Systemic and local inflammatory response after implantation of biomaterial in critical bone injuries

Purpose: To evaluate inflammatory response in critical bone injuries after implantation of the biomaterial composed of hydroxyapatite (HA)/poly (lactic-coglycolic acid) (PLGA)/BLEED. Methods: Forty-eight male Wistar rats (280 +/- 20 grams) were divided into two groups: control group (CG), in which the animals do not receive any type of treatment; and biomaterial group (BG), in which the animals received the HA/PLGA/BLEED scaffold. Critical bone injury was induced in the medial region of the skull calotte with the aid of a trephine drill 8 mm in diameter. The biomaterial was implanted in the form of 1.5-mm thick scaffolds. Serum and calotte were collected at one, three and seven days. Results: Biomaterial had a significant effect on the morphological structure of the bone, accelerating osteoblast activation within three days, without causing exacerbated systemic inflammation. In addition, quantitative real-time polymerase chain reaction (qRT-PCR) analysis showed that BG induced upregulation of osteogenic genes such as runt-related transcription factor 2, and stimulated genes of inflammatory pathways such as tumor necrosis factor-alpha, on the first day without overexpressing genes related to bone matrix degradation, such as tissue inhibitor of metalloproteinases-1 and matrix metalloproteinase-9. Conclusion: The HA/PLGA/BLEED (R) association can be used as a bone graft to aid bone repair, as it is capable of modulating expression of important genes at this stage of the repair process.

Automated summary

The study found that HA/PLGA/BLEED biomaterial implantation had a significant effect on the morphological structure of bone and accelerated osteoblast activation within three days without causing exacerbated systemic inflammation. In addition, it was found that the biomaterial modulated the expression of important genes involved in bone repair.