The Effects of RGDS Tetrapeptide on the Calcification of the Bovine Pericardium Transplanted Subcutaneously in Rats

Jin, Ung; Lee, Ju Hyeon; Kim, Chi Kyung; Lee, Sun Hee

Abstract

BACKGROUND: All kinds of tissue valves must be pretreated for the inactivation of immunologic properties and the strengthening of tissue before implantation. However, the tissue valves are gradually denatured with the calcification process and they eventually lose their functions. Recent reports have shown the existence of specific calcium binding non collagenous proteins in the calcified area of implanted biomaterials. This experiment was intended to confirm the effect of pretreatment with RGDS(Arg-Gly-Asp-Ser) tetrapeptide on the calcification of subcutaneously implanted bovine pericardium in rats. RGDS tetrapeptide has the same amino acid sequence of attachment site of specific calcium binding non collagenous proteins. MATERIAL AND METHOD: All bovine pericardial pieces were fixed with 0.6% glutaraldehyde. The pretreatments were done using 5 different methods, group I ; with normal saline for 60 minutes, group II ; with 0.5% GRSD(Gly-Arg-Ser-Asp) tetrapeptide solution for 60 minutes, group III ; with 0.5% RGDS(Arg-Gly-Asp-Ser) tetrapeptide for 30 minutes, group IV ; with 0.5% RGDS for 60 minutes, and group V ; with 0.5% RGDS for 120 minutes. The pretreated bovine pericardial pieces were implanted subcutaneously at the abdominal sites of rats. 30 days after the implantation, the implanted bovine pericardial tissues were examined radiologically, biochemically, and histologically to measure the severity of calcification. RESULT: On the radiological examination, group I ; 68.42+/-3.06, group II ; 64.25+/-5.58 showed significant difference with group III ; 48.00+/-3.57, group IV ; 43.67+/- 2.31, and group V ; 42.58+/-2.47(p<0.05). There was no difference between group I and II(p=0.105). On the biochemical examination, the amount of calcium in group I was ; 33.09 +/- 6.59 mg, in group II ; 28.12+/-5.50 mg, in group III ; 25.42+/-7.67 mg, in group IV ; 20.51+/-5.11 mg, and in group V ; 15.43+/-4.25 mg. The group V showed significant difference with group I, II,III(p<0.05). There was no difference between I and II(p=0.388). On the histological examination, group I and II showed remarkable calcifications, and group III and IV showed minimal calcifications. However, no definite calcification was shown in group V.
CONCLUSION
These results showed that the pretreatment with RGDS tetrapeptide had a decreasing effect on the calcification of bovine pericardium implanted subcutaneously in rats.