Total Amount Of Collagen Research Articles

Evidence of early structural change in the artery wall of two-kidney one-clip Goldblatt hypertensive rats.

Vascular structural changes were studied during the development of two-kidney one-clip renal hypertension. The weight of the arteries and the concentration and total amount of ribonucleic acid, deoxyribonucleic acid, alkali-soluble proteins, collagen and elastin of the vascular wall were measured. Tritiated thymidine uptake was also determined 15 and 30 days after clipping. Hypertension developed in 58% of the animals while the rest remained normotensive. A significant increase in artery weight and in the total amount of nucleic acids and proteins was found in hypertensive rats. The uptake of 3H thymidine by the arteries of hypertensive rats was significantly increased 15 days after clipping. This increment showed a significant correlation with blood pressure levels. Present data seem to indicate that the increase in vessel wall dimensions observed is partly due to an increase in the number of smooth muscle cells during the acute phase; this alteration appears to be mainly due to the rise in blood pressure.

Lung injury induced by mycobacterial cell walls: Effects on connective tissue

Intravenous injection of cell walls from Mycobacterium bovis strain BCG results in increased lung mass in the rat 4 months after injection. Histologically, there is a simultaneous increase in interstitial material and the formation of granulomata. The granulomata do not show increased staining for collagen by a trichrome stain. Prominent reticulin is present in the granulomata as shown by a silver stain. Lung dry weight is significantly increased 4 months after the injection of 300 μg cell walls; the total amount of collagen is significantly increased, but its concentration (amount per mg dry weight) is similar to that of controls. At 6 months, lung collagen amounts in BCG-treated animals are not significantly different from those of controls. By 10 months the granulomata largely disappear, lung architecture returns to normal, and lung collagen amounts are at control levels. In this model of lung injury, increases in lung connective tissue proteins are not selective and they do not persist as the lung returns to normal histologically.

Biochemical and histological changes in pulmonary fibrosis induced in rabbits with intratracheal bleomycin.

Pulmonary fibrosis was induced in rabbits by an intratracheal instillation of bleomycin. Histologically, at 2 weeks there was inflammation but only limited evidence of increased collagen deposition; at 8 weeks the inflammatory response had subsided and increased collagen deposition, characteristic of early interstitial fibrosis, was observed. Biochemical analyses showed bleomycin treatment caused marked increases in the total amounts of RNA, DNA, mixed protein, collagen and elastin when compared to controls (P less than 0.001 in all cases). Furthermore the increases were essentially complete by 2 weeks where the contents had increased by 110 +/- 13%, 60 +/- 11%, 148 +/- 12%, 94 +/- 15% and 89 +/- 11% respectively (P less than 0.001 in all cases). When collagen and elastin were expressed as concentrations with respect to wet weight, total protein or DNA content, the changes were not statistically significant. No changes were observed in the relative amounts of type I and type III collagen. It is concluded that: (1) compared to biochemical analysis, histology is relatively insensitive in detecting the early increases in connective tissue proteins; (2) measurements of lung collagen and elastin should be expressed as total lung contents wherever possible; the concentration of these proteins may remain unchanged, especially in the early stages of fibrosis, due to concomitant increases in other lung constituents; (3) changes in the relative amounts to types I and III collagens do not play a major role in the pathology of this form of pulmonary fibrosis.

Collagen synthesis and content in right ventricular hypertrophy in the dog.

The fractional synthesis rate of collagen (the percent of total ventricular collagen synthesized in one day) was measured in the hearts of normal dogs and those with pulmonary artery stenosis using a continuous 6-h intravenous infusion of [14C]proline. The fractional synthesis rate in normal ventricles was slow, 0.56%/day, and it increased eightfold to 4.8%/day in the hypertrophying right ventricle after 5 days. After 12 and 28 days the synthesis rate was still significantly greater than in the control left ventricle, being 2.6 and 1.3%/day, respectively. However, the synthesis rate of noncollagen protein was significantly greater than normal at 5 days only. The collagen content (expressed as a mass fraction) of the right ventricle decreased over the first 12 days of hypertrophy but by 28 days was restored to the normal right ventricular value of 9.6 mg/g wet wt tissue. The total amount of collagen in the hypertrophied ventricle calculated from the synthesis rates was in accord with that measured chemically. In normal dogs the collage content of the right ventricle was greater than that of the left, and the epicardium contributed substantially to the total collagen in the ventricular walls.

