[Influence of repeatedly injecting platelet-rich plasma on survival and quality of fat grafts in nude mice].

Objective: To study the effect of platelet-rich plasma (PRP) on the survival and quality of fat grafts in the nude mice so as to provide a method and the experimental basis for clinical practice.
Methods: Fat tissue was harvested from the lateral thigh of a 25-year-old healthy woman and the fat was purified by using saline. The venous blood was taken from the same donor. PRP was prepared by centrifugation (200 x g for 10 minutes twice) and activated by 10% calcium chloride (10 : 1). Then 24 female nude mice [weighing (20 +/- 3) g, 5-week-old] were allocated randomly to the experimental group and the control group (12 mice per group). Each subcutaneous layer of two sides of the back (experimental group) was infiltrated with 0.8 mL fat tissue-activated PRP mixtures (10 : 2); the control group was infiltrated with 0.8 mL fat tissue-saline mixtures (10 : 2); 0.14 mL activated PRP and 0.14 mL saline were injected into the experimental group and the control group respectively at 5 and 10 days after the first operation. At 15, 30, 90, and 180 days after the first operation, the samples were harvested for gross and histological observations.
Results: All nude mice survived to the end of the experiment. No inflammation and abscess formation of the graft were observed. Experimental group was better than control group in angiogenesis, liquefaction, and necrosis. The grafted fat weight and volume in the experimental group were significantly larger than those in the control group at 15, 30, and 90 days (P < 0.05); but there was no significant difference between the 2 groups at 180 days (P > 0.05). Histological observation showed good morphological and well-distributed adipocytes, increasing vacuoles, few necrosis and calcification in the experimental group; but disordered distribution, obvious necrosis, and calcification in the control group. The necrosis area ratio of the experimental group was significantly lower than that of the control group (P < 0.05), and the number of micro-vessels was significantly higher in the experimental group than in the control group at 15 and 180 days (P < 0.05).
Conclusion: The method of repeatedly using the PRP within 180 days in assisting fat grafts can obviously improve the survival and quality.