Astragalus root extract inhibits retinal cell apoptosis and repairs damaged retinal neovascularization in retinopathy of prematurity

Exploring the impact of nano platinum-hydrogen saline on oxygen-induced retinopathy in neonatal rats

OBJECTIVE

The objective of this study is to assess the impact of nano platinum-hydrogen saline (Pt NPs + H2) on oxygen-induced retinopathy (OIR) in neonatal rats, with the goal to contribute new insights into the therapeutic strategies for retinopathy of prematurity.

METHODS

Pt NPs + H2 formulation was synthesized to address OIR in a rat model. Subsequent examination included the assessment of retinal blood vessel distribution and morphology through hematoxylin and eosin (HE) and isolectin B4 (IB4) staining techniques. The levels of reactive oxygen species (ROS), malondialdehyde(MDA), and superoxide dismutase (SOD) were measured to reflect the oxidative stress in rats. Additionally, the protein expression of vascular endothelial growth factor (VEGF) in each experimental group was assessed using western blot analysis, while the gene expression of VEGF in retinal neovascularization tissues was assessed using reverse transcription-polymerase chain reaction (RT-PCR). Furthermore, the extent of retinal cell apoptosis was measured using a TdT-mediated dUTP Nick-End Labeling (TUNEL) apoptosis kit.

RESULTS

HE staining and IB4 staining revealed positive retinal neovascularization in the OIR group, whereas neovascularization in the Pt NPs + H2 group exhibited reduced severity. Significantly fewer capillary globules and capillary tubules were observed in the Pt NPs + H2 group compared to the OIR group (p < 0.05). Also, the Pt NPs + H2 group demonstrated significant reductions in ROS and MDA levels within retinal tissues (p < 0.05, p < 0.001), along with a significant increase in SOD level (p < 0.05). Notably, the MDA level in the Pt NPs + H2 group was notably lower than that in the OIR group (p < 0.01, p < 0.05), and even lower than that in the H2 group. Pt NPs + H2 intervention was associated with decreased protein and mRNA expression of VEGF, with statistical significance (p < 0.05). While the H2 group exhibited a decreasing trend in apoptotic cell count in the retinal ganglion cell layer (p < 0.05), the Pt NPs + H2 group demonstrated a more pronounced reduction, with a significant difference (p < 0.01). No significant discrepancy in apoptosis within the inner nuclear layer was observed (p > 0.05).

CONCLUSIONS

The synergistic effect of hydrogen saline and nano platinum manifests as enhanced antioxidant, anti-apoptotic, and anti-neovascular properties. Nano platinum-hydrogen saline demonstrates inhibitory effects on OIR in rats.

Mechanisms of Astragalus membranaceus (Fisch.) Bge. var. mongholicus (Bge.) Hsiao (huang qi) and Angelica sinensis (Oliv.) Diels (dang gui) in Ameliorating Hypoxia and Angiogenesis to Delay Pulmonary Nodule Malignant Transformation

Screening for pulmonary nodules (PN) using low-dose CT has proven effective in reducing lung cancer (LC) mortality. However, current treatments relying on follow-up and surgical excision fail to fully address clinical needs. Pathological angiogenesis plays a pivotal role in supplying oxygen necessary for the progression of PN to LC. The interplay between hypoxia and angiogenesis establishes a vicious cycle, rendering anti-angiogenesis therapy alone insufficient to prevent PN to LC transformation. In traditional Chinese medicine (TCM), PN is referred to as "Feiji," which is mainly attributed to Qi and blood deficiency, correspondingly, the most commonly prescribed medicines are Astragalus membranaceus (Fisch.) Bge. var. mongholicus (Bge.) Hsiao (huang qi) (AR) and Angelica sinensis (Oliv.) Diels (dang gui) (ARS). Modern pharmacological studies have demonstrated that AR and ARS possess immune-enhancing, anti-tumor, anti-inflammatory, and anti-angiogenic properties. However, the precise mechanisms through which AR and ARS exert anti-angiogenic effects to delay PN progression to LC remain inadequately understood. This review explores the critical roles of hypoxia and angiogenesis in the transition from PN to LC. It emphasizes that, compared to therapies targeting angiogenic growth factors alone, AR, ARS, and their compound-based prescriptions offer additional benefits. These include ameliorating hypoxia by restoring blood composition, enhancing vascular structure, accelerating circulation, promoting vascular normalization, and blocking or inhibiting various pro-angiogenic expressions and receptor interactions. Collectively, these actions inhibit angiogenesis and delay the PN-to-LC transformation. Finally, this review summarizes recent advancements in related research, identifies existing limitations and gaps in knowledge, and proposes potential strategies and recommendations to address these challenges.

