PARTIAL CHARACTERIZATION OF OVINE SKELETAL-MUSCLE PROTEOGLYCANS AND COLLAGEN

Ovine longissimus dorsi and biceps femoris muscles were analyzed for p roteoglycan content, collagen and lysine aldehyde-derived collagen cro sslinking concentrations at 2-4 days, six-month-old, and six-year-old stages of development. Tissue extracted proteoglycan molecular sieve d istribution on a Sephacryl S-200HR column revealed two proteoglycan po pulations with estimated relative molecular weight ranges of 200,000 t o 250,000 daltons and 23,000 to 70,000 daltons. The molecular sieve di stribution was similar between the two muscles within a developmental age, but changed as a function of developmental age. Primary culture f rom both the longissimus dorsi and biceps femoris muscle liberated pro teoglycans into the culture medium. In contrast to the tissue extracte d proteoglycans, at the six-year-old stage of development, culture med ium liberated proteoglycan Sephacryl S-200HR molecular sieve distribut ion differed between the two muscles. In both the tissue extracted and medium liberated proteoglycans at all developmental stages, nitrous a cid deamination demonstrated the presence of heparan sulfate. Immunobl ot analysis of the tissue extracted proteoglycans indicated the presen ce of decorin at each developmental stage. Longissimus dorsi and bicep s femoris collagen concentrations (5.13 +/- 0.9 vs. 5.53 +/- 1.5%, res pectively) and crosslink concentrations (0.07 +/- 0.01 moles HP/mole c ollagen) were initially similar between the two muscles; however, by s ix-months the muscles differed in both collagen concentration (1.72 +/ - 0.5 and 2.53 +/- 0.7%, respectively) and crosslinking (0.24 +/- 0.02 and 0.27 +/- 0.03 moles HP/mole collagen, respectively). At six years of age, both the longissimus dorsi and biceps femoris exhibited sligh tly elevated collagen concentrations (2.49 and 3.05%, respectively) wh ile crosslinking values were decreased relative to values at six-month s of age (0.11 +/- 0.01 and 0.18 +/- 0.01 moles HP/mole of collagen, r espectively). The results from this study indicate that skeletal muscl e proteoglycans and collagen show developmental changes, which suggest s that they are subject to developmental regulation.