Changes of collagen and MMP-1 in liver, lung and kidney during growth of mice / 生物工程学报

The high performance liquid chromatography (HPLC) and enzyme-linked immunoassay (ELISA) were used to investigate the changes of collagen and matrix metalloproteinase-1 (MMP-1) in liver, lung and kidney during growth process of mice. The mice from 0 to 18 weeks were used as the research objects. The contents and proportions of hydroxyproline (Hyp), which were used to calculate the collagen contents, in liver, lung and kidney of different weeks were analyzed with HPLC. The contents and activity of MMP-1 in liver, lung and kidney of different weeks were analyzed with ELISA. The results showed that the collagen contents in liver, lung, and kidney were different (Lung(COL)>Kidney(COL)>Liver(COL)), and they all increased first and then decreased with weeks. The collagen contents in liver, lung, and kidney reached the highest level in the ninth (5.52 ng/mg), sixth (54.10 ng/mg) and ninth (19.20 ng/mg) week, respectively. Then it declined slowly from 9 to 18 weeks. The result of ELISA showed that the MMP-1 contents in liver, lung and kidney decreased first and then increased with weeks, and the trend of MMP-1 activity was opposite. It indicated that the increase of collagen contents in the tissues will inhibit the secretion of MMP-1.

Biochemical and Utralmicroscopic Evaluation of Myofibril Proteins and Collagen during Ageing in Broiler Chicken PSE (Pale, Sof, Exudative) Meat

Abstract The aim of this work was to study the myofibril proteins and collagen fraction changes in broiler chickens PSE (pale, soft, exudative) meat during ageing and their relationship to meat quality. The results presented an increase of myofibril proteins and collagen solubility promoted by the enhanced proteases activities during storage. Ultramicroscopically, the PSE meat samples revealed intracellularly a sarcomere super contraction and lacunas within the A and I bands while Z-lines appeared very dense and fragmented in comparison to normal samples. This observation was noticed already at 4h storage while extracellularly collagen fibrils decreased visually within the endomysium only after 24h of conditioning. These results influenced the quality as the PSE meat presented better functional properties at the first hours of conditioning before further proteins degradation by proteases. Thereafter, at the later ageing stage a further disintegration of the abnormal meat structure would affect the meat functional properties.

Passive Skeletal Muscle Excursion after Tendon Rupture Correlates with Increased Collagen Content in Muscle

PURPOSE: This study was designed to measure time-dependent changes in muscle excursion and collagen content after tenotomy, and to analyze the correlation between muscle excursion and collagen content in a rabbit model. MATERIALS AND METHODS: Twenty-four rabbits underwent tenotomy of the second extensor digitorum longus (EDL) muscles on the right legs and were randomly assigned to three groups based on the period of time after tenotomy (2, 4, and 6 weeks). The second EDL muscles on left legs were used as controls. At each time after tenotomy, passive muscle excursion and collagen content, determined by hydroxyproline content, were measured bilaterally, and the ratio of each value to the normal one was used. RESULTS: The mean ratio of muscle excursion after tenotomy to the value of the control decreased in a time-dependent fashion: 92.5% at 2 weeks, 78.6% at 4 weeks, and 55.1% at 6 weeks. The mean ratio of hydroxyproline content in muscle to the value of the control increased in a time-dependent fashion: 119.5% at 2 weeks, 157.3% at 4 weeks, and 166.6% at 6 weeks. There was a significant negative correlation between the ratio of hydroxyproline content in muscle after tenotomy to the control values and the ratio of muscle excursion after tenotomy to the control values (r=-0.602, p=0.002). CONCLUSION: The decrease in muscle excursion seems to correlate with the increase in collagen content in the muscle in a time-dependent fashion following tenotomy.

