Résumé
BACKGROUND: Platelet-rich plasma (PRP) contains abundant growth factors that were needed for osteanagenesis. Moreover,the proportion of each growth factor formed by an organism, with good synergism.OBJECTIVE: To explore the influence of PRP on osteogenetic activity of canine bone marrow mesenchymal stem cells (BMSCs) after induction in vitro.DESIGN, TIME AND SETTING: The in vitro cytological experiment was performed at the Central Laboratory of Xiangya Hospital of Central South University from June 2007 to February 2008.MATERIALS: Healthy 12-month male Beagle dogs were supplied by the Experimental Animal Center, Xiangya Medical College,Central South University.METHODS: The 3~(rd) generation BMSCs were collected and divided into 4 groups. BMSCs in the control group were incubated in standard medium. BMSCs in the osteogenetic induction medium group were incubated in high-glucose DMEM containing fetal calf serum, dexamethasone, beta-sodium glycerophosphate and vitamin C. BMSCs in the PRP group were incubated in low-glucose DMEM containing 6.25% PRP. BMSCs in the combination group were incubated in high-glucose DMEM containing 6.25% PRP, dexamethasone, beta-sodium glycerophosphate, and vitamin C.MAIN OUTCOME MEASURES: Alkaline phosphatase activities were measured. Expression of collagen type I was examined by immunocytochemical staining. Calcium tuberoses were labeled using modified Von Kossa staining. Expression of osteocalcin mRNA was examined by RT-PCR.RESULTS: Levels of alkaline phosphates of all groups became increased along with time. The alkaline phosphates level of combination group was strongest (P < 0.05). Following 7 and 14 days of induction, type I collagen expressed positively in the osteogenetic induction medium and combination groups, but negatively in the PRP and control groups. Following 14 days,formation of calcium nodules were found in the osteogenetic induction medium and combination groups. Following 7 and 14 days,expression of osteocalcin mRNA were similar between the control and PRP groups (P > 0.05), which was significantly lower than the osteogenetic induction medium and combination groups (P < 0.05). Expression of osteocalcin mRNA was significantly lower in the osteogenetic induction medium group compared with the combination group (P < 0.05).CONCLUSION: PRP gel can effectively promote osteoblastic effect of BMSCs after induction in vitro following induction in osteogenetic medium.
Résumé
BACKGROUND: Proliferation and differentiation of mesenchymal stem cells (MSCs) is associated with platelet concentration in platelet-rich plasma (PRP). Low enrich multiple cannot reach proper effects, but high level had inhibitory effects on osteoanagenesis.OBJECTIVE: To observe the effect of different volume fraction of PRP on dog BMSC proliferation.DESIGN: A cytological in vitro study.MATERIALS: Healthy 12-month male Beagle dogs were supplied by the Experimental Animal Center, Xiangya Medical College,Central South University.METHODS: Dog BMSCs of 5 passage were adjusted to 3×10~8/L, and incubated in a 96-well plate at 200 μL per well. Following 24 hours of routine culture, primary medium and non-adherent cells were discarded. Prepared PRP gel was mixed with serum-free low-glucose DMEM containing penicillin and streptomycin, and then diluted into 5%, 6.25%, 7.5%, 8.75%, 10% volume fraction. 200 μL above-described liquid was added into the 96-well plate, which was subsequently placed in a incubator.We set up a blank control.MAIN OUTCOME MEASURES: MTT was used to investigate effect of different volume fraction of PRP on dog BMSC proliferation.RESULTS: Compared with the blank control group, various volume fraction of PLP could promote dog BMSC proliferation in early stage. With prolonged time, proliferation speed began to increase at day 6 in the 8.75% and 10% PRP groups, entering platform stage. BMSC number was increased rapidly in the 5% and 6.25% PRP groups, especially in the 6.25% PRP group.CONCLUSION: PRP gel could promote BMSC proliferation markedly and proliferation strength of BMSCs was correlated to the density of PRP. BMSC proliferation would be accelerated by the low density of PRP.