Objective: To compare the platelet enrichment ratio of platelet-rich plasma (PRP) prepared by different centrifuge methods and to compare the concentration of growth factors released from autologous platelet-rich gel (APG) with the whole blood.

Methods: Thirteen diabetic patients with refractory skin lesions were enrolled in APG treatment. (1) Three kinds of centrifuge methods were selected for PRP by 11 diabetic patients: A (n = 6): 529 x g for 4 minutes in the first centrifuge and 854 x g for 6 minutes in the second centrifuge; B (n = 5): 313 x g for 4 minutes in the first centrifuge and 1,252 x g for 6 minutes in the second centrifuge; C (n = 5): 176 x g for 5 minutes in the first centrifuge and 1,252 x g for 5 minutes in the second centrifuge. Platelet counted on the whole blood and PRP was determined. The APG, produced by combining the PRP with thrombin and calcium gluconate (10:1) was used by patients. (2) PDGF-BB, TGF-beta1, VEGF, EGF, and IGF-1 were measured in the APG and the whole blood using the enzyme-linked immunosorbent assay method.

Results: (1) The average platelet concentration was higher in group B [(1,363.80 +/- 919.74) x 10(9)/L] than in groups A [(779.67 +/- 352.39) x 10(9)/L)] and C [(765.00 +/- 278.78) x 10(9)/L] and the platelet recovery rate was 75.2% +/- 21.0% in group B. (2) The concentration of growth factors all increased with the increasing platelet number. On average, for the whole blood as compared with APG, the PDGF-BB concentration increased from (145.94 +/- 133.24) pg/mL to (503.81 +/- 197.86) pg/mL (P < 0.05); TGF-beta1 concentration increased from (3.31 +/- 2.27) ng/mL to (5.67 +/- 4.80) ng/mL (P < 0.05); IGF-1 concentration increased from (14.54 +/- 35.34) ng/mL to (110.56 +/- 84.36) ng/mL (P < 0.05); and EGF concentration increased from (160.73 +/- 71.10) pg/mL to (265.95 +/- 138.43) pg/mL (P < 0.05). No increase was found for VEGF (P > 0.05). (3) There was positive correlation between the platelet concentration and PDGF-BB and TGF-beta1 (r = 0.627, r = 0.437, P < 0.05). (4) Thirteen diabetic repractory dermal ulcers received APG treatment for 18 times, 9 ulcers (69.2%) and 10 sinuses (88.3%) were cured at the end of 12-week treatment.

Conclusion: The method of group B is the best centrifuge method. A variety of growth factors are detected and released from the platelets at significant levels in APG. There is positive correlation between the platelet concentration and PDGF-BB and TGF-beta1.