Effect of Force Level on Synthesis of Type III and Type I Collagen in Mouse Interparietal Suture

Abstract

Nine-week-old Swiss male white mice were divided into groups killed after time intervals of force application of six h, and one, three, five, seven, ten, 14, 21, and 28 days. Each group had 45 animals: three control, three sham-operated, and three experimental animals for each of the five force levels: 50 g, 35 g, 25 g, 15 g, and 5 g. The experimental animals had helical springs placed surgically in their calvaria for expansion of the interparietal suture. The sham-operated animals received inactive springs. Control animals were at the same age as the experimental and sham-operated animals. After death, the amount of sutural expansion was measured, and the calvaria with the implanted springs were explanted into Trowell-type organ culture dishes. [14C]-glycine was added for two h after 60 min of culture for all explants. The rate of suture expansion was directly proportional to the force value of the tensile stress, and a maximum 2.0-mm expansion was achieved for all force levels by the 28th day. Sutural collagen was solubilized by limited pepsin digestion, and radiolabeled types I and III alpha-chains were separated by SDS-PAGE, visualized fluorographically, and measured densitometrically. All the experimental and sham-operated animals responded with a rapid rise followed by an almost equally rapid fall in the proportion of newly-synthesized type III collagen before becoming stabilized for the rest of the experimental period at a level that was significantly higher than that of the control and sham-treated animals of the same age.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of matrix metalloproteinase genes in the rat intramembranous bone during postnatal growth and upon mechanical stresses

“…The present observation of mechanical modulation of MMP-2 in the PFS in vivo is consistent with altered expression of MMPs in isolated suture explants by continuous tensile forces (Meikle et al, 1984;Green et al, 1990). In addition to MMPs, type I and type III collagen synthesis is also modulated by tensile stresses applied to cranial suture explants (Meikle et al, 1984;Miyawaki and Forbes, 1987;Yen et al, 1989). Thus, the presently observed mechanical modulation of MMP-2 expression likely is an event in the process of mechanotransduction of sutural mechanical stresses (Mao, 2002).…”

Force-Induced Craniosynostosis in the Murine Sagittal Suture

“…Specifically, changes in calcium homeostasis and permeability have been isolated,39 in addition to apoptotic induction,40 and collagen-matrix deposition 41. Similarly, many discreet phenotypic changes in calvarial morphology have been observed in response to mechanical loads, including: increased bone volume and mineral apposition rate,42, 43–44 augmented osteoprogenitor45 and fibroblast cell numbers,46 increased alkaline phosphatase activity,47,48 praline incorporation47,48 and collagen matrix production 44,49. In light of our results, these well-documented structural changes lend credence to the potential role of mechanotransduction in non-syndromic craniosynostosis.…”

Sutural Distraction Osteogenesis (SDO) Versus Osteotomy Distraction Osteogenesis (ODO) for Midfacial Advancement: A New Technique and Primary Clinical Report

“…There are also some reports dealing with other sutures. 21,[46][47][48][49][50] This traditional management of maxillary advancement commonly uses a face bow or face mask, an intraoral appliance fixed to the dental arch, and elastics. It has little influence on the retrograde maxillary skeleton 51 because of the lower position of the distraction force ( Fig 20A).…”