Spontaneous hyaline cartilage regeneration can be induced in an osteochondral defect created in the femoral condyle using a novel double-network hydrogel

<p>Abstract</p> <p>Background</p> <p>Functional repair of articular osteochondral defects remains a major challenge not only in the field of knee surgery but also in tissue regeneration medicine. The purpose is to clarify whether the spontaneous hyaline cartilage regeneration can be induced in a large osteochondral defect created in the femoral condyle by means of implanting a novel double-network (DN) gel at the bottom of the defect.</p> <p>Methods</p> <p>Twenty-five mature rabbits were used in this study. In the bilateral knees of each animal, we created an osteochondral defect having a diameter of 2.4-mm in the medial condyle. Then, in 21 rabbits, we implanted a DN gel plug into a right knee defect so that a vacant space of 1.5-mm depth (in Group I), 2.5-mm depth (in Group II), or 3.5-mm depth (in Group III) was left. In the left knee, we did not apply any treatment to the defect to obtain the control data. All the rabbits were sacrificed at 4 weeks, and the gross and histological evaluations were performed. The remaining 4 rabbits underwent the same treatment as used in Group II, and real-time PCR analysis was performed at 4 weeks.</p> <p>Results</p> <p>The defect in Group II was filled with a sufficient volume of the hyaline cartilage tissue rich in proteoglycan and type-2 collagen. The Wayne's gross appearance and histology scores showed that Group II was significantly greater than Group I, III, and Control (p < 0.012). The relative expression level of type-2 collagen, aggrecan, and SOX9 mRNAs was significantly greater in Group II than in the control group (p < 0.023).</p> <p>Conclusions</p> <p>This study demonstrated that spontaneous hyaline cartilage regeneration can be induced <it>in vivo </it>in an osteochondral defect created in the femoral condyle by means of implanting the DN gel plug at the bottom of the defect so that an approximately 2-mm deep vacant space was intentionally left in the defect. This fact has prompted us to propose an innovative strategy without cell culture to repair osteochondral lesions in the femoral condyle.</p

Development of a time-resolved fluoroimmunoassay for salmon insulin-like growth factor binding protein-1b

In salmon plasma/serum, three major insulin-like growth factor binding proteins (IGFBPs) are consistently detected at 22-, 28- and 41-kDa. The 22-kDa form has been identified as IGFBP-1b and shown to increase under catabolic conditions. We developed a competitive time-resolved fluoroimmunoassay (TR-FIA) for salmon IGFBP-1b. Purified salmon IGFBP-1b was used for biotin-labeling, assay standard and antiserum production. The TR-FIA did not cross-react with the 41-kDa form (IGFBP-2b) but showed 3% cross-reactivity with the 28-kDa form (IGFBP-1a). It measured IGFBP-1b levels as low as 0.4 ng/ml, and ED80 and ED20 were 0.9 and 24.6 ng/ml, respectively. There appears to be little interference by IGF-I. Using the TR-FIA, serum IGFBP-1b levels were measured in individually-tagged underyearling masu salmon fed or fasted for 5 weeks, or fasted for 3 weeks followed by refeeding for 2 weeks. Fasting for 3 weeks significantly increased circulating IGFBP-1b levels, while it returned to the basal levels after prolonged fasting for additional 2 weeks. Serum IGFBP-1b level negatively correlated with body weight, condition factor, specific growth rate and serum IGF-I level. During parr-smolt transformation of masu salmon, average circulating IGFBP-1b levels were the highest in May. There was a positive correlation between serum IGFBP-1b and IGF-I, which is in contrast to that in the fasting/feeding experiment. IGFBP-1b also showed a positive relationship with gill Na+, K+-ATPase activity. These results suggest that the relationship between circulating IGFBP-1b and IGF-I during smoltification differs from that during fasting and IGFBP-1b may play a role in the development of hypoosmoregulatory ability. (C) 2015 Elsevier Inc. All rights reserved

Age and body size of Japanese eels, Anguilla japonica, at the silver-stage in the Hamana Lake system, Japan

Effects of salinity-different habitats on growth rate, age and body size of Japanese eels at the silver-stage were investigated. Fish were sampled in one drainage system, that includes the brackish Hamana Lake and its inlet freshwater rivers, and were evaluated using otolith strontium:calcium (Sr : Ca) analysis to determine whether the eels had been living in estuarine or freshwater habitats. The growth rate of estuarine eels was found to be significantly higher than that of river eels for both females and males. In male silver eels, there was no difference in age between estuarine and river eels, but the total length and body mass (BM) of estuarine eels were significantly larger than river eels. In female silver eels, the age of river eels was significantly older than those of estuarine eels and the BM of river eels was significantly greater than in estuarine eels. These results indicate that effects of habitat use and salinity differences on age and body size at the silver-stage were different between female and male eels in this system

