Potential therapeutic effects of crocin

Crocin, a natural bioactive compound derived from saffron (Crocus sativus) and other Crocus genera, has gained significant attention recently due to its potential therapeutic properties. The multifaceted nature of crocin's biological effects has piqued the interest of researchers and health enthusiasts, prompting further investigations into its mechanisms of action and therapeutic applications. This review article comprehensively explores the emerging evidence supporting crocin's role as a promising ally in protecting against metabolic disorders. The review covers the molecular mechanisms underlying crocin's beneficial effects and highlights its potential applications in preventing and treating diverse pathological conditions. Understanding the mechanisms through which crocin exerts its protective effects could advance scientific knowledge and offer potential avenues for developing novel therapeutic interventions. As we uncover the potential of crocin as a valuable ally in the fight against disorders, it becomes evident that nature's palette holds remarkable solutions for enhancing our health.

Molecular pathways in experimental glaucoma models

Glaucoma is a complex and progressive disease that primarily affects the optic nerve axons, leading to irreversible vision loss. Although the exact molecular mechanisms underlying glaucoma pathogenesis are not fully understood, it is believed that except increased intraocular pressure, a combination of genetic and environmental factors play a role in the development of the disease. Animal models have been widely used in the study of glaucoma, allowing researchers to better understand the underlying mechanisms of the disease and test potential treatments. Several molecular pathways have been implicated in the pathogenesis of glaucoma, including oxidative stress, inflammation, and excitotoxic-induced neurodegeneration. This review summarizes the most important knowledge about molecular mechanisms involved in the glaucoma development. Although much research has been done to better understand the molecular mechanisms underlying this disease, there is still much to be learned to develop effective treatments and prevent vision loss in those affected by glaucoma.

Combination Therapy with N-Acetylserotonin and Aflibercept Activated the Akt/Nrf2 Pathway to Inhibit Apoptosis and Oxidative Stress in Rats with Retinal Ischemia-Reperfusion Injury

PURPOSE

N-acetylserotonin (NAS) can reduce retinal ischemia-reperfusion injury (RIRI) by inhibiting the TLR4/NF-κB/NLRP3 signaling pathway. Aflibercept is an anti-VEGF drug used to treat a variety of eye diseases. This study was performed to investigate the effect of combination therapy with N-acetylserotonin and aflibercept on RIRI and its mechanism.

METHODS

The RIRI model was established by elevating the intraocular pressure. H&E staining was used to observe the pathological changes in the retinal tissue. Cell apoptosis was evaluated by TUNEL. The expression of cleaved caspase-3 in the retina was detected by immunofluorescence and western blotting. The levels of SOD, GSH-Px, and MDA in retinal tissue were measured by ELISA. The protein expression of cytoplasmic Nrf2, nuclear Nrf2, HO-1, Akt, and p-Akt was determined by western blotting.

RESULTS

The results showed that combination therapy with NAS and aflibercept significantly alleviated retinal histopathological damage, decreased retinal thickness (from 335.49 ± 30.50 µm to 226.16 ± 17.20 µm, p < 0.001) and the rate of retinal apoptosis (from 28.27 ± 0.39% to 7.87 ± 0.19%, p < 0.001), and downregulated protein expression (from 2.42 ± 0.03 to 1.39 ± 0.03, p < 0.001) and positive expression (from 31.88 ± 0.52 to 25.36 ± 0.58, p < 0.001) of cleaved caspase-3. In addition, combination therapy with NAS and aflibercept also upregulated the levels of SOD (from 20.31 ± 0.18 to 29.66 ± 0.83, p < 0.001) and GSH-Px (from 13.62 ± 0.36 to 19.31 ± 0.82, p < 0.001) and downregulated the level of MDA (from 0.51 ± 0.01 to 0.41 ± 0.01, p < 0.001) to inhibit oxidative stress. Finally, combination therapy with NAS and aflibercept increased the protein expression of cytoplasmic Nrf2 (from 0.10 ± 0.002 to 0.85 ± 0.01, p < 0.001), nuclear Nrf2 (from 0.43 ± 0.01 to 0.88 ± 0.04, p < 0.001), and HO-1 (from 0.45 ± 0.03 to 0.91 ± 0.04, p < 0.001) and the p-Akt/Akt ratio (from 0.45 ± 0.02 to 0.81 ± 0.07, p < 0.001).

CONCLUSIONS

Overall, combination therapy with NAS and aflibercept attenuated RIRI, and its mechanism may be related to inhibiting apoptosis and oxidative stress and activating the Akt/Nrf2 pathway.

Crocin Inhibits Orbital Fibroblasts Fibrosis in Thyroid-Associated Ophthalmopathy

PURPOSE

To investigate the role of Crocin on proliferation, fibrosis, and migration of orbital fibroblasts, as well as the possible signaling pathway.

