Erratum: Modulation of microglia by Wolfberry on the survival of retinal ganglion cells in a rat ocular hypertension model

Effects of Lycium barbarum L. Polysaccharides on Vascular Retinopathy: An Insight Review

Vascular retinopathy is a pathological change in the retina caused by ocular or systemic vascular diseases that can lead to blurred vision and the risk of blindness. Lycium barbarum polysaccharides (LBPs) are extracted from the fruit of traditional Chinese medicine, L. barbarum. They have strong biological activities, including immune regulation, antioxidation, and neuroprotection, and have been shown to improve vision in numerous studies. At present, there is no systematic literature review of LBPs on vascular retinal prevention and treatment. We review the structural characterization and extraction methods of LBPs, focus on the mechanism and pharmacokinetics of LBPs in improving vascular retinopathy, and discuss the future clinical application and lack of work. LBPs are involved in the regulation of VEGF, Rho/ROCK, PI3K/Akt/mTOR, Nrf2/HO-1, AGEs/RAGE signaling pathways, which can alleviate the occurrence and development of vascular retinal diseases in an inflammatory response, oxidative stress, apoptosis, autophagy, and neuroprotection. LBPs are mainly absorbed by the small intestine and stomach and excreted through urine and feces. Their low bioavailability in vivo has led to the development of novel dosage forms, including multicompartment delivery systems and scaffolds. Data from the literature confirm the medicinal potential of LBPs as a new direction for the prevention and complementary treatment of vascular retinopathy.

Lycium barbarum polysaccharides attenuate kidney injury in septic rats by regulating Keap1-Nrf2/ARE pathway

Lycium barbarum polysaccharides (LBP) are derived from Wolfberry and have antioxidant activities. This study aimed to evaluate the efficacy of LBP for kidney injury in a rat model of sepsis. Male rats were divided randomly to control group (Con), LPS group (LPS), ulinastatin group (ULI), low dose LBP group (LBP-1), middle dose LBP group (LBP-2) and high dose LBP group (LBP-3). After intraperitoneal injection of LPS (5 mg/kg) to make sepsis model (LPS group), 10,000 U/kg ulinastatin were given in ULI group, and 200, 400 and 800 mg/kg LBP was given in LBP-1, -2, -3 group, respectively. Serum IL-1β, IL-6, IL-8, TNF-α and NF-κB levels were measured by ELISA. Nrf2, Keap1, NF-κB, HO-1 and NQO1 expression levels were detected by PCR and Western blot analysis. We found that LBP decreased the levels of NF-κB and pro-inflammatory cytokines while attenuated kidney injury. In addition, LBP regulated Keap1-Nrf2/ARE signaling pathway in the kidney. In conclusion, LBP attenuates inflammation injury in the kidney via possible regulation of Keap1-Nrf2/ARE signaling.

Demystifying traditional Chinese medicines: Lycium barbarum as a model therapeutic

The practice of Traditional Chinese Medicine (TCM) focuses on holistic treatment of the body. This often includes preparation and application of medicinal herbs, either alone or in combination with other supplements. Lycium barbarum (LB), for example, is a commonly used herbal supplement in many Asian countries, being most well-known for improving kidney, liver, and eye health. It is also one of the most widely scientifically researched TCMs and a large body of literature is available describing its effects on various tissues and organ systems. In this perspective, we briefly expand upon how LB can be used as a model TCM in the systematic study of other herbal medicines, highlighting two of the primary barriers to their use in modern medicine worldwide.

Effect of the Notch signaling pathway on retinal ganglion cells and its neuroprotection in rats with acute ocular hypertension

AIM

To explore the effect of the Notch signaling pathway on retinal ganglion cells (RGCs) and optic nerve in rats with acute ocular hypertension (OH).

METHODS

Totally 48 Sprague-Dawley (SD) rats were included, among which 36 rats were selected to establish acute OH models. OH rats received a single intravitreal injection of 2 µL phosphate buffered solution (PBS) and another group of OH rats received a single intravitreal injection of 10 µmol/L γ-secretase inhibitor (DAPT). Quantitative real-time polymerase chain reaction (qPCR) and Western blot assay were adopted to determine the mRNA level of Notch and the protein levels of Notch, Bcl-2, Bax, caspase-3, and growth-associated protein 43 (GAP-43). The RGC apoptosis conditions were assessed by TUNEL staining.

