Matrix metalloproteinase-2 activity, protein, mRNA, and tissue inhibitors in small arteries from pregnant and relaxin-treated nonpregnant rats.
Vascular gelatinase activity is essential for pregnancy- and relaxin (Rlx)-induced renal vasodilation and hyperfiltration in rats. The objective of this study was to further elucidate the mechanisms for the increase in vascular matrix metalloproteinase (MMP)-2 activity caused by pregnancy and Rlx. We first corroborated our earlier work by showing that pro- and active forms of MMP-2 were increased in small renal arteries from pregnant compared with virgin rats and Rlx-treated compared with vehicle-treated nonpregnant rats. We next investigated other artery types and showed that MMP-2 activity was upregulated in mesenteric arteries from pregnant rats (pro-MMP-2 by 50% and active MMP-2 by 40%, both P<0.05) and from Rlx-treated nonpregnant rats (pro-MMP-2 by 50% and active MMP-2 by 90%, both P<0.005) compared with their respective controls. To corroborate these results obtained by gelatin zymography, pro-MMP-2 protein was determined by Western analysis in the same small arteries. Pro-MMP-2 protein was increased in small renal arteries from pregnant compared with virgin rats and from Rlx- compared with vehicle-treated nonpregnant rats: pro-MMP-2-to-beta-actin ratio=0.29 vs. 0.21 (P<0.01) and 0.43 vs. 0.32 (P<0.005). Findings were similar for mesenteric arteries. MMP-2 mRNA as measured by real-time PCR was increased in small renal arteries from pregnant and Rlx-treated nonpregnant rats compared with their respective controls. There were no significant differences in tissue inhibitor of metalloproteinase (TIMP-1 or TIMP-2) activity by reverse zymography in small renal arteries. Thus increases in MMP-2 mRNA and protein expression are major factors contributing to increased MMP-2 activity in small arteries from pregnant and Rlx-treated nonpregnant rats.
Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Pittsburgh School of Medicine, PA 15213, USA.
Arundhathi
A
Jeyabalan
Laurie J
LJ
Kerchner
Michelle C
MC
Fisher
Jonathan T
JT
McGuane
Ketah D
KD
Doty
Kirk P
KP
Conrad
D000818:Animals; D001158:Arteries / Q000737:chemistry* / Q000166:cytology / Q000502:physiology; D004730:Endothelium, Vascular / Q000737:chemistry / Q000166:cytology / Q000502:physiology; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D005260:Female; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D008638:Mesenteric Arteries / Q000737:chemistry / Q000166:cytology / Q000502:physiology; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis* / Q000235:genetics; D051381:Rats; D012065:Relaxin / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000032:analysis; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000032:analysis; D019714:Tissue Inhibitor of Metalloproteinases / Q000032:analysis*; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology
D012333:RNA, Messenger; D019715:Tissue Inhibitor of Metalloproteinase-1; D019714:Tissue Inhibitor of Metalloproteinases; D019716:Tissue Inhibitor of Metalloproteinase-2; D012065:Relaxin; D020778:Matrix Metalloproteinase 2