Objective  To investigate the in vivo sternal fixation of poly(butyl succinate) (PBS) and polylactic acid (PLA) alloy material by comparing its biocompatibility of polylactic acid (PLA).    Methods  Sixty SD rats were randomized into 4 groups (n=15). PBS

PLA and PBS/PLA alloy were implanted subcutaneously in the corresponding rat dorsum respectively. Sham group was designed as the control group without any material implantation. In 1

4

8

12 and 16 weeks after implantation

the implanted materials and the surrounding tissues were extracted from the rats

with 3 animal of each time points. The collected implants and surrounding tissue samples were sectioned and stained with hematoxylin and eosin and Masson for histological changes. In addition

the terminal deoxynucleotidyl transferase(TdT)-mediated UTP nick end labeling (TUNEL) apoptosis assay were used for assessment of the subcutaneous tissue apoptosis.    Results  The PBS/PLA alloy group showed no obvious difference in local acute and chronic inflammation response in contrast with PLA and PBS groups. The thickness of the fiber capsule surrounding the implants in PBS/PLA alloy group was between that of PLA group and PBS group (P0.05). The tissue apoptosis in the 3 groups demonstrated no obvious difference statistically (P0.05).    Conclusion  In contrast with PLA

the PBS/PLA alloy has an acceptable sound in vivo biocompatibility.