[Relationship of atherogenesis and proteoglycans in wall of vein graft, an experimental study]

To investigate the relationship between the concentrations of proteoglycans (PGs) and progress of atherogenesis in grafted vein.

A section of common carotid artery with a length of 0.5 cm was cut off and then a section of vein was implanted to the damage among 72 male New Zealand rabbits. Then the rabbits were randomly divided into two groups of 36 rabbits to be fed with high fat diet and ordinary diet respectively. Every six rabbits were killed one week, 2 weeks, 4 weeks, 8 weeks, 12 weeks, and 20 weeks after the operation. The implanted veins were taken to be observed by electron microscopy. The PGs in the implanted veins were extracted and divided into heparan sulfate proteoglycan (HSPG), chondroitin sulfate proteoglycan (CSPG), and dermatan sulfate proteoglycan (DSPG) by anion-exchange chromatography 8, 12, and 20 weeks postoperatively. The concentrations of PGs were measured. Blood was extracted from the heart to examine the level of LDL-cholesterol. The normal jugular veins on the opposite side were used as controls.

The level of LDL-cholesterol in the high fat diet group was 26.5 +/- 7.49 mmol/L, significantly higher than that in the normal diet group (0.71 +/- 0.65 mmol/L, P < 0.05). In the normal diet group, the content of CSPG-DSPG was 1,077 +/- 116 micro g/g, significantly higher than that of the normal vein (809 +/- 75 micro g/g, P < 0.05), and not significantly different from that of the normal diet group (1,077 +/- 116 micro g/g) 8 weeks postoperatively, and became lower 12 and 20 weeks postoperatively (773 +/- 49 and 819 +/- 45 micro g/g respectively), both similar to that of normal vein (both P > 0.05). Foam cells were found 20 weeks postoperatively. In the high fat diet group, the content of CSPG-DSPG was 1,089 +/- 94 micro g/g 8 weeks postoperatively, significantly higher than that of normal vein (P < 0.05), and the high level lasted till the 20 th postoperative week (1,068 +/- 100 micro g/g, P < 0.05). Foam cells were detected as early since the 4 th postoperative week, unorganized areas were found 20 weeks after the operation. The HSPG content was not significantly different among the high fat diet group, normal diet group, and the normal vein (with a range of 213 +/- 34 - 278 +/- 33 micro g/g), The proportion of HSPG in total PGs 8, 12, and 20 weeks postoperatively in the high fat diet group were 19.6%, 18.6%, and 16.6% respectively, lower than those in the normal diet group (18.8%, 21.9%, 21.9%) and much lower than that in the normal vein (25.55%).

CSPG-DSPG has auxo-action on atherogenesis in graft, but HSPG protects the graft against atherogenesis to an extent.