Degeneration Of Chondrocytes Research Articles

Slipped Capital Femoral Epiphysis

Twenty-three core biopsy specimens from patients with slipped capital femoral epiphysis and 11 control growth plates were studied by electron microscopy. Block staining with toluidine blue for demonstration of proteoglycans at the ultrastructural level was also used. The proliferative and hypertrophic zones of slipped growth plates showed diminished cellularity and marked distortion of the architecture with disarray of the cartilage columns. There was a deficiency and abnormality in the supporting collagenous framework of slipped plates. Chondrocyte degeneration and death were seen at all levels of the proliferative and hypertrophic zones, suggesting a disturbance in the life cycle of chondrocytes. The significance of these findings and their relationship to mechanistic, endocrine, and other proposed etiologies of epiphyseal slipping is discussed.

Type II collagen-induced arthritis. A morphologic and biochemical study of articular cartilage.

Articular cartilage was obtained from type II collagen-induced arthritic rat joints. Transmission electron microscopy showed a gradual degeneration of chondrocytes, disorganization of the collagenous extracellular matrix, and formation of microscars. Biochemical analyses indicated that type II collagen was the only collagen present and that it was normal in regard to hydroxylation of lysine and glycosylation of hydroxylysine. Analyses of the proteoglycan in the extracellular matrix revealed a 50% loss of chondroitin sulfate and keratan sulfate.

Immunohistochemistry of types I and II collagen in undecalcified skeletal tissues.

Types I and II collagen were demonstrated in semithin sections of undecalcified human endochondral growth plate, articular cartilage, and subchondral bone. The effects of several different methods for fixation, embedding, exposing of antigenic determinants, and immunoperoxidase staining were examined. Fixation in buffered formalin and paraformaldehyde-lysine-periodate solution gave more intense staining for collagens than fixation in paraformaldehyde-gluaraldehyde or Bouin's solution. Specimens embedded in Spurr epoxy resin yielded intense and uniform staining of areas known to contain the particular collagens after the resin had been removed by sodium ethoxide. The staining was enchanced following enzymatic digestion, especially with protease V (Sigma). Staining sensitivity and specificity were comparable with the indirect conjugate and double peroxidase-antiperoxidase (PAP) techniques; the PAP method was less sensitive. Embedment in methacrylate resins proved unsatisfactory because of exaggerated immunostaining of mineralized sites in comparison to unmineralized areas of the same tissues. In the growth plate specimens, type I collagen was identified in the matrices of bone, periosteum, perichondrium, and in the cytoplasm of hypertrophic and degenerative chondrocytes. Type II collagen was found uniformly throughout the cartilage matrix and in spicules of unresorbed cartilage matrix located in subchondral bone. A similar staining pattern was observed for the articular cartilage, except that type I collagen was not detected in chondrocytes.

Studies on Bone Formation by Cartilage Reconstructed by Isolated Epiphyseal Chondrocytes, Transplanted Syngeneically or across Known Histocompatibility Barriers in Mice

Calcified cartilage transplants induce bone formation. This process may be inhibited if the recipient is immunized by the transplant. To study the relation between the degree of antigen incompatibility between the donor and recipient and bone formation in more detail, chondrocytes isolated from cartilaginous epiphyses of five-day-old mice were transplanted within a fully compatible syngeneic system and across weak (H-Y, non-H-2) and strong (H-2) histocompatibility barriers. Reconstruction of cartilage occurred in all cases. In these transplants, which did not evoke immunologic reaction (fully compatible system, transplants across H-Y barrier in nonrejector strain), reconstructed cartilage hypertrophied, calcified, yielded to resorption by mesenchyme, and finally, was replaced by bone. When (independently of the degree of antigenic difference) cartilage was surrounded by mononuclear infiltration, bone formation did not occur or was delayed. The presence of infiltrations around transplants led to the degeneration of chondrocytes as well as of matrix in peripheral regions of cartilage. Immunologic infiltration may prevent endochondral osteogenesis by inhibiting cartilage invasion by vascularized mesenchyme, and/or interfering with matrix mineralization. The function of the chondrocyte is not yet defined, but in endochondral ossification, it plays more than a passive role.

