Removal of collagen bundles in murine uterus during postpartum involution

Shimizu, Kiyoshí; Hokano, Masami

doi:10.1002/ar.1092200205

Cited by 8 publications

(3 citation statements)

References 26 publications

(30 reference statements)

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“…The present study has shown that most of the collagen type III is removed from the endometrial stroma by day 10 postpartum, although this is not the case for the longitudinal smooth muscle. These findings agree with a previous report that collagen degradation occurs primarily in the endometrium (Shimizu & Hokano 1988). Removal of collagen type III from the endometrial stroma and from the endothelium of blood vessels, and also removal of collagen type III from the bundles and from the connective tissue band underlying the longitudinal smooth muscle layer, may contribute to the rapid decrease in uterine collagen.…”

Section: Discussionsupporting

confidence: 93%

“…Collagen contains all of the hydroxyproline in the body; the amount of hydroxyproline in an organ can be taken as a measure of its collagen content (Bloom & Fawcett 1975; Dawson & Milne 1978). The removal of collagen from the uterus during postpartum involution has been studied in rats (Harkness & Moralee 1956) and in mice (Shimizu & Hokano 1988).…”

Section: Introductionmentioning

confidence: 99%

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Morphometric and histochemical study of involution in the rat uterus after parturition

Elkhalil

Maejima

Aoyama

et al. 2005

Animal Science Journal

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Morphological changes to and collagen loss from the rat uterus during postpartum involution were investigated. The expression patterns of collagen type III and myeloperoxidase (MPO) were also determined. Morphological changes were studied on days 1, 3, 5, 10, 15, 20, 22 and 25 postpartum. As a control, diestrus rats’ uterine were used. Specimens from the uterine horn were embedded in paraffin, cut into 8 µm coronal sections, and stained with hematoxylin‐eosin. The thickness of the longitudinal and circular smooth muscle layers and of the endometrium were measured. The collagen content was determined using hydroxyproline analysis. Immunostaining was used to examine the expression of collagen type III on days 1, 3, 5, 10, 15 and 20 postpartum; and MPO on days 1, 3, 5, 10 and 22 postpartum. The thickness of the smooth muscle layers was found to decrease rapidly postpartum: the circular smooth muscle layer returned to that of a non‐pregnant, control uterus by day 5 postpartum and the longitudinal smooth muscle layer by day 15 postpartum. Eosinophilic cells were observed in the endometrial stroma adjacent to the myometrium on days 10, 15 and 20 postpartum, and were confirmed as collagenous cells. Immunostaining identified collagen type III positive cells in the vessel‐rich layer adjacent to the placental site on days 1, 3, 5 and 10 postpartum, and these cells were confirmed to be phagocytic. Postpartum reduction in the weight of the uterus was accompanied by decreases in both the collagen content and the thickness of the longitudinal and circular smooth muscle layers. Furthermore, the phagocytic cells were shown to express MPO during postpartum involution of the uterus.

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Section: Discussionsupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Morphometric and histochemical study of involution in the rat uterus after parturition

Elkhalil

Maejima

Aoyama

et al. 2005

Animal Science Journal

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“…In mice, the total uterine collagen mass increases up to 20-fold during pregnancy, and after parturition the uterus rapidly recovers to prepregnant size. This postpartum involution is accomplished within the first two days after giving birth and involves transcriptional activation of the collagenase gene and increased release of collagenase extracellularly followed by the massive degradation of most of the collagen deposited in the uterus within a few days (44,45). In mutant females, degradation of collagen was severely disturbed, leading to the accumulation of nodules in the uterine wall.…”

Section: Tissue Remodeling In the Adult Depends On A Functional Collamentioning

confidence: 99%

A targeted mutation at the known collagenase cleavage site in mouse type I collagen impairs tissue remodeling.