METHODS

Immunofluorescence assay was performed to detect the expression of fibroblast marker proteins vimentin cytokeratin, desmin, and S-100. The quantity of 5‑ethynyl‑2'‑deoxyuridine-positive cells in orbital fibroblast was analyzed. Quantitative real-time PCR and western blots were performed to evaluate the expression level of fibrosis-related marker including alpha-smooth muscle actin, connective-tissue growth factor, collagen 1A1, and fibronectin. Scratch wound assays were performed to assess wound widths of orbital fibroblast. The expression and phosphorylation of extracellular signal-regulated kinase/signal transducer and activator of transcription 3 were evaluated using western blots. The phosphorylation of smad2 and smad3 was evaluated using immunofluorescence assay.

RESULTS

Crocin treatment reduced 5‑ethynyl‑2'‑deoxyuridine-positive cells, indicating inhibitory effect on orbital fibroblast proliferation. The expression levels of alpha-smooth muscle actin, connective-tissue growth factor, collagen 1A1 and fibronectin were declined in Crocin treatment. Delayed wound closures were observed in Crocin treatment. Furthermore, Crocin did not affect the expression of extracellular signal-regulated kinase and signal transducer and activator of transcription 3, but weakened extracellular signal-regulated kinase and signal transducer and activator of transcription 3 phosphorylation in orbital fibroblast. The phosphorylation of smad2 and smad3 was attenuated by Crocin as well.

CONCLUSION

In conclusion, Crocin inhibits the phosphorylation of extracellular signal-regulated kinase and signal transducer and activator of transcription 3, contributing to the inhibitory effect on proliferation, fibrosis, and migration of orbital fibroblast, suggesting that Crocin has potential to be a novel therapeutic candidate for thyroid-associated ophthalmopathy treatment.

Gardenia yellow pigment: Extraction methods, biological activities, current trends, and future prospects

Food coloring plays a vital role in influencing consumers' food choices, imparting vibrant and appealing colors to various food and beverage products. Synthetic food colorants have been the most commonly used coloring agents in the food industry. However, concerns about potential health issues related to synthetic colorants, coupled with increasing consumer demands for food safety and health, have led food manufacturers to explore natural alternatives. Natural pigments not only offer a wide range of colors to food products but also exhibit beneficial bioactive properties. Gardenia yellow pigment is a water-soluble natural pigment with various biological activities, widely present in gardenia fruits. Therefore, this paper aims to delve into Gardenia Yellow Pigment, highlighting its significance as a food colorant. Firstly, a thorough understanding and exploration of various methods for obtaining gardenia yellow pigment. Subsequently, the potential functionality of gardenia yellow pigment was elaborated, especially its excellent antioxidant and neuroprotective properties. Finally, the widespread application trend of gardenia yellow pigment in the food industry was explored, as well as the challenges faced by the future development of gardenia yellow pigment in the field of food and health. Some feasible solutions were proposed, providing valuable references and insights for researchers, food industry professionals, and policy makers.

Crocin alleviates neurotoxicity induced by bupivacaine in SH-SY5Y cells with inhibition of PI3K/AKT signaling

BACKGROUND

Bupivacaine, a common local anesthetic, can cause neurotoxicity and permanent neurological disorders. Crocin has been widely reported as a potential neuroprotective agent in neural injury models.

OBJECTIVE

The aim of this study was to investigate the role and regulatory mechanism of crocin underlying bupivacaine-induced neurotoxicity.

METHOD

Human neuroblastoma SH-SY5Y cells were treated with bupivacaine and/or crocin for 24 h, followed by detecting cell viability using 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay. The effect of crocin or bupivacaine on SH-SY5Y cell proliferation was measured by Ki67 immunofluorescence assay. The levels of apoptosis-related proteins and the markers in the PI3K/Akt signaling pathway were examined using western blot analysis. The activities of caspase 3, catalase (CAT), superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione peroxidase (GSH-Px) were tested using respective commercial assay kits. Flow cytometry analysis was executed for detecting SH-SY5Y cell apoptosis.

RESULT

Crocin attenuated bupivacaine-induced neurotoxicity in SH-SY5Y cells. Meanwhile, crocin inhibited SH-SY5Y cell apoptosis induced by bupivacaine via repressing the activity of caspase-3, reducing Bax expression, and elevating Bcl-2 expression. Moreover, crocin mitigated oxidative stress in SH-SY5Y cells by increasing the content of CAT, SOD, GSH-Px and reducing the content of MDA. Additionally, crocin protected against bupivacaine-induced dephosphorylation of Akt and GSK-3β. The protective effects of crocin against bupivacaine-induced neurotoxicity in SH-SY5Y cells were counteracted by the Akt inhibitor.

CONCLUSION

These results suggested that crocin may exert a neuroprotective function by promoting cell proliferation and suppressing apoptosis and oxidative stress in SH-SY5Y cells. Thus, crocin might become a promising drug for the treatment of bupivacaine-induced neurotoxicity.

