Objective:To discover the influence within four hours of different storage time in vitro on the osteogenic capability in bone autograft.Methods:The ilium blocks in 0.9% saline were kept at room temperature for 0、1、2、 3 or 4 hours before replacement to extra-skeletal muscle gaps in the same rabbit.The grafts transplanted to muscle gaps were divided into two types:irrigating bone marrow with saline and non-irrigating bone marrow.The histological specimens of the autograft in extra-skeletal muscle gaps were taken at the 3rd day and 1、2、4、6 weeks after operation

stained by ALP.PAS and HE

and analysed by histomorphometry.Results:There were survival osteocytes and osteoblasts in all ectopic graft groups three days after operation

but no new bone formation.New osteoid tissues were formed one week after operation

and they increased at the second week and were gradually transformed into woven bone and lamellar bone tissues in all ectopic graft groups. The results of histomorphometry analysis showed there was no remarkable difference among all ectopic graft groups.Conclusion:Storage of the bone blocks in 0.9% saline for four hours before implant has no remarkable influence on the capacity of bone formation in bone autograft.Irrigating bone marrow with saline would not influence the survival of autograft and the capacity of new bone formation.Therefore

it is a reasonable method to keep bone blocks in saline before implant.