[Effect of inhibiting perivascular adhesion on intimal hyperplasia of the vein grafts in rabbits]

Objective: To investigate the effect of preventing perivascular adhesion with topical application of sodium hyaluronate on intimal hyperplasia of the vein grafts in rabbits. Methods: Twenty-four male New Zealand white rabbits, aged 5 months, were randomly divided into 2 groups: Group A and B (n=12 rabbits per group). Artery defect model was established by cutting about 1 cm artery from the middle part of the dissociated left common carotid artery. A section about 3 cm was cut from the right external jugular vein, and the harvested vein was inverted and end-to-end anastomosed to the artery defect. After anastomosis, the adventitia and two anastomosis of the grafted veins in group A was applied 0.2 ml sodium hyaluronate locally to, and corresponding site in Group B was served as a control, but with the sterile normal saline. The grafted veins were obtained 1, 2 and 4 weeks after operation, HE staining and Masson staining were preformed for histological changes of grafted vein wall, proliferating cell nuclear antigen (PCNA) and platelet-derived growth factor (PDGF) immunohistochemistry staining were conducted for proliferation and expression and distribution of PDGF of the grafted vein. Results: The macroscopic and histological observation showed that the perivascular adhesions in Group A were looser when compared with those in Group B. The thickness of the intima, the degree of intima hyperplasia of 2 groups at different time points were as follows: at 1 week after operation, group A[(25.5±3.9) μm, (1.2±0.1) ]and group B[(26.2±4.2)μm, (1.2±0.1)]; at 2 weeks after operation, group A[(44.3±2.5)μm, (1.2±0.1)]and group B[(51.0±3.8)μm, (1.4±0.0)]; at 4 weeks after operation, group A[(69.9±6.8)μm, (1.5±0.1)] and group B[(84.4±6.4)μm, (1.7±0.1)]. Group A was inferior to group B in terms of the above three parameters 2 and 4weeks after operation (P<0.05). Cell proliferation index of intima and that of media were as follows: at 1 week after operation, group A (7.4±2.2), (21.5±3.2) and group B (11.5±2.0), (28.6±4.5); at 2 weeks, group A (20.0±3.2), (35.8±3.4) and group B (26.8±4.1), ( 42.6±4.2); at 4 weeks, group A (11.4±2.0), (22.1±2.7) and group B (15.5±2.4, 28.6±3.9). Group A was inferior to group B in terms of cell proliferation index of intima and media 1, 2 and 4 weeks after operation (P<0.05). The percentage of PDGF-positive cells of intima, media and adventitia was as follows: at 1 week after operation, group A (7.7±1.6), (19.6±3.7), (2.5±1.5) and group B (7.6±2.4), (20.6±4.4), (10.3±2.3); at 2 weeks after operation, group A (11.4±2.6), (19.8±3.1), (12.9±3.3) and group B (19.5±3.5), ( 30.6±5.2), (30.5±5.8); at 4 weeks after operation, group A (6.2±1.9), ( 11.1±2.8), (10.2±2.4) and group B (10.5±2.0), (18.6±3.2), (26.5±3.8). Group A was inferior to group B in terms of the percentage of PDGF-positive cells of intima, media and adventitia 2 and 4 weeks after operation (P<0.05) and Group A was inferior to group B that of adventitia 1 week after operation (P<0.05). Conclusion: Preventing perivascular adhesion with topical application of sodium hyaluronate can inhibit intimal hyperplasia.