-Unfixed-cryostat-sections-from-4-animals-per-month-of-pregnancy-and-5-animals-per-peripartal-group-in-total-51-pregnancies-were-used-to-immunolocalize-collagen-types-I-III-and-IV-by-an-indirect-FITC-method-x

Collagen types I and III co-localize within the uterus. The tensile strength of the pregnant uterus is mainly represented by high contents of collagen type I within the allantochorion and subepithelial endometrial and subserosal meshes. Chorionic villi are fixed within caruncular crypts by two mechanisms: crypt openings are narrow and supplied with thick edges containing collagen types I and III. Collagen type IV contributes to all basement membranes and encloses connective tissue cells within the maternal crypt stroma, the stratum compactum and the perimetrial connective tissue. At term, fetal membranes and placentomes are edematous and at the light-microscopic level no distinct differences are visible between connective tissue fibers of placentomes from animals retaining the fetal membranes and those releasing them in time. In conclusion, collagen types I, III and IV exhibit type- and location-specific distribution patterns within the uterus of the pregnant cow.

These may additionally be influenced by the stage of pregnancy, thus reflecting the dynamic processes at the stromal level.Loss of Discoidin Domain Receptor 1 Predisposes Mice to Periodontal Breakdown.Columbia University Irving Medical Center, New York, NY, USA.Piracicaba Dental School, University of Campinas-UNICAMP, Piracicaba, SP, The discoidin domain receptors, DDR1 and DDR2, are nonintegrin collagen receptors and tyrosine kinases. DDRs regulate cell functions, and their extracellular domains affect collagen fibrillogenesis and mineralization. Based on the collagenous nature of dentoalveolar tissues, we hypothesized that DDR1 plays an important role in dentoalveolar development and function. Radiography, micro-computed tomography (micro-CT), histology, histomorphometry, in situ hybridization (ISH), immunohistochemistry (IHC), and transmission electron microscopy (TEM) were used to analyze Ddr1 knockout (Ddr1-/-) mice and wild-type (WT) controls at 1, 2, and 9 mo, and ISH and quantitative polymerase chain reaction (qPCR) were employed to assess Ddr1/DDR1 messenger RNA expression in mouse and human tissues.

Radiographic images showed normal molars but abnormal mandibular condyles, as well as alveolar bone loss in Ddr1-/- mice versus WT controls at 9 mo. Histological, histomorphometric, micro-CT, and TEM analyses indicated no differences in enamel or dentin Ddr1-/- versus WT molars. Total volumes (TVs) and bone volumes (BVs) of subchondral and ramus bone of Ddr1-/- versus WT condyles were increased and bone volume fraction (BV/TV) was reduced at 1 and 9 mo. There were no differences in alveolar bone volume at 1 mo, but at 9 mo, severe periodontal defects and significant alveolar bone loss (14%; P < 0001) were evident in Ddr1-/- versus WT mandibles. Histology, ISH, and IHC revealed disrupted junctional epithelium, connective tissue destruction, bacterial invasion, increased neutrophil infiltration, upregulation of cytokines including macrophage colony-stimulating factor, and 3-fold increased osteoclast numbers (P < 05) in Ddr1-/- versus WT periodontia at 9 mo. In ordinary squalane cleanser , ISH and qPCR revealed Ddr1 expression in basal cell layers of the oral epithelia and in immune cells. We confirmed a similar expression pattern in human oral epithelium by ISH and qPCR.

We propose that DDR1 plays an important role in periodontal homeostasis and that absence of DDR1 predisposes mice to Conflict of interest statement: The authors declare no potential conflicts of interest with respect to the authorship and/or publication of this article.8981. J Biol Chem. 1983 Dec 10;258(23):14162-5.The collagen substrate specificity of rat uterus collagenase.The collagen substrate specificity of rat uterus collagenase was studied as a function of both collagen type and species of substrate origin. For each collagen examined, values for the basic kinetic parameters, Km and Vmax (kcat), were determined on collagen in solution at 25 degrees C.

In squalene , Lineweaver-Burk plots were linear and rat uterus collagenase behaved as a normal Michaelis-Menten enzyme. Collagen types I, II, and III of all species tested were degraded by rat uterus collagenase. Collagen types IV and V were resistant to enzymatic attack. Both enzyme-substrate affinity and catalytic rates were very similar for all susceptible collagens (types I-III). Values for Km ranged from 0 to 2 X 10(-6) M. Values for kcat varied from 10 to 28 h-1. The homologous rat type I collagen was no better a substrate than the other animal species type I collagens.

The ability of rat uterus collagenase to degrade collagen types I, II, and III with essentially the same catalytic efficiency is unlike the action of human skin fibroblast collagenase or any other interstitial collagenase reported to date. The action of rat uterus collagenase on type I collagen was compared to that of human skin fibroblast collagenase, with regard to their capacity to cleave collagen as solution monomers versus insoluble fibrils. Both enzymes had essentially equal values for kcat on monomeric collagen, yet the specific activity of the rat uterus collagenase was 3- to 6-fold greater on collagen fibrils than the skin fibroblast enzyme.