Experimental study of the effects of steroids (MPS and MPA) frequently applied into the knee joint on the articular cartilage

Recently various steroids have been used focal or systemic in rheumatoid arthritis, osteoarthritis and allergic or other collagenic diseases. In this study, we have investigated the histopathological effects of MPA long term-affected and MPS short term affected on the articular cartilage of the knee joint of 32 adult New Zeland. According to the steroids that we have used, were observed weight loss, marked osteoporosis in the surroundings of the knee joint. Grossly sparced dark yellow areas of the articular cartilage, microscopycally the thinning of the cartilage, the diminish in number, degeneration and necrosis of chondrocytes, the formation of the cyst and the microcyst within the matrix, the production of the fibrous tissue around the cyst, the thinning of the subchondral trabeculae. The pathological change in the right knee joint after being given steroids were found more evident than those in the left knee ioint injected salin. It has been seen that these pathological changes have significantiy increased progressively as related to the period. The dosage and the frequency of the steroids. It has also noticed that these lesions have significantiy produced in the left knee joint iniected salin as related to the period and the dosage of steroids. The lesions thot MPS has caused were more less than those of MPA and they were equally in each two knee joint. Consequently we have determined experimentaliy that the given steroidsiocal intra-articular or systemic, have resulted in the progressively increasing death and degeneration of the chondrocytes, the formation of the cyst and the microcyst within the matrix, the production of the fibrous tissue around the cyst and the thinning of the cartilage and the subchondral trabeculae as reiated to the period, the dosage and the frequency of the steroids.

An ultrastructural study on the ear cartilage of rabbits after the administration of papain. Appearance of cross-striated collagen segments of an atypical FLS-type.

Crude papain was administered intravenously to young rabbits and the cartilage of the collapsed ear was examined electron-microscopically. Degeneration and recovery of chondrocytes, and decrease in and recovery of the electron-density of elastic fibers, were observed during the collapse and restoration of the ear. Some samples were stained with ruthenium red. In the collapsed ear, with a marked decrease of proteoglycan in the cartilage, loss of ruthenium red-positive granules was observed in the extracellular matrix. Collagen fibrils in the cartilage appeared to be somewhat increased in number, some of their diameters became slightly greater, and a part were assembled into bundles, occasionally accompanied by periodic cross-striation. Decrease of proteoglycan in the cartilage matrix probably brought about the unmasking and the assembly of collagen fibrils. In one of the experimental animals, collagen fibrous segments of an atypical fibrous long spacing (FLS-)type with symmetrical cross-striation were found around the chondrocytes in the ear cartilage, during the period of recovery. Some kind of the endogenous sulfated carbohydrate may have acted to affect the arrangement of type II collagen or procollagen molecules newly produced by the recovering chondrocytes.

Resorption of uncalcified cartilage in the diaphysis of the chick embryo tibia

The resorption of the uncalcified cartilage matrix of the middle third of the diaphysis in the chick embryo tibia has been studied using histological, histochemical and electron microscopic techniques. The first stage in the resorption process affects the periosteal bone, which is breached by osteoclasts at one or several points. Capillary vessels and clear, apparently undifferentiated cells penetrate through the holes so formed and reach the cartilage. The loss of acid proteoglycans to a depth of 10--20 micrometer into the matrix is the first sign of cartilage resorption; it is followed by the digestion of collagen fibrils, the opening of cell lacunae, chondrocyte degeneration and fragmentation and, lastly, the complete dissolution of the cartilage. This process is mediated by cells which probably derive from perivascular elements. Most of these cells have an undifferentiated appearance, but they have macrophagic properties, as is shown by phagocytotic activity along their plasma membrane, by the presence of lysosome-like bodies in their cytoplasm, and by their intense acid phosphatase activity. Resorption by giant cells of chondroclastic type only occurs at a late stage.

Two types of heritable lethal achondrogenesis

Examples of two types of perinatal lethal achondrogenesis are described. Review of the cases previouslyreported in the literature confirms the existence of two clearly distinguishable subtypes. Fraccaro-Houston-Harris type (type 1) is characterized by poor ossification of calvarium, multiple rib fractures, very short, broad bones of the extremities with marked bowing, and severe retardation of chondrocytic proliferation in the physeal cartilage. Langer-Saldino type (type II) is characterized by normal ossification of calvarium, absence of rib fractures, diaphyseal constriction of long bones in the extremities, and degeneration of chondrocytes, especially in the physeal growth zone. It is postulated that the primary disorder in type 1 resides probably in connective tissue, whereas type II is a degeneration of proliferating epiphyseal and physeal cartilage.

Enhanced mineralization of the tibial epiphyseal plate in the rat following propylthiouracil treatment: a histochemical, light, and electron microscopic study.

