Wenyang-Shengji ointment regulates GRP78/CHOP pathway to inhibit excessive endoplasmic reticulum stress for facilitating diabetic refractory wound repair / 中国病理生理杂志

ABSTRACT

AIM:To study the regulation of endoplasmic reticulum stress(ERS)using the glucose regulated protein 78(GRP78)/CCAAT/enhancer binding protein homologous protein(CHOP)pathway and explore the related mech-anism of Wenyang-Shengji ointment in facilitating the repair of diabetic refractory wounds.METHODS:To establish a rat model of diabetic refractory wound repair,Sprague-Dawley(SD)rats were fed a high-fat diet and intraperitoneally in-jected with streptozotocin.Subsequently,full-thickness skin defects were induced in the dorsal region of the rats.The ex-periment included 4 groups:normal,model(diabetic refractory wounds),Wenyang-Shengji ointment,and Beifuxin(re-combinant bovine basic fibroblast growth factor gel)groups.The normal and model groups were treated with normal saline after disinfection.In the Wenyang-Shengji ointment and Beifuxin groups,the wounds were topically treated with the re-spective ointments once daily.After 14 d of treatment,wound healing was assessed and quantified using the wound healing rate.Hematoxylin-eosin(HE)staining was employed to examine the micromorphology of the wound tissue.Western blot analysis was performed to measure GRP78,CHOP and caspase-12 levels in the wound tissue.Immunohistochemical analy-sis was used to detect the expression and distribution patterns of GRP78,CHOP and caspase-12 in the wounds.Transmis-sion electron microscopy was used to observe reticulum numbers and swelling.Enzyme-linked immunosorbent assay was used to determine interleukin-1β(IL-1β)level as a pro-inflammatory factor within the wound.RESULTS:Indexes of each group were assessed 14 d after the corresponding intervention.Compared with normal group,the rats in model group exhibited a significant decrease in the wound healing rate(P＜0.01),accompanied by increased inflammatory exudation and poor granulation tissue growth.Additionally,there were increases in the expression levels of GRP78,CHOP and cas-pase-12 proteins(P＜0.01),as well as a significant elevation in the content of inflammatory factor IL-1β(P＜0.01).In contrast,compared with model group,treatment with Wenyang-Shengji ointment resulted in a significant improvement in wound healing rate(P＜0.01),reduction in inflammatory exudation,and enhanced granulation tissue growth(P＜0.01).Furthermore,there was a notable decrease in the protein expression of GRP78/CHOP/caspase-12 within the wound tissue following treatment with Wenyang-Shengji ointment(P＜0.01).The levels of inflammatory factor IL-1β also showed a sig-nificant decrease(P＜0.01).CONCLUSION:Wenyang-Shengji promotes the healing of diabetic refractory wounds,which may be associated with the downregulation of the GRP78/CHOP pathway,inhibition of excessive ERS,and reduc-tion in the level of wound cell apoptosis.