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Publisher Summary This chapter discusses a study to analyze the effect of high-density lipoproteins (HDL) and its fractions on in vitro collagen fibril formation. The effect of low density lipoproteins (LDL) and HDL on collagen fibril formation was studied by the heat gelation method. Collagen type I and III were extracted from rat skin and fractionated. Collagen type II was extracted from nasal cartilage. LDL and HDL fractions were prepared according to Kostner and Holasek (1977) from pooled serum. LDL and very low-density lipoproteins (VLDL) were precipitated by phosphotungstic acid (PTA)-magnesiumchloride. HDL was obtained from the supernatant after centrifugation at the specific gravity of 1.220, for 48 h in ultracentrifuge Janetzky, type VAC 402 at 200,000× g . The supernatant was called unfractionated HDL. After washing, it was fractionated at the specific gravity of 1.110 for 24 h at 150,000×g. It was found that LDL did not influence, not even slightly, the rate of fibril formation. On the contrary, HDL used at the same concentration delayed in vitro fibril formation. |
