Prevention and treatment of andrographolide combined with gentamicin for burn wound infection in mice

Abstract:

Objective：To study the effect of andrographolide combined with gentamicin on burn wounds infection. Methods：The burn model infected by Pseudomonas aeruginosa mixed with Staphylococcus aureus was established in 48 BALB/c mice，with four wounds in each. The wounds in each mouse underwent blank intervention（control group），gentamicin intervention（gentamicin group），andro－grapholide intervention（andrographolide group） and andrographolide combined with gentamicin intervention（combined intervention group） respectively. The tissue necrosis was observed under pathological section，and the morphology of mixed biofilm by scanning electron microscopy. The expressions of tumor necrosis factor-α（TNF-α），interleukin-6（IL-6） and interleukin-1β（IL-1β） were de－tected by ELISA. The mixed biofilm model in vitro was established. The expression of exotoxin A（ExoA） was detected by Western blot and the expressions of exoS and exoY by qPCR. Results：Electron microscopy confirmed the successful modeling and biofilm de－struction under different interventions. The pathological scores showed that the prognosis of combined intervention group（4.86±0.38） was better than that of gentamicin intervention group（3.29±0.49） and andrographolide intervention group（4.14±0.69），with P value as 0.000 and 0.02，respectively. ELISA showed that the expres－sions of IL-1β，IL-6 and TNF-α in gentamicin intervention group decreased significantly than those in combined interven－tion group（P<0.05）. Western blot showed that the gray values of ExoA in the supernatant and bacterial cells of the gentamicin intervention group were 43.73±1.07 and 73.53±1.90 respec－tively，which were significantly higher than those in the com－bined intervention group（40.99±0.57 and 53.37±2.31）（P=0.017，P=0.000）. The expressions of exoS and exoY in the gentamicin intervention group were higher than those in the combined intervention group，with P values as 0.003 and 0.011. Conclusion：Andro－grapholide enhances the effect of gentamicin on the repair of burn wounds，which is related to the effects that andrographolide can promote the destruction of biofilm，and the reduction of inflammatory factors and virulence factors.