The preparation of VEGF/bFGF-loaded poloxamer thermosensitive gels and the promotive effect of the gels on the skin wound healing in rats / 国际药学研究杂志

ABSTRACT

Objective: To prepare the vascular endothelial growth factor(VEGF)and basic fibroblast growth factor(bFGF)-loaded poloxamer thermosensitive gels and investigate the in vitro drug release property as well as the therapeutic effect of the drug-loaded thermosensitive gels on the full-thickness skin defected wound healing in rats. Meth- ods The release of VEGF and bFGF from the drug-loaded gels in vitro was determined by the membrane release meth- od. The full-thickness skin defected model of rats was established and divided into four groups the normal saline(Con- trol)group, poloxamer thermosensitive gel(Gel)group, freeze-dried VEGF and bFGF powder(VEGF/bFGF powder) group, and the VEGF/bFGF-loaded poloxamer thermosensitive gel(VEGF/bFGF-loaded gel)group. The wound healing was observed on the 3rd, 7th and 14th day of injury. The wound tissue was stained with hematoxylin-eosin. The wound healing and inflammation were observed under the microscope. The expression of CD31 was measured by the immunohis- tochemical staining and the number of new blood vessels was counted. The content of inflammatory factors in the wound was detected by ELISA. Results: The VEGF/bFGF-loaded poloxamer thermosensitive gels were successfully prepared. The in vitro drug release test showed that only about 5% of VEGF and bFGF in the drug-loaded gels was released from the gels within 1 h of the test, however, the subsequent VEGF and bFGF release could reach 60% on the fifth day of the re- lease test, suggesting the well sustained drug-release behavior of the VEGF/bFGF-loaded gels. In the wound healing test using the full-thickness skin defected rat model, the wound healing rate reached(90.3±2.4)% on the 14th day of injury, in the VEGF/bFGF-loaded gel group, which was significantly higher than that in the other groups(P<0.05). On the 3rd day of injury, compared with the Control and Gel groups, the level of IL-6 and TNF-α in the wound was significantly de- creased in the VEGF/bFGF-loaded gel group(P<0.05). The tissue HE staining showed that the skin wound healed well in the VEGF/bFGF-loaded gel and the VEGF/bFGF powder groups, and a lager number of neovascularization and the epi- dermis appeared earlier in both the VEGF/bFGF-loaded gel and the VEGF/bFGF powder groups than in the Control and the Gel groups. The immunohistochemical results further confirmed that the number of neovascularization was significant- ly higher in the VEGF/bFGF-loaded gel and the VEGF/bFGF powder groups than in the Control and Gel groups(P< 0.05). Conclusion: The prepared VEGF/bFGF-loaded poloxamer thermosensitive gels in the present study could be used to repair the full-thickness skin defected wound in rats, which could reduce the early inflammatory reaction, pro- mote the angiogenesis, and thus accelerate the healing.