RESULTS

The OH rats and PBS-injected rats had increased expression levels of Notch1, Bax, caspase-3, and GAP-43, decreased expression levels of Bcl-2, and increased RGC apoptosis, with severer macular edema and RGCs more loosely aligned, when compared with the normal rats. The DAPT-treated rats displayed increased expression levels of Notch1, Bax, caspase-3, and GAP-43, decreased expression levels of Bcl-2, and increased RGC apoptosis, in comparison with the OH rats and PBS-injected rats. RGCs were hardly observed and macular edema became severe in the DAPT-treated rat.

CONCLUSION

The Notch signaling pathway may suppress the apoptosis of retinal ganglion cells and enhances the regeneration of the damaged optic nerves in rats with acute OH.

Rational Basis for Nutraceuticals in the Treatment of Glaucoma

BACKGROUND

Glaucoma, the second leading cause of blindness worldwide, is a chronic optic neuropathy characterized by progressive retinal ganglion cell (RGC) axons degeneration and death. Primary open-angle glaucoma (OAG), the most common type, is often associated with increased intraocular pressure (IOP), however other factors have been recognized to partecipate to the patogenesis of the optic neuropathy. IOP-independent mechanisms that contribute to the glaucoma-related neurodegeneration include oxidative stress, excitotoxicity, neuroinflammation, and impaired ocular blood flow. The involvement of several and diverse factors is one of the reasons for the progression of glaucoma observed even under efficient IOP control with the currently available drugs.

METHODS

Current research and online content related to the potential of nutritional supplements for limiting retinal damage and improving RGC survival is reviewed.

RESULTS

Recent studies have suggested a link between dietary factors and glaucoma risk. Particularly, some nutrients have proven capable of lowering IOP, increase circulation to the optic nerve, modulate excitotoxicity and promote RGC survival. However, the lack of clinical trials limit their current therapeutic use. The appropriate use of nutraceuticals that may be able to modify the risk of glaucoma may provide insight into glaucoma pathogenesis and decrease the need for, and therefore the side effects from, conventional therapies.

CONCLUSION

The effects of nutrients with anti-oxidant and neuroprotective properties are of great interest and nutraceuticals may offer some therapeutic potential although a further rigorous evaluation of nutraceuticals in the treatment of glaucoma is needed to determine their safety and efficacy.

Effects of Lycium barbarum on the Visual System

Lycium barbarum (wolfberry, gogi berry, gouqizi, ) is one of the most widely used Chinese herbal medicines (CHMs) and is also one of the most scientifically studied. Indeed, the polysaccharide component of this berry (LBP) has been shown to have antioxidant, antiinflammatory, antiexcitotoxic, and antiapoptotic properties. These properties make it a particularly useful treatment option for the ocular environment. Although there are a handful of studies investigating the use of LBP to treat diseases affecting the lens, the vast majority of the published literature investigating LBP in the visual system focus on the retina. In this chapter, we have described what is currently understood concerning the effects of LBP treatment on various retinal diseases, including glaucoma, ischemia/reperfusion, age-related macular degeneration, retinitis pigmentosa, and diabetic retinopathy. We then describe the functions attributed to LBP using other cellular contexts to elucidate the full mechanisms this CHM utilizes in the retina. By making connections between what is known about the function of LBP in a variety of tissues and its function as a therapy for retinal degenerative diseases, we hope to further emphasize the continued use of this CHM in clinical medicine in addition to providing a platform for additional study.

Protective effects of fraction 4a of polysaccharides isolated from Lycium barbarum against KBrO3-induced renal damage in rats

LBP-4a exhibits protective effects on KBrO₃-induced renal damage, and the mechanism correlates with the increase of oxidation resistance in renal cells.

