Dynamic in vivo changes in tissue inhibitors of metalloproteinases 1 and 2, and matrix metalloproteinases 2 and 9, during prostaglandin F(2alpha)-induced luteolysis in sheep.
Prostaglandin F(2alpha) (PGF(2alpha)) typically initiates a cascade of events that leads to the functional and structural demise of the corpus luteum. A sheep model was used in which a 1-h, systemic infusion of PGF(2alpha) (20 microg/min) is given at midcycle. Such an infusion mimics the onset of spontaneous luteolysis by causing a transient decrease in peripheral plasma progesterone, which reaches a nadir ( approximately 60% of controls) at 8 h but returns to control levels by 16-24 h. We investigated whether PGF(2alpha) also influenced the endogenous protein levels of tissue inhibitors of metalloproteinases, TIMP-1 and TIMP-2, and matrix metalloproteinases, MMP-2 and MMP-9, all of which have been implicated in remodeling of the extracellular matrix (ECM). Corpora lutea (Day 11) were collected at 0 h and at 1, 8, 16, and 24 h post-PGF(2alpha) infusion (n = 3 sheep at each time). Immunoblot analysis revealed an immediate and precipitous decline in TIMP-1 (30 kDa) and TIMP-2 (19 kDa) protein levels (60% and 90%, respectively; P < 0.05) at the 1-h time point and remained depressed at 8 h (P < 0.05). Gelatin zymography and other procedures identified three MMPs (85, 70, and 64 kDa), which were shown to be the latent form of MMP-9 and the active and latent forms of MMP-2, respectively. In contrast to the rapid decrease in TIMP-1 and -2 levels, an increase in MMP-2 activity (165% of controls, P < 0.05) occurred at 8 h, which corresponded to the nadir in plasma progesterone. These early changes in TIMPs and MMPs indicate that alterations in the structure of the ECM by PGF(2alpha) may play a hitherto unsuspected role in the subsequent process of functional luteolysis.
Towle
Theresa A
TA
Department of Animal & Nutritional Sciences, Kendall Hall, University of New Hampshire, 129 Main Street, Durham, NH 03824, USA.
Tsang
Paul C W
PC
Milvae
Robert A
RA
Newbury
Michelle K
MK
McCracken
John A
JA
D000818:Animals; D003338:Corpus Luteum / Q000187:drug effects* / Q000378:metabolism; D015237:Dinoprost / Q000494:pharmacology*; D005260:Female; D015151:Immunoblotting; D007700:Kinetics; D008186:Luteolytic Agents / Q000494:pharmacology*; D020778:Matrix Metalloproteinase 2 / Q000096:biosynthesis*; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis*; D061965:Matrix Metalloproteinase Inhibitors; D010618:Phenanthrolines / Q000494:pharmacology; D011247:Pregnancy; D011374:Progesterone / Q000097:blood; D011480:Protease Inhibitors / Q000494:pharmacology; D012756:Sheep; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000096:biosynthesis*; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000096:biosynthesis*
D008186:Luteolytic Agents; D061965:Matrix Metalloproteinase Inhibitors; D010618:Phenanthrolines; D011480:Protease Inhibitors; D019715:Tissue Inhibitor of Metalloproteinase-1; D019716:Tissue Inhibitor of Metalloproteinase-2; D011374:Progesterone; D015237:Dinoprost; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9; C025205:1,10-phenanthroline