Enzyme changes during experimental silicotic fibrosis: I. PZ peptidase and collagen deposition in the lungs

In various time intervals from 2 to 22 weeks after intratracheal quartz dust instillation (25 mg DQ 12) the content of collagen proteins, deoxyribonucleic acid, soluble proteins, and collagen peptidase activity (PZ substrate) in rat lungs were estimated. In the period from 2 to 8 weeks the total amount of collagen as well as enzyme activity increased in parallel by about 200% in comparison to controls. In later periods (16 and 22 weeks after dust instillation) disproportions occurred. Collagen content in silicotic lungs continued to increase; the total activity of collagen peptidase in lungs started to decrease as did the specific enzyme activity. There was also observed a decrease in the content of lung proteins soluble in isotonic KCl. From 6 weeks onward, disc electrophoresis showed changes in the proportions of these proteins in dusted rats. The changes were particularly manifest in postalbumins, α 2- and γ-globulins, indicating more severe disorders in lung metabolism. There were found no differences in the amount and in the electrophoretic characteristics of serum proteins as well as in specific activity of PZ peptidase in serum of control and quartz-dusted rats. Neither control nor silicotic rat sera disclosed inhibitory effects on the activity of lung PZ peptidase. It appears that the increase of collagen proteins in lungs of animals dusted with quartz is also accelerated by the impairment of collagen breakdown.

Metabolism of collagen and muscle protein of adult rats in protein depletion and repletion.

The effect of protein depletion and repletion on the contents of rat body collagen and muscle protein has been investigated. Adult male rats were placed on a protein-free diet for 64 days, and thereafter fed with a 20% casein diet for 83 days. Total nitrogen, hydr oxyproline and Nτ-methylhistidine were determined in several tissues. Skin collagen was fractionated into neutral salt-soluble, acid-soluble and insoluble collagen.In prolonged protein depletion, the total amounts of liver protein, skin collagen and muscle protein were markedly decreased, while carcass collagen (excluding skin) showed little effect. The concentrations of skin and carcass collagen were significantly increased in protein depleted rats. Some differences in metabolism between skin collagen and other carcass collagen were discussed.After 64 days of depletion, refeeding on an adequate protein diet brought about a rapid increase in body weight, liver protein and muscle protein. Skin collagen did not increase in the early period of refe...

The rapid determination of microgram amounts of total collagen in pathological lesions

A rapid and convenient method for the determination of collagen in tissue is presented. The simple and reproducible method for hydrolysis allows many specimens to be processed simultaneously, and the rapid spectrophotometric determination of hydroxyproline, the presumptive index for collagen, ensures accurate and precise results.

CONNECTIVE TISSUE PROFILES OF VARIOUS RAW SAUSAGE MATERIALS

ABSTRACT21 different sausage meats were chemically analyzed to determine the amounts of total collagen, insoluble collagen, and percentage soluble collagen present in each meat. A simple cookout test was also conducted to determine its usefulness in evaluating the bind characteristics of raw sausage materials. Values for total collagen, insoluble collagen, and percentage soluble collagen were quite variable among the meats sampled. Of the three collagen profile components studied, only percentage soluble collagen was observed to, be highly related to the binding characteristics of meat. Values for milliliters of fat and water lost during cooking were not significantly related to bind values. This study indicates a need for additional research to investigate the role of collagen profile components in the I formation of sausage batters.

Collagen and non-collagen protein synthesis in developing lung exposed to tobacco smoke

The present investigation was conducted to determine the rate of collagen and non-collagen protein synthesis by rat lung under in vitro conditions. The rate of synthesis of non-collagen protein was greater than the rate of collagen synthesis in animals between 1 and 95 days of age. Synthesis of both types of proteins was highest in 1-day-old animals. Rate of synthesis of non-collagen protein was markedly diminished after 7 days of age and that of collagen decreased after 14 days. Per gram lung, the total amount of collagen increased 3.5-fold between Day 7 and 95 whereas total protein was relatively constant. When lung was exposed to smoke under in vitro conditions synthesis of collagen and non-collagen protein was almost completely depressed.

Papain-induced lung injury: Alterations in connective tissue metabolism without emphysema

The acute effects of the deposition of papain in the lungs of 4-month-old rabbits have been investigated with an amount not sufficient to cause emphysematous changes. During the first 2 days of in vivo deposition when hemorrhaging and inflammation occur, the total amounts of collagen and elastin in the lung, into which the papain had been instilled, did not change but the concentrations of collagen and elastin decreased 20 and 25% respectively. The rates of synthesis of collagen and other proteins doubled. By 4 weeks, collagen and elastin concentrations returned to, or were slightly above, control levels. The histological appearance and mean linear intercepts of lung sections and the compliance curves of excised lungs of the treated animals were similar to controls by 2 weeks after papain administration. The rabbit lung thus appears able to repair mild injury due to proteolytic enzymes.

