Stability of elastin in the developing mouse aorta: a quantitative radioautographic study

Elastic lamina growth during development and the ultimate stability of elastin in the mouse aortic media was investigated by light and electron microscopic radioautography. Following a single subcutaneous injection of l-[3,4-3H]valine at 3 days of age, animals were killed at 9 subsequent time intervals up to 4 months of age. One day after injection, radioautographic silver grains were primarily observed over the elastic laminae; however, silver grains were also seen over the smooth muscle cells and extracellular matrix. By 21 to 28 days of age, the silver grains were almost exclusively located over the elastic laminae. From 28 days to 4 months of age, the distribution of silver grains appeared relatively unchanged. Quantitation of silver grain number/μm2 of elastin showed a steady decrease in the concentration of silver grains associated with the elastic laminae from 4 to 21 days of age. After this time, no significant difference in silver grain concentration was observed. Since the initial decrease in grains/μm2 of elastin corresponds to a period of rapid post-natal growth, the decrease is likely to be a result of dilution of the radiolabel due to new elastin synthesis. With the assumption that little or no significant turnover occurs during this time, a constant growth rate of 4.3% per day was predicted by linear regression analysis. Since no significant difference in the concentration of silver grains was observed from 28 to 118 days of age, no new growth or turnover of elastin can be said to occur during this time period. This is supported by the observation that animals injected with radiolabeled valine at 28 days and 8 months of age showed no significant incorporation of radiolabel into the elastic laminae. The results from this study present the first long-term radioautographic evidence of the stability of aortic elastin and emphasize that initial deposition of elastin and proper assembly of elastic laminae is a critical event in vessel development.

[1]  R. Gerrity,et al.  The aortic tunica media of the developing rat. I. Quantitative stereologic and biochemical analysis. , 1975, Laboratory investigation; a journal of technical methods and pathology.

[2]  H. Nakamura,et al.  Electron microscopic study of the prenatal development of the thoracic aorta in the rat. , 1988, The American journal of anatomy.

[3]  J. L. Alford,et al.  Developmental changes in collagen and elastin biosynthesis in the porcine aorta. , 1986, Developmental biology.

[4]  C. Berry,et al.  The growth and development of the rat aorta. II. Changes in nucleic acid and scleroprotein content. , 1972, Journal of anatomy.

[5]  Gerrity Rg,et al.  The aortic tunica media of the developing rat. I. Quantitative stereologic and biochemical analysis. , 1975 .

[6]  F. Keeley.  The synthesis of soluble and insoluble elastin in chicken aorta as a function of development and age. Effect of a high cholesterol diet. , 1979, Canadian journal of biochemistry.

[7]  D. Volpin,et al.  Fine mapping of tropoelastin-derived components in the aorta of developing chick embryo , 1987, The Histochemical Journal.

[8]  C. Cross,et al.  Elastin metabolism in rodent lung. , 1981, Biochimica et biophysica acta.

[9]  G. M. Fischer,et al.  In vivo effects of sex hormones on aortic elastin and collagen dynamics in castrated and intact male rats. , 1978, Endocrinology.

[10]  R. Gerrity,et al.  The aortic tunica media of the developing rat. II. Incorporation by medial cells 3-H-proline into collagen and elastin: autoradiographic and chemical studies. , 1975, Laboratory investigation; a journal of technical methods and pathology.

[11]  H. Slack.  Metabolism of Elastin in the Adult Rat , 1954, Nature.

[12]  G. M. Fischer.  Dynamics of collagen and elastin metabolism in rat aorta. , 1971, Journal of applied physiology.

[13]  R. Walford,et al.  STABILITY OF LABELED AORTIC ELASTIC TISSUE WITH AGE AND PREGNANCY IN THE RAT. , 1964, Archives of pathology.

[14]  B. L. Langille,et al.  Rapid accumulation of elastin and collagen in the aortas of sheep in the immediate perinatal period. , 1991, Circulation research.

[15]  C. Berry,et al.  Nucleic acid and scleroprotein content of the developing human aorta , 1972, The Journal of pathology.

[16]  B. Kopriwa.  A reliable, standardized method for ultrastructural electron microscopic radioautography , 1973, Histochemie.

[17]  J A Pierce,et al.  Marked longevity of human lung parenchymal elastic fibers deduced from prevalence of D-aspartate and nuclear weapons-related radiocarbon. , 1991, The Journal of clinical investigation.

[18]  E. Reynolds.  THE USE OF LEAD CITRATE AT HIGH pH AS AN ELECTRON-OPAQUE STAIN IN ELECTRON MICROSCOPY , 1963, The Journal of cell biology.

[19]  R. Ross,et al.  THE SMOOTH MUSCLE CELL I. In Vivo Synthesis of Connective Tissue Proteins , 1971 .

[20]  K. T. Kao,et al.  Connective Tissue V. Comparison of Synthesis and Turnover of Collagen and Elastin in Tissues of Rat at Several Ages.∗ , 1961, Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine.

[21]  R. Garrone,et al.  A routine method for contrasting elastin at the ultrastructural level. , 1984, The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society.

[22]  F. Keeley,et al.  Measurement of the absolute synthesis of soluble and insoluble elastin by chick aortic tissue. , 1983, Canadian journal of biochemistry and cell biology = Revue canadienne de biochimie et biologie cellulaire.

[23]  R. Rucker,et al.  Arterial elastin synthesis in the young chick. , 1976, Biochimica et biophysica acta.

[24]  C. P. Leblond,et al.  IMPROVEMENTS IN THE COATING TECHNIQUE OF RADIOAUTOGRAPHY , 1962 .

[25]  L. Sandberg,et al.  Ultrastructural studies on early elastogenesis , 1966 .

[26]  R. Rucker,et al.  Structure and metabolism of arterial elastin. , 1977, International review of experimental pathology.

[27]  M. Lefevre,et al.  Aorta elastin turnover in normal and hypercholesterolemic Japanese quail. , 1980, Biochimica et biophysica acta.

[28]  Keeley Fw.  The synthesis of soluble and insoluble elastin in chicken aorta as a function of development and age. Effect of a high cholesterol diet. , 1979 .

[29]  E. Davis,et al.  Smooth muscle cell to elastic lamina connections in developing mouse aorta. Role in aortic medial organization. , 1993, Laboratory investigation; a journal of technical methods and pathology.