Liu

Byrne

et al. 1995

The Journal of Cell Biology

268

243

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Abstract. Degradation of type I collagen, the most abundant collagen, is initiated by collagenase cleavage at a highly conserved site between Gly775 and I1e776 of the od(I) chain. Mutations at or around this site render type I collagen resistant to collagenase digestion in vitro. We show here that mice carrying a collagenaseresistant mutant Colla-1 transgene die late in embryogenesis, ascribable to overexpression of the transgene, since the same mutation introduced into the endogenous Colla-1 gene by gene targeting permitted normal development of mutant mice to young adulthood. With increasing age, animals carrying the targeted mutation developed marked fibrosis of the dermis similar to that in human scleroderma. Postpartum involution of the uterus in the mutant mice was also impaired, with persistence of collagenous nodules in the uterine wall. AIthough type I collagen from the homozygous mutant mice was resistant to cleavage by human or rat fibroblast collagenases at the helical site, only the rat collagenase cleaved collagen trimers at an additional, novel site in the nonhelical N-telopeptide domain. Our results suggest that cleavage by murine collagenase at the N-telopeptide site could account for resorption of type I collagen during embryonic and early adult life. During intense collagen resorption, however, such as in the immediate postpartum uterus and in the dermis later in life, cleavage at the helical site is essential for normal collagen turnover. Thus, type I collagen is degraded by at least two differentially controlled mechanisms involving collagenases with distinct, but overlapping, substrate specificities.T YPE I collagen is among the most abundant components of the extracellular matrix of many tissues, particularly in skin, tendons, ligaments, uterus, large blood vessels and bone. The helical trimeric molecules of type I collagen comprise two al(I) chains and one ~2(I) chain, encoded by two separate genes, Colla-1 and Colla-2, respectively (50). In mice, type I collagen is first synthesized in the mesenchymal stroma of the head, heart and somites at day 8 of gestation (E8) and its production continues throughout development and postnatal life (27). It has been demonstrated that type I collagen is critical for bone development (9, 10), hematopoiesis (29, 37), integrity of the vascular system (29) and for mesenchymal-epithelial induction in organogenesis (6).The collagen content of different tissues during development and in adult animals is tightly regulated by coordinated processes of synthesis and degradation (2,8,57 teoporosis or inflammatory joint diseases) or excessive deposition (e.g. pulmonary fibrosis or scleroderma) (32, 39). The degradation of type I collagen requires the action of specific collagenases since native, triple-helical molecules are resistant to attack by proteolytic enzymes at 37°C and neutral pH. The collagenases are members of a family of proteinases, the metalloproteinases or matrixins, all of which contain a catalytic zinc-binding domain that includes the sequence moti...

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Reversal of muscle hypertrophy in the rat urinary bladder after removal of urethral obstruction

Gabella

Uvelius

1994

Cell Tissue Res

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We studied the ultrastructure of the bladder musculature after first inducing hypertrophy by means of urethral obstruction and subsequently removing the obstruction. With hypertrophy the bladder musculature increases ten-fold or more in volume; after de-obstruction approximately 4/5 of the hypertrophic muscle weight and volume is lost within six weeks. In spite of this very large decrease in muscle mass there is no degeneration of muscle cells or nerve endings or of other cell types in the de-obstructed bladder either at 5 days or at 6 weeks. The individual muscle cells are smaller in size than in the hypertrophic bladder but still larger than control muscle cells. The decrease in muscle cell size is more substantial than the decrease in muscle cell surface. There are no lysosomes or other signs of intracellular degradation in any cells of the muscle layer. The musculature contains a very large amount of intercellular material, mainly collagen. This study documents the great plasticity of the musculature in the reduction of muscle mass after de-obstruction. However, some of the fine structural features are almost as different from the controls as in the hypertrophic muscle.

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Removal of collagen bundles in murine uterus during postpartum involution

Cited by 8 publications

References 26 publications

Morphometric and histochemical study of involution in the rat uterus after parturition

Morphometric and histochemical study of involution in the rat uterus after parturition

A targeted mutation at the known collagenase cleavage site in mouse type I collagen impairs tissue remodeling.

Reversal of muscle hypertrophy in the rat urinary bladder after removal of urethral obstruction

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