Bleomycin-induced diffuse interstitial pulmonary fibrosis in baboons.

Pulmonary fibrosis was induced in eight baboons with bleomycin; five untreated animals were controls. After 45-65 U/kg of bleomycin, lung volumes and diffusing capacity were reduced, and static lung pressure-volume curves were shifted to the right. Right middle lobes were resected at this time in five bleomycin-treated and two control animals. Compared to controls, right middle lobes from bleomycintreated animals had increased weight and contained increased amounts of total protein, collagen, elastin, and DNA; synthesis of collagen and noncollagen protein were also elevated. Occasional alveolar septae were edematous and infiltrated by mononuclear inflammatory cells; a slight increase in collagen was demonstrable histologically. Four of six treated animals died with extensive diffuse interstitial fibrosis after 95 U/kg of bleomycin. Biochemical analyses revealed significantly elevated lobar contents of dry weight, protein, elastin, and collagen. Two animals survived 95 U/kg of bleomycin and were terminated 6 mo after treatment. In these animals, physiologic studies were indicative of restrictive lung disease, but lung histology was nearly normal. Lung weight, total protein, and DNA had returned to control values, but collagen and elastin were increased in amount and concentration. Bleomycin induces an intense inflammatory response in the lung. During this inflammation, connective tissue proliferation occurs in concert with proliferation of other tissue components. Cessation of bleomycin treatment is followed by resolution of inflammation manifested by decreases in tissue mass, cellular content, and nonconnective tissue protein. Collagen and elastin deposited during inflammation are less successfully removed during resolution, leading to a stage characterized by increased concentrations of these proteins. A similar sequence of tissue alterations may occur in idiopathic diffuse interstitial fibrosis of man in response to various lung injuries.

Glucocorticoid effects on vascular connective tissue during repair. Importance of dose level and pre- and post-injury treatment. Morphological and biochemical studies.

ABSTRACT Aorta of male albino rabbits were subjected to a single mechanical dilatation injury and the effects of different daily doses of prednisolone on the metabolism of collagen and glycosaminoglycans as well as on the content of alpha-amino nitrogen, RNA, DNA, water and fat and the histology of the descending thoracic aorta were analyzed 10 days after the injury. The effects of pre- and post-injury treatment with prednisolone were compared. Prednisolone inhibited the intimal thickening. This effect was enhanced by pre-injury treatment. Prednisolone also inhibited the biosynthesis of non-dialysable [14C]hydroxyproline-collagen, but increased the relative degradation of collagen in a dose dependent manner. The biosynthesis of glycosaminoglycans was decreased while prednisolone had no effect on the concentration and total amount of glycosaminoglycans, collagen, protein, RNA, DNA and fat. Finally the aortic content of water was decreased during treatment with prednisolone also in a dose dependent manner. It is concluded that the action of prednisolone on vascular collagen and water during repair is dose dependent and that the inhibitory action of prednisolone on the intimal thickening is enhanced by pre-injury treatment.

Intramuscular composition and texture of beef muscles

AbstractTotal collagen, heat soluble collagen, fat, moisture, sarcomere length and pH were determined on 18 muscles from two commercial beef animals. Each muscle was given a mild, moderate or severe cooking and the toughness determined using a mechanical compressive test. From the force‐deformation curve, measured throughout the test, three toughness values: the yield force, the final compressive force and the work done, were taken. In general, collagen content was associated with the compressive force and the other components with the yield force, although no precise distinction could be made. Collagen content, in particular the amount of total collagen, was the best predictor of toughness, but as the cooking became more severe, collagen accounted for progressively less of the variability in toughness. The other components contributed substantially to the variability in toughness only when meat was moderately cooked.

STUDIES ON THE LIVER ENLARGEMENT INDUCED BY DIETARY ADMINISTRATION OF DI-(2-ETHYLHEXYL) PHTHALATE (DEHP).