Astragali radix (Huangqi): a time-honored nourishing herbal medicine

Astragali radix (AR, namded Huangqi in Chinese) is the dried root of Astragalus membranaceus (Fisch.) Bge. var. mongholicus (Bge.) Hsiao or Astragalus membranaceus (Fisch.) Bge. As a widely used ethnomedicine, the biological activities of AR include immunomodulatory, anti-hyperglycemic, anti-oxidant, anti-aging, anti-inflammatory, anti-viral, anti-tumor, cardioprotective, and anti-diabetic effects, with minimum side effects. Currently, it is known that polysaccharides, saponins, and flavonoids are the indispensable components of AR. In this review, we will elaborate the research advancements of AR on ethnobotany, ethnopharmacological practices, phytochemicals, pharmacological activities, clinical uses, quality control, production developments, and toxicology. The information is expected to assist clinicians and scientists in developing useful therapeutic medicines with minimal systemic side effects.

Treatment of diabetic retinopathy with herbs for tonifying kidney and activating blood circulation: A review of pharmacological studies

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetic retinopathy (DR) is a prevalent microvascular complication of diabetes. Chinese medicine believes that kidney deficiency and blood stasis are significant pathogenesis of DR. A characteristic therapeutic approach for this pathogenesis is the kidney-tonifying and blood-activating method. By literature retrieval from several databases, we methodically summarized the commonly used kidney-tonifying and blood-activating herbs for treating DR, including Lycii Fructus, Rehmanniane Radix Praeparata, and Corni Fructus with the function of nourishing kidney; Salvia Miltiorrhizae Radix et Rhizoma with the function of enhancing blood circulation; Rehmanniae Radix with the function of nourishing kidney yin; and Astragali Radix with the function of tonifying qi. It has been demonstrated that these Chinese herbs described above, by tonifying the kidney and activating blood circulation, significantly improve the course of DR.

AIM OF THE STUDY

Through literature research, to gain a thorough comprehension of the pathogenesis of DR. Simultaneously, through the traditional application analysis, modern pharmacology research and network pharmacology analysis of kidney-tonifying and blood-activating herbs, to review the effectiveness and advantages of kidney-tonifying and blood-activating herbs in treating DR comprehensively.

MATERIALS AND METHODS

PubMed, the China National Knowledge Infrastructure (CNKI), and Wanfang Data were used to filter the most popular herbs for tonifying kidney and activating blood in the treatment of DR. The search terms were "diabetic retinopathy" and "tonifying kidney and activating blood". Mostly from 2000 to 2023. Network pharmacology was applied to examine the key active components and forecast the mechanisms of kidney-tonifying and blood-activating herbs in the treatment of DR.

RESULTS

Kidney deficiency and blood stasis are the pathogenesis of DR, and the pathogenesis is linked to oxidative stress, inflammation, hypoxia, and hyperglycemia. Scientific data and network pharmacology analysis have demonstrated the benefit of tonifying kidney and activating blood herbs in treating DR through several channels, multiple components, and multiple targets.

CONCLUSIONS

This review first presents useful information for subsequent research into the material foundation and pharmacodynamics of herbs for tonifying kidney and activating blood, and offers fresh insights into the treatment of DR.

Tert-butylhydroquinone protects the retina from oxidative stress in STZ-induced diabetic rats via the PI3K/Akt/eNOS pathway