Natural compounds and retinal ganglion cell neuroprotection

Glaucoma, the second leading cause of blindness in the world, is a chronic optic neuropathy often associated with increased intraocular pressure and characterized by progressive retinal ganglion cell (RGC) axons degeneration and death leading to typical optic nerve head damage and distinctive visual field defects. Although the pathogenesis of glaucoma is still largely unknown, it is hypothesized that RCGs become damaged through various insults/mechanisms, including ischemia, oxidative stress, excitotoxicity, defective axonal transport, trophic factor withdrawal, and neuroinflammation. In this review, we summarize the potential benefits of several natural compounds for RGCs neuroprotection.

Lycium barbarum polysaccharides protected human retinal pigment epithelial cells against oxidative stress-induced apoptosis

AIM

To investigate the protective effect and its mechanism of lycium barbarum polysaccharides (LBP) against oxidative stress-induced apoptosis in human retinal pigment epithelial cells.

METHODS

ARPE-19 cells, a human retinal pigment epithelial cell lines, were exposed to different concentrations of H2O2 for 24h, then cell viability was measured by Cell Counting Kit-8 (CCK-8) assay to get the properly concentration of H2O2 which can induce half apoptosis of APRE-19. With different concentrations of LBP pretreatment, the ARPE-19 cells were then exposed to appropriate concentration of H2O2, cell apoptosis was detected by flow cytometric analysis. Expression levels of Bcl-2 and Bax were measured by real time quantitative polymerase chain reaction (RT-PCR) technique.

RSULTS

LBP significantly reduced the H2O2-induced ARPE-19 cells' apoptosis. LBP inhibited the H2O2-induced down-regulation of Bcl-2 and up-regulation of Bax.

CONCLUSION

LBP could protect ARPE-19 cells from H2O2-induced apoptosis. The Bcl-2 family had relationship with the protective effects of LBP.

Lycium barbarum polysaccharides protect rat liver from non-alcoholic steatohepatitis-induced injury

BACKGROUND

Lycium barbarum polysaccharides (LBPs) are antioxidant and neuroprotective derivative from Wolfberry. However, whether LBP has a protective effect in non-alcoholic steatohepatitis (NASH)-induced hepatic injury is still unknown.

OBJECTIVE

We aimed to study the possible hepatoprotective effects and mechanisms of LBP on a diet-induced NASH rat model.

METHODS AND DESIGN

In this study, female rats were fed a high-fat diet to induce NASH with or without an oral 1 mg kg(-1) LBP feeding daily for 8 weeks. After 8 weeks, blood serum and liver samples from each rat were subjected to histological analysis, biochemical and molecular measurements.

RESULTS

Compared with control rats, NASH rats showed typical NASH features including an increase in liver injury, lipid content, fibrosis, oxidative stress, inflammation and apoptosis. In contrast, NASH+LBP-co-treated rats showed (1) improved histology and free fatty acid levels; (2) re-balance of lipid metabolism; (3) reduction in profibrogenic factors through the TGF-β/SMAD pathway; (4) improved oxidative stress through cytochrome P450 2E1-dependent pathway; (5) reduction in hepatic pro-inflammatory mediators and chemokines production; and (6) amelioration of hepatic apoptosis through the p53-dependent intrinsic and extrinsic pathways. The preventive effects of LBP were partly modulated through the PI3K/Akt/FoxO1, LKB1/AMPK, JNK/c-Jun and MEK/ERK pathways and the downregulation of transcription factors in the liver, such as nuclear factor-κB and activator protein-1.

CONCLUSION

LBP is a novel hepatoprotective agent against NASH caused by abnormal liver metabolic functions.

Protection of retinal ganglion cells and retinal vasculature by Lycium barbarum polysaccharides in a mouse model of acute ocular hypertension