AbstractFollowing treatment with propylthiouracil, most chondrocytes in the reserve and upper proliferation zones in the tibial epiphyseal plate exhibit degenerate ultrastructural morphology. In the extracellular matrix, sulfated mucopolysaccharide is reduced, matrix vesicles are increased both in number and in size, apatite crystals are present in all zones, and mineralization is enhanced.In post‐treatment recovery, chondrocyte degeneration decreases; however, the extracellular matrix is considerably delayed in returning to conditions comparable to those in corresponding controls and this is indicated by the continued presence of apatite crystals in abnormal locations.Chondrocyte degeneration, sulfated mucopolysaccharide, and matrix vesicles, are discussed as they relate to the mineralization process.

Relapsing polychondritis--report of a case with ultrastructural findings of the ear cartilage.

A case of relapsing polychondritis in a 48‐year‐old female is reported. In a biopsy specimen of the auricular cartilage, inflammatory cell infiltration with plasma cells, lymphocytes and neutrophils, wandering of macrophages, fibroblasts and invasion of capillaries were found. The matrix showed loss of basophilia and markedly decreased reactivity with alcian blue staining. This decreased reactivity corresponds with decrease of small granules containing acid mucopolysaccharide ultrastructurally. The main pathologic change of relapsing polychondritis is the decrease of small granules in cartilage matrix, followed by inflammatory reaction, and degeneration of chondrocytes. The reason for the decrease in number of the small granules is still not clear, but an immune mechanism might be contributable.

Further evidence for the vitality of chondrocytes in the mandibular condyle as revealed by 35 S-sulfate autoradiography.

AbstractHistochemical and autoradiographic studies using 35S‐sulfate indicate that the majority of the cartilage cells in the developing mandibular condyle of the young mouse are active, vital cells. Concomitant with the increase of hypoxic conditions within the deeper layers of the cartilage, an increase in sulfated glycosaminoglucuronoglycans synthesis takes place. Hypertrophic chon‐drocytes in the premineralized and mineralized zones reveal marked 35S‐sulfate uptake in comparison with the less differentiated cells in the chondroblastic and perichondrial zones. These observations of radiosulfate activity support the concept that calcification processes in the condylar cartilage are not necessarily accompanied by degeneration and death of the hypertrophic chondrocytes. The radiosulfate activity of the surviving chondrocytes in the vicinity of the ossification front indicates possible modulation into osteoprogenitor cells.

Ultrastructural effects of estrogen on epiphyseal cartilage.

Ten male weanling Holtzman rats, injected intraperitoneally with aqueous estradiol (Progynon, Schering), in daily doses of 1 μg. per g body weight, were sacrificed, simultaneously with controls receiving an equivalent amount of diluent, at intervals ranging from one hour to six days. Upper tibial epiphyseal cartilage plates (ECP), procesed for electron microscopy, revealed, as early as three hours after injection, appreciable enhancement of secretory activity, evidenced, in the zone of matrix secretion, by the abundance in Golgi cisternae of stippled material representing proteinpolysaccharide complexes. Disintegration of the lining membrane of individual Golgi vesicles was advanced after twenty-four hours; following three days of treatment, few vesicles remained intact, and pools of initially intravacuolar material were observable in the gound plasm. Long filaments, suggestive of primary or precursor collagen fibrils were apparent in this secretion. After six days, virtual lakes of this substance filled cells in the zone of prehypertophy, with consequent displacement of the rough endoplasmic reticulum against the cell periphery. Cytoplasmic vacuoles, containing mateerial similar to that found in the lacunar moat, and displaying finely beaded, radially arrayed filaments on the lining membrane were frequently encountered. Our observations suggest an initial acclleration of chondrocytic secretory activity, with subsequent retardation of transport. The resultant retention and intracellular polymerization of precollagenous products accelerates hypertrophy, thereby promoting early degeneration of chondrocytes. These ultrastructural alterations are apparently estrogen-specific.

PHOSPHATASES OF EPIPHYSEAL CARTILAGE STUDIED BY ELECTRON MICROSCOPIC CYTOCHEMICAL METHODS

The presence and distribution of alkaline phosphatase, adenosine triphosphatase (ATPase) and acid phosphatase activities in the epiphyseal plates of young mice were studied by electron microscopic cytochemical methods. Alkaline phosphatase and ATPase activities were associated with the plasma membranes of chondrocytes and with the investing membranes of matrix vesicles. These vesicles contain the earliest recognized deposits of hydroxyapatite and may promote calcification through an active process. Alkaline phosphatase and ATPase activities were greatest in the hypertrophic zone of the epiphysis, which is an area of beginning calcification. Acid phosphatase activity was demonstrable in the cytoplasm of chondrocytes in association with dense bodies which were larger than matrix vesicles and were devoid of alkaline phosphatase and ATPase activities. These cytoplasmic lysosome-like bodies were slightly more numerous in the hypertrophic zone but disappeared in the underlying zone of chondrocyte degeneration and matrix calcification. Our observations do not support a previous suggestion by others that matrix vesicles represent lysosomes. The presence of ATPase and alkaline phosphatase is compatible with an enzymatic calcium- and/or phosphate-concentrating mechanism in the matrix vesicles.

