Rebound elevation of fibronectin after tissue injury and ischemia: role of fibronectin synthesis.
Plasma fibronectin (pFn) stimulates macrophage phagocytosis of tissue debris; pFn deposition in tissues may influence vascular integrity. Although the acute depletion of pFn after surgery and/or injury has been described, less attention has been given to the rebound hyperfibronectinemia presumably "triggered" by the early pFn depletion. Using a model that compartmentalized the site of tissue injury and thus attenuated the initial pFn depletion, we studied this rebound elevation of pFn in anesthetized rats (250-350 g) after the surgical trauma of groin dissection alone (sham group) or surgery coupled with 4 h of hindlimb ischemia (experimental group). Nonoperated control rats were also anesthetized. Shams had baseline (preoperative) 6-, 8-, and 22-h postoperative pFn levels of 573 +/- 61, 598 +/- 62, 695 +/- 57, and 929 +/- 87 micrograms/ml, respectively. In the surgery-ischemia group, pFn also elevated to 1,117 +/- 40 micrograms/ml at 22 h postsurgery. Nonoperated control rats (only anesthetized) had no elevation of pFn. Intravenous infusion of gelatin-coated lipid particles (50 mg/100 g) depleted pFn by 89.3% but was unable to prevent the rebound elevation of pFn. The blood clearance of 125I-labeled pFn was very similar in control, sham, and experimental rats. In contrast, pFn synthesis over the 22-h period was dramatically altered and equal to 2.12 +/- 0.16, 3.40 +/- 0.56, and 4.49 +/- 0.17 mg pFn synthesized/100 g body wt, in control, sham, and experimental rats respectively. Thus a rapid increase in pFn synthesis contributes to the rebound hyperfibronectinemia after sublethal surgical injury.(ABSTRACT TRUNCATED AT 250 WORDS)
Thompson
P N
PN
Department of Physiology and Cell Biology, Albany Medical College of Union University, New York 12208.
Cho
E
E
Blumenstock
F A
FA
Shah
D M
DM
Saba
T M
TM
D000818:Animals; D005217:Fat Emulsions, Intravenous; D005353:Fibronectins / Q000096:biosynthesis / Q000097:blood* / Q000378:metabolism; D005780:Gelatin; D006119:Groin / Q000601:surgery*; D006614:Hindlimb / Q000098:blood supply*; D007511:Ischemia / Q000097:blood* / Q000378:metabolism; D008297:Male; D011184:Postoperative Period; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values; D014018:Tissue Distribution
D005217:Fat Emulsions, Intravenous; D005353:Fibronectins; D005780:Gelatin