This study aims to investigate whether tert-butylhydroquinone protects the retina from oxidative stress in STZ-induced experimental diabetic rats through the activation of phosphinositide 3-kinase (PI3K)/Akt/endothelial nitric oxide synthase (eNOS) pathway.In vitro, NO, reactive oxygen species(ROS), eNOS, p-eNOS Ser1179, Akt, p-Akt Ser473 and L-NAME protein expression was analyzed within rMC-1 cells cultivated within normal control(NC), high glucose (HG) and HG-containing tert-butyl hydroquinone (tBHQ) (5 μM) medium. We confirmed tBHQ's protection through administering inhibitors of PI3K and Akt. In vivo, tBHQ was administered at a ratio of 1% (w/w) to diabetic rats was induced through an STZ injection (65 mg/kg) for a 3-month period, and the retinal expression of eNOS, p-eNOS Ser1179, Akt, and p-Akt Ser473 proteins was measured using Western blotting (WB) assay. We also utilized the TUNEL kit for detecting retinal cell apoptosis. The changes of retinal morphology and visual function were measured by performing hematoxylin-eosin staining (HE staining) and electroretinograms. In vitro, ROS levels were increased in the high glucose group, NO levels were decreased, and the relative expression of Akt/p-Akt Ser473 and eNOs/p-eNOS Ser1179 was reduced. tBHQ abolished these changes, and these effects were suppressed by specific inhibitors. In vivo, tBHQ upregulated retinal protein expression in STZ-induced diabetic rats, reduced retinal apoptotic cell numbers, and partially prevented abnormalities in retinal function and structure caused by diabetes. tBHQ alleviates oxidative stress during diabetic retinopathy by upregulating the PI3K/Akt/eNOS pathway and partially restoring the structure and function of the retina. It may play a role in delaying vision loss caused by diabetic retinopathy.

VEGF-mediated angiogenesis in retinopathy of prematurity is co-regulated by miR-17-5p and miR-20a-5p

The microRNAs miR-17-5p and miR-20a-5p play important roles on angiogenesis; however, it is arguable whether they regulate the formation of retinal blood vessels in retinopathy of prematurity (ROP). We used a mouse model of oxygen-induced retinopathy (OIR) to simulate the development of retinas in mice suffering from ROP, and the expression levels of miR-20a-5p, miR-17-5p, hypoxia-inducible factor 1-alpha (HIF-1α), and vascular endothelial growth factor (VEGF) were measured by RT-qPCR and Western blotting. Cell proliferation, apoptosis, and angiogenesis in the OIR model mice were measured using MTT assays, flow cytometry, and Matrigel assays, respectively. The interaction between HIF-1α/VEGF and miR-20a-5p/miR-17-5p were further validated using dual-luciferase reporter assays, biotin-labeled RNA-pulldown, and RNA immunoprecipitation (RIP) assays. In our OIR model, retinal angiogenesis in the mice was associated with down-regulation of miR-20a-5p and miR-17-5p, as well as up-regulation of HIF-1α and VEGF. In addition, the miR-20a-5p and miR-17-5p inhibited cell proliferation and angiogenesis through regulating HIF-1α and VEGF in the retinal cells of the OIR model mice. Moreover, it was found that miR-20a-5p and miR-17-5p bind to HIF-1α and VEGF at the 3'UTR, and there was a combined effect between miR-20a-5p and miR-17-5p on the regulation of HIF-1α and VEGF. It is worth noting that miR-17-5p and miR-20a-5p can preferentially regulate HIF-1α, then act on VEGF, thereby affecting the angiogenesis associated with ROP.

Potential Effects of Nutraceuticals in Retinopathy of Prematurity

Retinopathy of prematurity (ROP), the most common cause of childhood blindness, is a hypoxia-induced eye disease characterized by retinal neovascularization. In the normal retina, a well-organized vascular network provides oxygen and nutrients as energy sources to maintain a normal visual function; however, it is disrupted when pathological angiogenesis is induced in ROP patients. Under hypoxia, inadequate oxygen and energy supply lead to oxidative stress and stimulate neovasculature formation as well as affecting the function of photoreceptors. In order to meet the metabolic needs in the developing retina, protection against abnormal vascular formation is one way to manage ROP. Although current treatments provide beneficial effects in reducing the severity of ROP, these invasive therapies may also induce life-long consequences such as systemic structural and functional complications as well as neurodevelopment disruption in the developing infants. Nutritional supplements for the newborns are a novel concept for restoring energy supply by protecting the retinal vasculature and may lead to better ROP management. Nutraceuticals are provided in a non-invasive manner without the developmental side effects associated with current treatments. These nutraceuticals have been investigated through various in vitro and in vivo methods and are indicated to protect retinal vasculature. Here, we reviewed and discussed how the use of these nutraceuticals may be beneficial in ROP prevention and management.