Autoradiographic studies in experimental lathyrism

Abstract

PLATES XXIX-XXXIII) THE lesions of experimental lathyrism are striking, but it is not known how they are produced. There is evidence that a ground-substance change may be responsible (Menzies and Mills, 1957 ; Ham, 1960) and other observations have suggested an alteration in collagen (Hurley and Ham, 1959 ; Levene and Gross, 1959). In the present work, the specificity of labelling of sulphated mucopolysaccharides in vivo with sulphur-36 given as sulphate (Curran and Kennedy, 1955) has made it possible to determine the distribution of these sulphated compounds by autoradiography, and their relation to lathyric lesions. In a similar way protein metabolism in the lesions has been investigated with sulphur-35 methionine and carbon-14 glycine as precursors. The effect of lathyrogenic agents on the distribution of 36S-sulphate-labelled compounds in healing fractures has also been investigated. The results sustain the hypothesis that the essential change in lathyrism is a failure of formation of chondroitin sulphate A and C complexes with protein, and a subsequent defect in fibrogenesis. MATERIALS AND METHODSA sweet-pea diet, p-amino-propionitrile (BA.E") and amino-acetonitrile ( M ) were used to produce experimental lathyriem in 52 Wistar rats. The animals were 4-7 weeks old a t the beginning of the experiment. Both sexes were used. Cyrrtamine, reported as lathyrogenic (Dasler and Milliser, 1958). was given to 12 weanling rats. Animals suffering from lathyrism are here called lathyric animals.Swest pea (Geiger st al., 1933 ; Ponseti and Baird, 1952). The diet consisted of Lathyma odoratua peas and pellets of standard rat diet crushed together in equal parts by weight. It was given to 11 rats for 3 mth to 1 yr. One of the animals waa given daily subcutaneous injections of BAPN (Wawzonek et al., 1955) so that it received a total of 30 mg. over 15 days, and another received 80 mg. given similarly over 20 days, before injection of isotope.A A N (Wawzonek et al., 1955). This compound waa given daily in 1 6 2 0 mg. doses in water, orally or subcutaneously, to 41 rats. T h e total dose per animal ranged from 60 to 550 mg. Five of these animals received daily 1 mg. deoxycorticosterone acetate (DOCA) subcutaneously (Selye and Bois, 1957). The total dose of DOCA per animal ranged from 15 to 55 mg. and the corresponding AAN range was 250-550 mg. Cyata?nine (Daaler and Milliser, 1958). Cystamine dihydrochloride waa given daily in 10-40 mg. doses in water orally to 12 rats. The total dose per animal ranged from 240 to 1050 mg.

Changes in permeability of articular cartilage in experimental lathyrism.

“…The decrease in permeability found in this study parallels that found in papain-treated animals where the apparent degradation of the protein moiety of proteinpolysaccharide complex takes place (Thomas, 1956). This finding of decreased permeability suggests a defect in lathyrism of complex formation between non-collagenous protein and mucopolysaccharides as reported by Kennedy and Kennedy (1962). Since chondroitin sulphate-protein macromolecules exhibit a surface attachment to collagen fibres (Serafine-Fracassini and Smith, 1966), and this * : : õ 4 ' .…”

Experimental Lathyrism: Apparent Antithesis of Aging in Connective Tissue

“…Kennedy and Kennedy (72) found no evidence of the inhibition of cellular utilization of sulfate nor any significant abnormal accumulation of labelled sulfated mucopolysaccharide in the epiphyseal lesions examined. They described an absence of activity in the abnormal‐appearing fibrillar matrix, but relatively normal sulfate distribution where the matrix appeared normal by histologic examination.…”

“…The rents and tears which subsequently develop and progress to a slipping of the epiphysis, begin at these zones of negative metachromasia. Kennedy and Kennedy (72) also investigated utilization of sulfate by means of the fracture callus in normal and lathyritic animals and again found no significant difference from the normal in areas where the matrix appeared normal, but a lack of sulfate in altered, fibrillar matrix. One very interesting observation reported by them is the fact that the epiphyseal plates of the fractured bones of lathyritic animals failed to show the deranged pattern of sulfate utilization seen in their stress‐bearing counterparts.…”

“…Since sulfated polysaccharides have been implicated in the formation and stabilization of the collagen fibril, it would seem possible that they are also involved in the pathogenesis of experimental lathyrism. Several investigations have been reported in which attempts were made to define the effects of lathyrogen treatment on sulfate metabolism in the intact animal (5, 49, 63, 70‐80), in primarily explanted tissue (63, 81) or in established tissue‐culture cell lines (82). The results have been somewhat inconclusive.…”

Changes of Glycosaminoglycan Sulphation in the Cornea of Lathyric Chick Embryos

“…Decreased sulphation activity due to action of lathyrogens has been de monstrated as one of the principal molecular syndroms taking place in the lathyric connective tissue [Kennedy and Kennedy, 1962]. Deep inhibition of radioactive sulphate incorporation into glycosaminoglycans of the connective tissue in lathyric rats was described following the administration of various lathyrogens [Shintani and Taylor, 1962; Karnovsky and Karnovsky, 1961].…”