Stimulation of articular cartilage of young adult mice by hormones.

Young adult male mice of strain C<sub>δ</sub><sub>7</sub>Bl were treated with somatotrophin, thyroxine or estradiol benzoate and were observed for 24 h, 2, 4 days or 1 or 2 weeks. The articular cartilage of the femoral head reacted to the treatment with ultra-structural changes in cells and matrix. Chondrocytes were relatively less and the matrix was relatively more conspicuously altered than in growing mice treated similarly. The changes observed are consistent with accelerated passage of cell products into the matrix and with altered cellular activity in regard to the production of components of the matrix. Early effects were followed by intensified degeneration and death of chondrocytes.

Articular and internal remodeling in the human otic capsule.

AbstractA comprehensive histologic study of the human otic capsule is presented demonstrating the interrelations between cartilage, bone, blood vessels and soft tissue throughout life. Remodeling occurs through continual degeneration of chondrocytes within the uncalcified articular surfaces of the stapediovestibular joint and through continual degeneration of cartilage about the cochlea and semicircular canals. Degenerated chondrocytes are removed by macrophages and new endochondral bone forms from adjacent osteogenically active blood vessels. The cartilage surfaces of the footplate and oval window are constantly replenished by new cartilage formed by mesenchymal cells of the annular ligament. Within the otic capsule, new cartilage forms from mesenchymal cells lining the labyrinth. Cartilage foci continually undergo partial replacement by endochondral bone with remnants of uncalcified cartilage matrix remaining, forming globuli ossei and interglobular spaces. In addition to continual endochondral bone formation partially replacing the continually forming and degenerating cartilage, chondroid bone forms by direct transformation of some cartilage to bone. These chondroid bone areas are cellular in young age groups, but become pale and relatively acellular with age. These processes occur throughout life, regardless of age or sex.

Extreme retardation of epiphyseal growth from roentgen irradiation; a case study.

Extreme variation in leg length is both disabling and distressing. Seldom does one encounter this situation as the result of x-irradiation. The inhibiting and destructive effects of roentgen rays on epiphyseal cartilage have been demonstrated in the animal by a number of investigators. During the first decade of the twentieth century Perthes, Recamier and Tribondeau, Forsterling and Krukenberg subjected numerous small animals to irradiation, demonstrating that exposure to x-rays caused more or less retardation in the growth of bones and other structures. In general, it was determined by these investigators that the degree and duration of growth inhibition were governed by the age of the animal and the dosage. In late years, detailed animal studies, well controlled, have been conducted by Barr and his associates (1, 7), Bisgard and Hunt (2), Brooks and Hillstrom (3), Regen and Wilkins (6). Their observations demonstrate without question that bone growth in the young can be retarded or stopped by a sufficient dosage of x-ray. The microscopic picture of the epiphysis following irradiation is that of chondrocyte degeneration — diminished numbers of primitive chondrocytes, a disruption of the orderly arrangement of cartilage columns and abnormal foci of calcification away from the normal metaphyseal location. No significant evidence of growth stimulation has been observed, and the picture of cartilage regeneration has been inconsequential. Barr and Bisgard and Hunt have called attention to the insults to the hemopoietic system in the metaphyses as revealed by the fibrous character of the marrow space. Careful measurements of long bones following exposure reveal not only less length than normal but decrease in shaft diameter and cortical thickness. The changes noted in hyaline joint cartilage are apparently insignificant from a clinical standpoint. The literature does not divulge a large number of cases in which longitudinal growth was followed after therapeutic irradiation about the epiphyses. Desjardins (4) reported the case of a nine-year old girl irradiated for a tumor of the upper humerus. The total dosage was not recorded. Five years following treatment there was marked shortening of the humerus with atrophy of the shoulder musculature. Stevens (9) over a period of two months gave a four-month-old child 1,816 r for a nevocarcinoma of the left thigh, lower abdomen, and vulva. The tumor was successfully controlled, but at the age of four years the left limb measured two inches shorter than the right. In the face of this retarded growth, Stevens urged great care in irradiating infants. Judy (5), in a preliminary report, described changes effected in three children submitted to irradiation in an attempt to correct asymmetry in the length of the lower extremities. The ages were five to eight years, and the discrepancy between the two limbs 1¼ to 3 inches.