Acute ocular hypertension (AOH) is a condition found in acute glaucoma. The purpose of this study is to investigate the protective effect of Lycium barbarum polysaccharides (LBP) and its protective mechanisms in the AOH insult. LBP has been shown to exhibit neuroprotective effect in the chronic ocular hypertension (COH) experiments. AOH mouse model was induced in unilateral eye for one hour by introducing 90 mmHg ocular pressure. The animal was fed with LBP solution (1 mg/kg) or vehicle daily from 7 days before the AOH insult till sacrifice at either day 4 or day 7 post insult. The neuroprotective effects of LBP on retinal ganglion cells (RGCs) and blood-retinal-barrier (BRB) were evaluated. In control AOH retina, loss of RGCs, thinning of IRL thickness, increased IgG leakage, broken tight junctions, and decreased density of retinal blood vessels were observed. However, in LBP-treated AOH retina, there was less loss of RGCs with thinning of IRL thickness, IgG leakage, more continued structure of tight junctions associated with higher level of occludin protein and the recovery of the blood vessel density when compared with vehicle-treated AOH retina. Moreover, we found that LBP provides neuroprotection by down-regulating RAGE, ET-1, Aβ and AGE in the retina, as well as their related signaling pathways, which was related to inhibiting vascular damages and the neuronal degeneration in AOH insults. The present study suggests that LBP could prevent damage to RGCs from AOH-induced ischemic injury; furthermore, through its effects on blood vessel protection, LBP would also be a potential treatment for vascular-related retinopathy.

Neurodegeneration of the retina in mouse models of Alzheimer's disease: what can we learn from the retina?

Alzheimer's disease (AD) is an age-related progressive neurodegenerative disease commonly found among elderly. In addition to cognitive and behavioral deficits, vision abnormalities are prevalent in AD patients. Recent studies investigating retinal changes in AD double-transgenic mice have shown altered processing of amyloid precursor protein and accumulation of β-amyloid peptides in neurons of retinal ganglion cell layer (RGCL) and inner nuclear layer (INL). Apoptotic cells were also detected in the RGCL. Thus, the pathophysiological changes of retinas in AD patients are possibly resembled by AD transgenic models. The retina is a simple model of the brain in the sense that some pathological changes and therapeutic strategies from the retina may be observed or applicable to the brain. Furthermore, it is also possible to advance our understanding of pathological mechanisms in other retinal degenerative diseases. Therefore, studying AD-related retinal degeneration is a promising way for the investigation on (1) AD pathologies and therapies that would eventually benefit the brain and (2) cellular mechanisms in other retinal degenerations such as glaucoma and age-related macular degeneration. This review will highlight the efforts on retinal degenerative research using AD transgenic mouse models.

Effect of Lycium barbarum Polysaccharides on the expression of endothelin-1 and its receptors in an ocular hypertension model of rat glaucoma

Lycium barbarum, a traditional Chinese anti-aging herb, has been shown to protect retinal ganglion cells (RGCs) in a rat chronic ocular hypertension (COH) model. Here, we investigated the expression of endothelin-1 (ET-1), a strong vasoconstrictor, and its receptors, ETA and ETB, in the COH model and assessed the effects of Lycium barbarum on the ET-1 axis. Elevated intraocular pressure (IOP) was induced in the right eye of SD rats using argon laser photocoagulation. (1) The expression of ET-1, ETA and ETB in normal and COH retinas was studied. (2) Some COH rats were fed daily with Lycium barbarum Polysaccharides (LBP) using 1 mg/kg or phosphate-buffered saline (PBS) for 3 weeks (started 1 week before photocoagulation). The effects of LBP on the expression of ET-1 and its receptors, ETA and ETB, in COH retina were evaluated. A semi-quantitative analysis of staining intensity was used to evaluate the expression levels of ET-1, ETA and ETB in retinal vasculature. We found that (1) Under COH condition, the immunoreactivity of ET-1 was increased in retina associated with an increase of ETB receptor immunoreactivity and a decrease of ETA receptor immunoreactivity. (2) After feeding COH rats with LBP, the expression of ET-1 was decreased with an increase of ETA expression and a decrease of ETB expression in the retina, especially in RGCs. (3) By comparing the staining intensity in the vasculature of COH retina in LBP-fed group with PBS-fed group, there was a decrease in the expression of ET-1 and ETA and an increase in ETB. In summary, ET-1 expression was up-regulated in the retina in COH model. LBP could decrease the expression of ET-1 and modulate the expression of its receptors, ETA and ETB, under the condition of COH. The neuroprotective effect of LBP on RGCs might be related to its ability to regulate the ET-1-mediated biological effects on RGCs and retinal vasculature.