Age and body size of Japanese eels, Anguilla japonica, at the silver-stage in the Hamana Lake system, Japan

Effects of salinity-different habitats on growth rate, age and body size of Japanese eels at the silver-stage were investigated. Fish were sampled in one drainage system, that includes the brackish Hamana Lake and its inlet freshwater rivers, and were evaluated using otolith strontium:calcium (Sr : Ca) analysis to determine whether the eels had been living in estuarine or freshwater habitats. The growth rate of estuarine eels was found to be significantly higher than that of river eels for both females and males. In male silver eels, there was no difference in age between estuarine and river eels, but the total length and body mass (BM) of estuarine eels were significantly larger than river eels. In female silver eels, the age of river eels was significantly older than those of estuarine eels and the BM of river eels was significantly greater than in estuarine eels. These results indicate that effects of habitat use and salinity differences on age and body size at the silver-stage were different between female and male eels in this system

Responses of insulin-like growth factor (IGF)-I and two IGF-binding protein-1 subtypes to fasting and re-feeding, and their relationships with individual growth rates in yearling masu salmon (Oncorhynchus masou)

Two subtypes of insulin-like growth factor binding protein (IGFBP)-1 are present in salmon blood and they are both up-regulated under catabolic conditions such as stress. The present study examined effects of fasting and re-feeding on IGFBP-1a (28-kDa form) and IGFBP-1b (22-kDa form) both at mRNA and protein levels along with IGF-I and RNA/DNA ratio in yearling masu salmon. Fish were individually tagged and assigned to one of three treatments: Fed, Fasted or Re-fed. Circulating IGF-I levels significantly decreased after fasting for 5 weeks and were positively correlated with individual growth rates. Liver igf-1 mRNA levels were not affected by the treatment. Muscle RNA/DNA ratio did not respond to fasting nor showed correlations with growth rates. Circulating IGFBP-1a and IGFBP-1b increased during fasting and decreased after re-feeding. Both serum levels were inversely correlated with growth rates, while IGFBP-1b had consistent negative relationships with growth rates. Fasting/re-feeding also affected their mRNA levels in the liver. These results suggest that circulating IGF-I and IGFBP-1b could serve as positive and negative indices of growth, respectively, in masu salmon. Different sensitivities of IGBP-1a and IGFBP-1b may be useful to assess a broad range of catabolic conditions when they are combined

Morphological changes and otolith growth during metamorphosis of Japanese eel leptocephali in captivity

To know the morphological changes in body shape and otolith growth during metamorphosis of anguillid eel larvae, we observed the process of metamorphosis in artificially reared leptocephali of the Japanese eel Anguilla japonica that were reared at four different temperatures, 15, 20, 25 and 30℃ for 30 days. After the onset of metamorphosis, total length and relative preanal length decreased following the progress of metamorphosis. Relative body depth showed almost constant values at the early metamorphosis stage, but showed a rapid decrease at the late metamorphosis stage. Survival of the 11 leptocephali of each experimental group held at four different temperatures showed the highest rate of 81.8% at 25℃. Similarly, the number of leptocephali that completed metamorphosis to be glass eels was greatest at 25℃ (5 specimens), suggesting that the temperature of 25℃ facilitated the metamorphosis and survival of leptocephali. Otoliths drastically grew fast after the initiation of metamorphosis and deposited a mean width of 47.0μm during the 30 days of the experimental period, while otoliths of non-metamorphosed leptocephali showed only a slight mean increase of 11.2μm during the same one-month period. These results are the first demonstration of morphological change and otolith deposition during the metamorphosis process in anguillid eels

Discriminant analysis of age to enable rapid estimation of 0-age Japanese eels Anguilla japonica

Anguillid eels are declining worldwide, so monitoring of their annual recruitment is important, but labor-intensive. Efficient ways to assess the abundance of their new recruits (0-age) each year would therefore be useful. Three discriminant analysis methods were evaluated for their ability to identify 0-age eels based on the total length (TL) of eels that included various age classes from 0-age to ≥2-age. Japanese eels were sampled every month from 2007 to 2009 in the Imagawa River, an inlet river of Hamana Lake in Japan, and the ages of 223 eels (50 to 250 mm TL) were determined using otolith annuli analyses. All three discriminant analyses could predict 0-age eels more accurately than 1-age and ≥2-age eels based on TL and catch date data. Canonical discriminant analysis appeared to be best for predicting 0-age eels, with all eels determined by otolith analysis as 0-age being correctly predicted (100%) in the leave-one-out cross validation method, although 2.4% of 1-age eels were wrongly predicted as 0-age. Studies of the recruitment patterns, habitat use, or ecology of 0-age recruits in a river system would be possible without additional aging efforts after a discriminant analysis function was created for a river system