Objective: By observing the changes in the number and activity of CD34+ cells in bone marrow after predeposit autotransfusion (PAT) to patients with femoral shaft fracture (FSF), to evaluate the effects of PAT on hematopoietic function and hematopoietic stem cells in bone marrow.

Methods: Selected FSF patients were randomly divided into 2 groups: the control group (patients did not receive blood transfusion after surgery) and PAT group (patients received PAT after surgery). The content of RBC and Plt in blood samples were counted by blood routine. The cell cycle and proportion of CD34+ myelinated cells in blood samples was analyzed by flow cytometry. The telomere DNA length of hematopoietic stem cells (HSCs) in the control groups and PAT group at postoperation 24 was analyzed by southern blot.

Results: The content of RBC and Plt in postoperation 6h and 24h in the control group was evidently higher compared to that in PAT group, while Hb content in control group was significantly lower compared to that in PAT group. The proportion of CD34+ myelinated cells in post-transfusion 6h and postoperation 24h in PAT group was evidently higher compared to that in the control group. In PAT group, S phase at postoperation 24h was significantly larger compared to that at post-transfusion 6h. The telomere DNA length of HSCs in PAT group was longer than that in the control group.

Conclusion: PAT can increase the number of HSC, while doesn't cause the abnormal aging of HSCs. PAT is suitable for postoperative blood transfusion of patients with FSF.