The Relevance of Degree of Liver Fibrosis, Ito cell, and PKC Activity in Hepatic Fibrogenesis / 대한간학회지

BACKGROUND/AIMS: Hepatic fibrosis in rat induced by thioacet amide shares similar morphological and biochemical characteristics with human liver cirrhosis. Thioacetamide (T AA) initially induces accumulation of collagen in Disse space and eventually leads to macro- and micronodular cirrhos is. Ito cell was believed to play a main role in hepatic fibrosis. And it s activity was known to be regulated by the expression of various genes. But little has been discovered about the upstream signal trans duction pathway of these genes in hepatic fibrosis. The expression of genesrelated to Ito cell activity was regulated by many transcription factors , the activity of which was regulated by protein kinase C( PKC) is oforms. So it is s upposed that PKC could be as s ociated with fibrosis in liver. METHODS: We investigated the correlation of PKC is oforms and It ocell activity in the course of hepatic fibrosis using TAA induced rat liver cirrhosis model. We used six week- old male rats , and administered 0.03% TAA in drinking water. The animals were sacrificed at 9, 20, and 30 weeks after TAA administration. The degree of hepatic fibrosis was evaluated by measuring the total amount of collagen.-SMA immunohist ochemical st aining of liver tissue was done to determine the Ito cell activity. The expression pattern of PKC isoforms was investigated by West ern blotting. RESULTS: In TAA- treated group, collagen cont ent and Ito cell activity did not increase until 30 weeks and 20 weeks of treatment , respectively, while in control group collagen cont ent and Ito cell activity were not detected. Collagen content showed linear correlation with Ito cell activity. This implied that the proliferation of activated Ito cells was prior to the increase of collagen content. In view of expression pattern of PKC is oforms, PKC alpha showed no difference in TAA- treated group and control group. In TAA-treated group, PKCbeta1 exhibited increased level of expression in both particulate and cytosolic forms at 9 weeks, while PKCdelta and PKC epsilon showed striking shift to particulated form. After 20 weeks, all of the PKC beta1, delta, and epsilon degenerated and showed remarkably decreased level of expression. This suggested PKC alpha had no relation to hepatic fibrosis,while PKC beta1, delta, and epsilon, showing activity at 9 weeks, were related to fibrosis og liver. In response to fibrogenic factors, molecules engaged in intracellular signal transduction pathway like PKC beta1, delta, and epsilon, began to change prior to the increase of Ito cell activity, morphologic changes and alterations of collagen content. CONCLUSION: Our results strongly suggest that the activity of PKC isoforms play an important role in early step of hepatic fibrosis, while accompanying Ito cell activity do in later step.

Effects of exercise training on back skin and achilles tendon collagen content in growing mice / 体力科学

Male mice of dd-strain, at 3 weeks of age were used at the start of the exercise training. The exercise training continued successively throughout the 3 to 7 weeks of age. The trained group was divided groups ; namely, light-, middle- and heavy-trained groups, which were exercised on a treadmill. The treadmill exercise program for light-, middle- and heavy-trained groups consisted of running at speeds of 6 m/min, 10 m/min and running up a 10% grade at a speed of 12 m/min for 10 min 5 times a week, respectively. The untrained group was used as control under normal laboratory condition. The skin and Achilles tendon of the four groups were sampled and their collagen content were examined by means of concentration of hydroxyproline. The collagen content in the skin of growing mice did not recognize significant difference among the four groups. On the other hand, the collagen content in the Achilles tendon of growing mice clearly recognized significant difference between the middle-trained and untrained groups and/or between the middle-trained and light-trained groups. However, middle-exercise training reduced the accumulation of collagen in the Achilles tendon of grow. ing mice.

Effects of physical activity on collagen content in mice / 体力科学

Male mice of dd-strain, at 4 and 8 week-ages were used at the start of the trained. The trained continued for successive during 4 to 34 week-ages and 8 to 70 week-ages. The trained group was exercised on a treadmill, and the untrained group used as control under normal laboratry condition. The skin of the right dorsum near the tail was sampled and its collagen content was examined by means of concentration of hydroxyproline. The collagen content in the skin of the trained group is lower than in that of the untrained one at each week-age, 14-18, 27-34 and 63-70 week-ages. The trained group was depressed hydroxyproline concentration of defatted skin, compared with untrained one at each weekage. The continuous exercise reduced the accumulation of collagen in the skin of mice.