Influence Of Mixing Blood With Calcium Phosphate Cement/Poly(Lactide-CO-Glycolide) Composite On The Degradation Osteogenesis

OBJECTIVETo evaluate the effects on the degradation osteogenesis of CPC/PLGA by the whole blood.METHODSPreparation of CPC/PLGA composite:the PLGA particles (particle size 75μm-150μm) was mixed to the CPC (mass ratio PLGA:CPC=1:4).Preparation of rabbit skull defects:Circular defects were formed by removing a diameter of 8mm of cortical on both sides of the rabbit skull raphe.Three groups were set in this experiment. ① CPC/PLGA group (control group):The CPC/PLGA composite was mixed evenly with solidifying liquid by powder-liquid (P/L) ratio of 0.5ml/g. ② CPC/PLGA+10% Blood Group: CPC/PLGA powder was mixed with solidifying liquid(P/L ratio is 0.5ml/g) followed by adding whole blood (blood volume and CPC powder mass ratio is 1/10.) from auricular veins of the rabbits.③ CPC/PLGA+20% Blood Group: CPC/PLGA powder was mixed with solidifying liquid(P/L ratio is 0.5ml/g) followed by adding whole blood (blood volume and CPC powder mass ratio is 2/10.) from auricular veins of the rabbits. After mixing, three groups composite were filled in the Teflon rings and then implanted over the rabbit skull defects. Four rabbits from each group were killed at 8 and 12 weeks after, and the morphologic changes of HA were histologically evaluated. Specimens were made of paraffin, hematoxylin-eosin (HE) staining to analyze the degradation of the composite. Three groups of new bone ingrowth height and new bone area ratio were analysis by variance and LSD pairwise comparison of SPSS 16.0 statistical software.RESULTSAfter 8 weeks, in CPC/PLGA group, only a small amount of bone was generated at the edge and bottom of the material. Within the material showed no degradation of PLGA. CPC/PLGA+10% blood group showed more capillaries, bone and osteoid generating alternative biodegradable materials. PLGA between new tissue was almost completely degraded. But the degradation of PLGA within the material increased slightly. Rich new bone tissue was observed in CPC/PLGA+20% blood group, and new bone ingrowth height even reached 1.55 mm, which showed active osteogenesis.After 12 weeks, new bone height and new bone ingrowth area ratio in CPC/PLGA and CPC/PLGA+10% blood group were significantly increased than 8 weeks (P< 0.05). But in CPC/PLGA group new bone mainly concentrated on both sides of the material. The PLGA particles within material appeared a small amount of degradation. CPC/PLGA+10% blood group and CPC/PLGA+20% blood group of the bone trabecular plate shaped, and some was similar to skull plate laminar. Osteoblast significantly reduced, which indicated that osteogenesis tended to be stable. PLGA inside material appeared different degree of degradation.Bone ingrowth height:After 8 weeks, new bone ingrowth height CPC/PLGA+20% blood group (0.522±0.044mm)> CPC/PLGA+10% blood group (0.195±0.029mm)> CPC/PLGA group(0.039±0.011mm). New bone ingrowth height difference between the three groups were statistically significant (P< 0.05). After 12 weeks, new bone ingrowth height CPC/PLGA+20% blood group(0.509±0.143mm)> CPC/PLGA+10% blood group (0.420±0.135mm)> CPC/PLGA group (0.101±0.029mm).The difference of new bone ingrowth height between CPC/PLGA group and two experimental was statistically significant (P<0.05). The difference of new bone ingrowth height between CPC/PLGA+10% blood group and CPC/PLGA+20% blood was not statistically significant (P>0.05).Newborn bone area ratio:After 8 weeks:the ratio of new bone area CPC/PLGA+20% blood group (7.67%)> CPC/PLGA+10% blood group (2.66%)> CPC/PLGA group (0.47%), among the three groups were statistically differences (P<0.05). After 12 weeks:the ratio of new bone area CPC/PLGA+ 20% blood group (10.92%)> CPC/PLGA+10% blood group (7.97%)> CPC/ PLGA group (1.70%), CPC/PLGA group and CPC/PLGA+10% blood group have significant difference (P<0.05), CPC/PLGA group and CPC/PLGA+ 20% blood group have significant difference (P<0.05), CPC/PLGA group and CPC/PLGA+20% blood group have no significant difference (P> 0.05).CONCLUSION:1. Adding an appropriate amount of whole blood in CPC/PLGA composite can promote the degradation osteogenesis.2. In the late stage of bone restoration, the osteogenesis effect of adding 10% and 20% whole blood in CPC/PLGA composite were similar.3. The osteogenesis of CPC/PLGA composite with 20% whole blood was most obvious.