MEBT/MEBO Promotes Chronic Non-healing Cutaneous Wound By Modulating The PI3K/Akt Signaling Pathway

ObjectiveCutaneous wound healing involves a complex mechanism with long-lasting courses,and ideal therapy and effective managements for chronic non-healing cutaneous wounds are lacking.Moist exposed burn therapy/Moist exposed burn ointment(MEBT/MEBO)has demonstrated satisfactory clinical benefits for chronic non-healing cutaneous wounds.We herein investigated tissue repairing effects of MEBT/MEBO in an experimental model of chronic non-healing cutaneous wounds in rats with mechanistic studies focused on PI3K/Akt/mTOR and IGF-1/PI3K/Akt signaling.Materials and Methods(1)Male SD rats were randomly assigned to normal group,acute wound group,and chronic wound group.After establishment of chronic non-healing cutaneous wound model,rats were evenly assigned to the model group,rb-FGF group,and MEBT/MEBO group.Healing time and rates of each group were recorded and calculated after initiation of treatment.(2)On days 3,7,and 14 post-treatment,tissues were collected from each group and examined histopathologically and also by scan electronic microscopy(SEM).Supernatant was separated from tissue specimens for measurement of IGF-1 by ELISA.(3)On days 3,7,and 14 post-treatment,proteins were extracted from tissue samples for detection of PI3K?p-Akt(S473)?p-mTOR(Ser2448)?p-p70 S6K(Thr389)?p-4E BP1(Thr37/46),p-eNOS,and VEGFR by Western blotting.Results(1)As compared with the model group,rats of the MEBT/MEBO group demonstrated significantly shortened healing time and greater healing rates.(2)Improvement in histopathological lesions was markedly observed in the MEBT/MEBO group than in the model group.(3)Significant improvement in full thickness wound was observed in the SEM images of the MEBT/MEBO group than those of the model group.(4)The MEBT/MEBO group exhibited significantly elevated IGF-1 levels than the model group did.(5)The MEBT/MEBO group exhibited markedly greater expression of PI3 K and phosphor-Akt than the model group did.Phosphorylation levels of mTOR and its downstream effector P70 S6 and 4E BP1 were significantly more elevated in the MEBO group than in the model group.(6)The MEBT/MEBO group showed markedly greater expression of PI3 K and phosphor-Akt than the model group did.Phosphorylation levels of eNOS and total levels of VEGFR2 were significantly more elevated in the MEBT/MEBO group than in the model group.ConclusionsMEBT/MEBO is effective in treating chronic non-healing cutaneous wound.The therapeutic benefits of MEBT/MEBO could result from enhanced angiogenesis via activation of the IGF-1/PI3K/Akt signaling as well as from activation of the PI3K/Akt/mTOR signaling pathway,the master regulator of multiple cellular functions including protein synthesis,ribosome biogenesis,and cell proliferation.