Thrombin powder

Approximately 10 ml of 0.9% NaCl solution (Saline solution) and 500 μg of bovine fibrinogen powder (500 mg, Solarbio, China) were slowly dissolved in a 50 mg/ml of bovine fibrinogen solution. The solutions were sterile-filtered using 0.22 μm pore filters. The entire process was conducted under sterile conditions at 37°C. Furthermore, 1000 U of thrombin powder (1000 U, Solarbio) was dissolved in 10 ml 0.9% NaCl solution to prepare a 100 U/ml thrombin solution at 25°C. The prepared solution was packaged and frozen for storage.

The preparation of the fibrin glue and the selection of the A2A receptor agonist and antagonist doses were based on the methods reported by several articles [27 (link)–30 (link)]. Briefly, fibrinogen powder (Solarbio, China) was dissolved in physiological saline into a concentration with 10 mg/ml at 37°C. Thrombin powder (Solarbio, China) was dissolved in 40 mmol/l calcium chloride solution, and the concentration was 20 μg/ml. Then, 5 mg CGS 21680 (specific adenosine A2A receptor agonist; Selleck, USA) or ZM 241385 (specific adenosine A2A receptor antagonist; Selleck, USA) was dissolved in 75 μl DMSO and mixed with thrombin solution into a concentration with 16 mg/ml CGS 21680 or ZM 241385 thrombin solution. Afterwards, 125 μl CGS 21680, ZM 241385, or thrombin solution (with DMSO as the solvent accelerating agent) was mixed with 125 μl fibrinogen solution to form a fibrin gel drug delivery system after 1 min of mixing.