats, injury is characterized by sinusoidal endothelial cell (SEC) damage and centrilobular parenchymal cell necrosis. Loss of endothelium is a possible outcome of the action of matrix metalloproteinases (MMPs), specifically MMP-9 from neutrophils and SECs and MMP-2 from SECs, on basement membrane collagen. Accordingly, the dynamics of MMPs in MCT-induced SEC damage were studied. Rats were treated with MCT (300 mg/kg, ip), and livers were collected at 8, 12, and 18 h. Immunofluorescence analysis of frozen sections of livers from MCT-treated rats revealed a progressive reduction in basement membrane heparan sulfate proteoglycan and collagen IV. A time-dependent increase in total type IV collagenase activity and MMP-9 content occurred in the livers of MCT-treated rats, as measured by fluorescent collagenase activity assay and gelatin zymography, respectively. Progressive neutrophil accumulation and activation in the liver after MCT treatment were demonstrated by an increased activity of myeloperoxidase and pronounced staining for hypochlorite-modified proteins generated via the myeloperoxidase-hydrogen peroxide-halide system. However, neutrophil depletion did not protect against MCT-induced SEC injury. Treatment of NP-26 cells, a sinusoidal endothelial cell line, with MCT resulted in dose-dependent release of MMP-9 from the cells. The results demonstrate the degradation of basement membrane components with a concurrent increase in the amount and activity of MMP-9, likely originating from sinusoidal endothelial cells, neutrophils, and probably other cell types. This suggests the possibility of a role for MMPs in the SEC detachment and loss that occurs during MCT hepatotoxicity.
authors.affiliation: Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan 48824, USA.
authors.forename: Umesh M
authors.initials: UM
authors.lastname: Hanumegowda
authors.forename: Bryan L
authors.initials: BL
authors.lastname: Copple
authors.forename: Masabumi
authors.initials: M
authors.lastname: Shibuya
authors.forename: Ernst
authors.initials: E
authors.lastname: Malle
authors.forename: Patricia E
authors.initials: PE
authors.lastname: Ganey
authors.forename: Robert A
authors.initials: RA
authors.lastname: Roth
mesh_terms: D000818:Animals; D001485:Basement Membrane / Q000187:drug effects / Q000378:metabolism; D002460:Cell Line; D024141:Collagen Type IV / Q000378:metabolism; D019812:Heparan Sulfate Proteoglycans / Q000378:metabolism; D007274:Injections, Intraperitoneal; D008099:Liver / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D016686:Monocrotaline / Q000633:toxicity*; D018375:Neutrophil Activation / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
chemical_list: D024141:Collagen Type IV; D019812:Heparan Sulfate Proteoglycans; D016686:Monocrotaline; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9