Di-(2-ethylhexyl) phthalate (DEHP) was mixed into diet and given to Wistar male rats for 16 days. A significant and dose-dependent increase in the relative liver weight (RLW) was observed in the rats fed DEHP at dietary levels greater than 0.1%. The RLW increased progressively with the duration of the treatment, reaching its maximun in two weeks. Biochemical analysis of the principal hepatic components has shown that the increase in RLW induced by DEHP was due to an increase in the total amounts of protein, water, lipid, and nucleic acids. The increase in protein was most marked and was due mainly to the increase in non-collagen protein. The total amounts of glycogen and collagen did not change. However, most of these components were found to be unchanged or reduced in their contents per liver weight, except that of protein. The increase in RLW is caused equally by the increase in cell number and in the cell volume, the nuclear DNA content being unaffected. The content of cytochrome P-450 in microsomes increased in the rats of both sex fed a 0.5% DEHP-diet for 16 days. However, the activities per mg of microsomal protein or per g of liver of aminopyrine N-demethylase and aniline hydroxylase decreased in male rats but increased in female rats. Total activities of these enzymes increased markedly in both sex of animals. Glucose 6-phosphatase, acid phosphatase and cytochrome c oxidase were reduced significantly in their activities per liver weight but glucose 6-phosphate dehydrogenase was unchanged. The significance of the liver enlargement induced by DEHP is discussed in relation to the physiological response of liver and to possible pathological changes of liver.

Heart volume and myocardial connective tissue during development and regression of thyroxine-induced cardiac hypertrophy in rats.

To determine whether development and regression of cardiac hypertrophy are accompanied by changes in heart volume and to learn whether a change in heart volume is associated with changes in the myocardial connective tissue, cardiac hypertrophy was induced in rats by administration of thyroxine. Rats were given L-thyroxine for 4 weeks. Heart volume was estimated radiologically in vivo at the start of the experiment and at 1- or 2-week intervals for 7 weeks. At each of these stages a number of rats were killed, their hearts were weighed and determinations were made of the myocardial contents of DNA, of collagen measured as hydroxyproline, and of glycosaminoglycans, measured as uronic acid. After thyroxine treatment the ratio of left heart ventricle weight to body weight and of heart volume to body weight rose significantly. The increase in heart weight was greater than the increase in heart volume. At the same time, there was a significant decrease in the concentration of hydroxyproline. After discontinuation of thyroxine treatment heart volume, heart weight and the concentration of myocardial collagen returned to normal within 2 weeks. However, the total amount of myocardial collagen was still less than normal at 2 weeks. The results suggest that the decrease in the amount of myocardial collagen associated with thyroxine-induced cardiac hypertrophy--because it results in a weakening of the supporting properties of the myocardial connective tissue framework--might contribute to a slight increase in in vivo heart volume.

The chemistry of human neonatal femoral epiphyseal cartilage

The estimation of cartilage constituents such as hydroxyproline and hexosamine may be used to detect gross changes in the total amount of collagen and matrix. This simple approach, which can only be regarded as a “screening” procedure prior to more exhaustive analysis, has been applied to samples of neonatal human cartilage. It is suggested that this method would be useful in analysing cartilage biopsies, especially from patients with bone dysplasias.

Collagen profile in rat granulation tissue after cyclophosphamide treatment.

Abstract: The collagen profile was studied in 2–3 week old granulation tissue, induced in rats by subcutaneous implantation of viscose cellulose sponges. Cyclophosphamide was given daily intraperitoneally, in a dose of 10 mg per kg during the entire experiment, beginning either 7 days before or on the day of the sponge implantation. Cyclophosphamide caused an increase in the water percentage, and decreased the dry weight and the total amount of collagen in the granulomas, reflecting a suppression of collagen synthesis. The catabolism of collagen was also inhibited in the cyclophosphamide treated rats, as indicated by a fall in the content of free OH‐proline and a lowering of the alpha/beta ratio in acid extracted collagen. Cyclophosphamide treatment increased the collagen solubility in acetic acid and increased the aldehyde content in relation to OH‐proline in purified collagen. This indicates that cyclophosphamide may inhibit the cross‐linking of collagen by blocking the aldehydes or decrease the stability of the collagen molecule by decreasing the hydroxylation of proline. Pretreatment with cyclophosphamide did not influence the effect of cyclophosphamide given during the development of granulation tissue.

