Antioxidant-Rich Extract from Plantaginis Semen Ameliorates Diabetic Retinal Injury in a Streptozotocin-Induced Diabetic Rat Model

Abstract

Plantaginis semen, the dried ripe seed of Plantago asiatica L. or Plantago depressa Willd. (Plantaginaceae), has been traditionally used to treat blurred vision in Asia. The aim of this work was to investigate the effect of plantaginis semen ethanol extract (PSEE) on the amelioration of diabetic retinopathy (DR) in streptozotocin (STZ)-diabetic rats. PSEE has abundant polyphenols with strong antioxidant activity. PSEE (100, 200 or 300 mg/kg) was oral administrated to the diabetic rats once daily consecutively for 8 weeks. Oral administration of PSEE resulted in significant reduction of hyperglycemia, the diameter of the retinal vessels, and retinal vascular permeability and leukostasis in diabetic rats. In addition, PSEE administration increased the activities of superoxidase dismutase (SOD) and catalase (CAT), and glutathione peroxidase (GSH) level in diabetic retinae. PSEE treatment inhibited the expression of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor-1α (HIF-1α) and the phosphorylation of Akt without altering the Akt protein expression in diabetic retinae. PSEE not only down-regulated the gene expression of hypoxia-inducible factor-1α (TNF-α) and interleukin-1β (IL-1β), but also reduced ICAM-1 and VCAM-1 expression in diabetic retinae. Moreover, PSEE reduced the nuclear factor-κB (NF-κB) activation and corrected imbalance between histone deacetylases (HDAC) and histone acetyltransferases (HAT) activities in diabetic retinae. In conclusion, phenolic antioxidants extract from plantaginis semen has potential benefits in the prevention and/or progression of DR.

Scutellarin Prevents Angiogenesis in Diabetic Retinopathy by Downregulating VEGF/ERK/FAK/Src Pathway Signaling

“…Journal of Diabetes Research to insulin, is the hallmark of type 2 diabetes mellitus (T2DM). Insulin resistance always results in damage to small blood vessels, especially diabetic retinopathy (DR) [34][35][36]. DR is one of the most common diabetic microvascular complications and is a leading cause of blindness.…”

Administration of human umbilical cord blood mononuclear cells restores bladder dysfunction in streptozotocin‐induced diabetic rats

“…Consistent with these previous reports, in the present study, HUCB‐MNC treatment abrogated the increased expression of VEGF in bladders of diabetic rats 4 weeks after the induction of diabetes. Previous studies showed that retinal VEGF gene and protein expression increased significantly in diabetic rats . Furthermore, earlier data reported a permanent increase in renal VEGF gene expression after 3 weeks of diabetes but not in long‐term diabetes .…”

“…Previous studies showed that retinal VEGF gene and protein expression increased significantly in diabetic rats. 62,63 Furthermore, earlier data reported a permanent increase in renal VEGF gene expression after 3 weeks of diabetes but not in long-term diabetes. 64 Conversely, Jang et al 65 showed that HUCB-derived mesenchymal stem cells had beneficial effects on renal ischemia-reperfusion injury through humoral effects and the induction of VEGF secretion.…”

Is leukostasis a crucial step or epiphenomenon in the pathogenesis of diabetic retinopathy?

“…These latter 2 processes have also been implicated in increased retinal leukostasis. Systemic administration of AGEs leads directly to increased retinal leukostasis in mice [48], whereas various antioxidant therapies neutralize the diabetes-induced increase in leukostasis [14,61].…”