Evaluation of poly (ethylene glycol–propylene glycol) copolymer bone hemostatic agent containing gentamicin for enhancing local antibacterial and anti-inflammatory effects in an infected calvarial defect rat model

Abstract

Bone wax is the most commonly used hemostatic agent in surgery; however, it is non-absorbable and may act as a nidus of infection. Thus, new hemostatic agents that are absorbable and have antibiotic effects are needed. In this study, we assessed the hemostatic ability, bioabsorption, and local antibiotic and anti-inflammatory effects of a newly developed poly(ethylene glycol–propylene glycol) (PEG-PPG) copolymer containing gentamicin (PEG-PPGg) in a calvarial defect rat model. A total of 100 Sprague Dawley rats were used in this study. Twenty were used to determine time to hemostasis and bioabsorption of PEG-PPGg. The remaining rats were assigned to four groups: two groups were infected with Staphylococcus aureus in the calvarial defects and treated with PEG-PPGg or PEG-PPG, and two non-infected groups were likewise treated with PEG-PPGg or PEG-PPG. Hemostasis was completed within 10 s in all defects and PEG-PPGg was absorbed within three days. Systemic inflammation did not significantly differ among the groups (P > 0.05). Early necropsies (three days and one week) suggested reduction of bacterial infection after application of PEG-PPGg. Histopathological examination showed that infected calvarial defects treated with PEG-PPGg had less local inflammatory cell infiltration and a lower degree of osteonecrosis than those treated with PEG-PPG (P < 0.05). In conclusion, PEG-PPGg showed immediate hemostatic effects and bioabsorption and displayed local antibiotic and anti-inflammatory effects in an infected calvarial defect rat model. Therefore, PEG-PPGg can be used as a bone hemostatic agent for controlling both bone bleeding and bacterial infection.