GLUCOCORTICOID EFFECT ON REPAIR PROCESSES IN VASCULAR CONNECTIVE TISSUE

Male rabbits were injured by a single mechanical dilatation of the aorta and then injected with prednisone 2 mg/kg saline for 14 days or starved. Morphological studies and biochemical measurements of the collagen metabolism, the content of alpha-amino nitrogen, RNA, DNA, water and fat, and the aorta to serum ratio of 125I-albumin were performed on the intima-media layer of the descending thoracic aorta. Prednisone inhibited the intimal thickening. In the media the infiltration by mononuclear cells, the proliferation and regeneration of the smooth muscle cells and the calcification were reduced. Prednisone caused a decrease in 0.45 M NaCl soluble collagen as well as in the dialysable and non-dialysable 14C-hydroxyproline fractions. The total amount of collagen, elastin and alpha-amino nitrogen was unchanged, whereas the 14C-proline incorporation in the non-dialysable protein fraction was inhibited to a greater extent than the 14C-hydroxyproline synthesis. The findings indicate that prednisone inhibits the biosynthesis of collagen, which is inhibited to a greater extent than the general protein synthesis. Prednisone increased the dialysable to non-dialysable 14C-hydroxyproline ratio consistent with a relative increase in the catabolism of newly synthesized collagen. The aortic content of RNA and DNA was reduced consistent with the inhibition of protein synthesis and cell proliferation. Finally prednisone decreased the aortic content of water when related to the wet weight and increased the aortic content of fat. The aorta to serum ratio of 125I-albumin was not influenced by prednisone. It is concluded that administration of glucocorticoid for 14 days exerts an inhibitory action on the histological reaction to injury as well as on the biosynthesis of collagen of the repair processes in vascular connective tissue. A comparison with the effects of prednisone on undamaged rabbit aorta (Manthorpe et al. 1974) demonstrates that the metabolism of collagen of vascular connective tissue during repair is more sensitive to the antianabolic effects of prednisone than collagen in the non-injured aorta. Starvation caused an increase of the aortic percentage of water but otherwise had no influence on the repair processes in the vascular connective tissue.

The effects of cyclophosphamide and azathioprine on collagen in skin and granulation tissue in rats, and the effects of cyclophosphamide on collagen in human skin.

Granulation tissue was produced in rats by subcutaneous implantation of cellulose sponges. The effect of daily intraperitoneal injections of cyclophosphamide or azathioprine on rat skin and granulation tissue was examined after 14 and 42 days. Skin biopsies from patients with glomerulonephritis were analyzed before and after 42 days of treatment with cyclophosphamide or placebo. In the rats, cytostatic treatment caused an increase in the dry weight of the skin, and azathioprine increased the dry weight and the protein content of the granulomas. The increase in the dry weight was accompanied by a decrease in water percentage. The alpha-amino nitrogen/OH-proline ratio in purified acid soluble collagen from skin and granulation tissue increased with the dose and duration of cytostatic treatment. No effect on the aldehyde content was observed. Cyclophosphamide caused a decrease in the alpha/beta ratio in acid soluble collagen from granulation tissue, but not in the collagen from the skin. Salt soluble collagen was increased in the skin after 14 days of cytostatic treatment, but remained unchanged in the granulation tissue. In human skin cyclophosphamide caused no statistically significant changes in the amount of salt soluble or total collagen. It is concluded, that daily treatment of rats with cyclophosphamide or azathioprine from 14 to 42 days seems to inhibit the catabolic processes in the skin and granulation tissue, to decrease the hydroxylation of proline in collagen, and to inhibit the intermolecular cross-linking in collagen.?222

Partial purification and characterization of a lung antiproteinase and its differentiation from serum antiproteinases.

Model of Lung Growth. Unilateral pneumonectomy in the adult rabbit is followed by a compensatory doubling of the mass of the remaining lung within one month. This growth is accompanied by an increase in the total amount of collagen in the lung, yet the concentration of collagen per unit lung mass remains constant. This phenomenon is preceded by an apparent shift in the types of proteins synthesized by the growing lung, so that collagen synthesis is more pr~minent.~ Mechanisms of CoUagen Synthesis in Lung. A cellfree protein synthesizing system has been developed which actively synthesizes lung proteins including collagen. This technique has been used to demonstrate: (1) that collagen synthesis in lung takes place on large polysomes attached to the endoplasmic reticulum and (2) that the change in the relative rate of collagen synthesized in the developing neonatal lung is due, in part, to either a change in collagen gene expression or to a change in the number of cells synthesizing ~ollagen.~ Proteolysis of Collagen Synthesized in vitro. At least some of the collagen synthesized in vitro is lost following dialysis, suggesting that there must be mechanisms present in lung explant cultures to degrade collagen following synthesis. The relative amount of collagen hydrolyzed can be quantitated and the influence of serum proteins on this process can be investigated.