ABSTRACT
This study aimed to determine the protective effect of Qizhi hypoglycemic tablet (QZHGT) on foot ulcer in diabetic rats and explore its possible mechanism. Diabetes was induced by streptozotocin injection in rats. The rats received QZHGT (780 mg·kg-1), metformin hydrochloride tablet (Metf, 200 mg·kg-1) or glibenclamide tablet (Glib, 1.5 mg·kg-1) alone via intragastric administration once a day for three months. Food ulcer was prepared by foot skin excision after drug therapy lasted for two months, and the dynamic changes in food ulcer healingwere determined. During the experiment, blood glucose, serum levels of vascular endothelial growth factor (VEGF) and inducible nitric oxide synthase (iNOS), factor Ⅲ (FⅢ) and four coagulation parameters [thrombin time (TT), activated partial thromboplatin time (APTT), prothrombin time (PT), fibrinogen (FIB)] were detected. Finally, the protective mechanisms of QZHGT against diabetes and foot ulcer were analyzed by network pharmacology, and immunohistochemistry was used to confirm the expression of transforming growth factor-β (TGF-β) and nuclear factor κB (NF-κB) in pancreatic tissue. All animal procedures were approved by the Animal Experimentation Ethics Committee of Henan University (permission number HUSAM 2016-288). The results showed that the lasting hyperglycemia, polydipsia, polyphagia, polyuria and body weight lost took place in model rats compared to those in normal rats. These model rats also showed an increase in serum VEGF and iNOS, FⅢ, TT, APTT and PT, and a reduction in FIB and wound healing. Metf or Glib significantly improved hyperglycemia, polydipsia, polyphagia, polyuria and emaciation, but failed to ameliorate hypercoagulation and wound healing. QZHGT showed a similar effect on polydipsia, polyphagia, polyuria and emaciation to Metf or Glib, although it was inferior to them in hypoglycemic action. Importantly, QZHGT significantly improved hypercoagulation and wound healing, and attenuated serum VEGF and iNOS. Network pharmacology revealed that QZHGT decreased hyperglycemia through "insulin resistance pathway", improved coagulation status through "HIF-1 signaling pathway", prevented diabetic foot ulcers through "VEGF signaling pathway", "MAPK signaling pathway" and "NF-κB signaling pathway". Immunohistochemistry showed that QZHGT could inhibit the expression of TGF-β and NF-κB in pancreatic tissue to maintain islet function in diabetic rats. In summary, these data suggest that QZHGT can prevent pancreatic injury for adjunctive hypoglycemia and diabetic foot ulcer treatment, and is a better preventive and therapeutic drug for diabetic foot ulcer.