Effect of immunosuppression on the prevention of calcification in rat aortic valved homograft / 中华胸心血管外科杂志

ABSTRACT

Objective Calcification and graft failure may occur in aortic valved homografting as a result of immune rejection. This study was designed to examine the effects of immunosuppression in reducing immune rejection response and preventing calcification in rat aortic valved homograft(AVH). Methods Animals were randomly assigned into 3 test groups and 1 control group. SD-Wistar rats in the test groups received AVH of cryopreservation (group A), received AVH of cryopreservation followed by CsA treatment (group B), and received AVH preconditioned with monoclonal antibody against dendritic cells (DcmAb) diluted in 15 and cryopreserved then were treated with DcmAb postoperatively (group C), respectively. Rats in the control group(group D) were Wistar→Wistar.Rat AVH with myocardial cuff were transplanted into the abdominal aorta of rats. The rats were sacrificed in batchs at 2, 4, 8, 12 and 16 weeks postoperatively. Blood samples were obzained for detecting the expression of TCR-αβ, CD28. The AVH specimens were obtained for observing the change of endotheliocyte and smooth muscle cells with light and electron microscopes. At the same time, calcium contents of AVH tissues after transplantation were measured. Results As compared with the control group, the expression of TCR-αβ and CD28 in test groups was increased significantly at each time point(P<0.01) and reached peaks 2 to 4 weeks after operation, then gradually reduced and was closed to the level of controls at 12 weeks. Calcium contents of AVH tissues in the test groups was increased gradually since 4 weeks and reached the peak 12 to 16 weeks after operation. No significant difference in calcium level was found in the control group over 5 different periods (P>0.05). Calcium contents of AVH tissues at 4 and 8 weeks postoperatively were (2856±79)μg/g and (3587±168)μg/g in the groups with cryopreservation;(2518±73)μg/g,(3237±187)μg/g in the CsA treatment group;(2176±210)μg/g, (3089±176)μg/g in the DCmAb treatment group; (860±60) μg/g, (870±50) μg/gin the control group. Conclusion The immunosuppressive treatment had substantial effects on AVH calcification as a result of reduction in immune rejection response and delay in the development of calcification.