Herbal and Natural Treatments for the Management of the Glaucoma: An Update

Glaucoma causes the degeneration of the retinal ganglion cells (RGCs) and their axons, inducing a tissue reshaping that affects both the retina and the optic nerve head. Glaucoma care especially focuses on reducing intraocular pressure, a significant risk factor for progressive damage to the optic nerve. The use of natural treatments, such as herbs, vitamins, and minerals, is becoming increasingly popular today. While plants are a rich source of novel biologically active compounds, only a small percentage of them have been phytochemically examined and evaluated for their medicinal potential. It is necessary for eye care professionals to inform their glaucoma patients about the therapy, protection, and efficacy of commonly used herbal medicines, considering the widespread use of herbal medicines. The purpose of this review is to examine evidence related to the most widely used herbal medicines for the management and treatment of glaucoma, to better understand the potential benefits of these natural compounds as supplementary therapy.

Various Forms of Programmed Cell Death Are Concurrently Activated in the Population of Retinal Ganglion Cells after Ischemia and Reperfusion

Retinal ischemia-reperfusion (IR)-which ultimately results in retinal ganglion cell (RGC) death-is a common cause of visual impairment and blindness worldwide. IR results in various types of programmed cell death (PCD), which are of particular importance since they can be prevented by inhibiting the activity of their corresponding signaling cascades. To study the PCD pathways in ischemic RGCs, we used a mouse model of retinal IR and a variety of approaches including RNA-seq analysis, knockout animals, and animals treated with an iron chelator. In our RNA-seq analysis, we utilized RGCs isolated from retinas 24 h after IR. In ischemic RGCs, we found increased expression of many genes that regulate apoptosis, necroptosis, pyroptosis, oxytosis/ferroptosis, and parthanatos. Our data indicate that genetic ablation of death receptors protects RGCs from IR. We showed that the signaling cascades regulating ferrous iron (Fe²⁺) metabolism undergo significant changes in ischemic RGCs, leading to retinal damage after IR. This data suggests that the activation of death receptors and increased Fe²⁺ production in ischemic RGCs promote the simultaneous activation of apoptosis, necroptosis, pyroptosis, oxytosis/ferroptosis, and parthanatos pathways. Thus, a therapy is needed that concurrently regulates the activity of the multiple PCD pathways to reduce RGC death after IR.

Natural products: protective effects against ischemia-induced retinal injury

Ischemic retinal damage, a common condition associated with retinal vascular occlusion, glaucoma, diabetic retinopathy, and other eye diseases, threatens the vision of millions of people worldwide. It triggers excessive inflammation, oxidative stress, apoptosis, and vascular dysfunction, leading to the loss and death of retinal ganglion cells. Unfortunately, minority drugs are available for treating retinal ischemic injury diseases, and their safety are limited. Therefore, there is an urgent need to develop more effective treatments for ischemic retinal damage. Natural compounds have been reported to have antioxidant, anti-inflammatory, and antiapoptotic properties that can be used to treat ischemic retinal damage. In addition, many natural compounds have been shown to exhibit biological functions and pharmacological properties relevant to the treatment of cellular and tissue damage. This article reviews the neuroprotective mechanisms of natural compounds involve treating ischemic retinal injury. These natural compounds may serve as treatments for ischemia-induced retinal diseases.

Review on potential effects of traditional Chinese medicine on glaucoma

ETHNIC PHARMACOLOGICAL RELEVANCE

Glaucoma is the second most common blindness in the world, which seriously affects the life quality of patients. Traditional Chinese Medicines (TCM), are important plant materials, widely used for ocular disease all over the world. With the help of modern ophthalmic detection technology, TCM has gradually become an important content in the field of ophthalmology, characterized by more targets and lower toxicity.

AIM OF THIS REVIEW

This review presents an overview of the pathogenesis of glaucoma in both modern and traditional medicines, and summarizes the therapeutic effect of TCM on glaucoma including their formula, crude drugs and active components, and also the application of acupuncture.

METHODS

A collection and collation of relevant scientific articles from different scientific databases was performed regarding TCM and its application on glaucoma. The therapeutic effects of TCM were summarized and analyzed according to the existing experimental and clinical researches, while the GSE26299 database were employed to screen bioinformatics analysis of glaucoma based on the GEO database chip.

RESULTS

There were many positive signs showing that TCM could increase the survival rate of retinal ganglion cells, which may be related to its regulation of microcirculation, oxidative stress, and the immune system. Hence, TCM plays an active role in treating glaucoma. In addition, the bioinformatics analysis predicted that the pathogenesis of glaucoma might be related to p53, MAPK, NF-κB signal, as well as other pathways by KEGG analysis, and the results from bioinformatics analysis predicted that PIK3R6, FGF1, and TYRP1 etc. CONCLUSION: TCM exerts definite effects on preventing and treating ocular disease. It could alleviate and treat glaucoma in various ways. The differentiation syndrome should thus be taken as the basis to propose appropriate treatment options of TCM making their application on glaucoma more popular.

Multiple types of programmed necrosis such as necroptosis, pyroptosis, oxytosis/ferroptosis, and parthanatos contribute simultaneously to retinal damage after ischemia-reperfusion

Ischemia-reperfusion (IR) injury is implicated in a large array of pathological conditions in the retina. Increasing experimental evidence suggests that programmed necrosis makes a significant contribution to inflammation and retinal damage triggered by IR. Since there are many types of programmed necrosis, it is important to identify those involved in retinal IR to determine the correct treatment. To this end, we used a mouse model of retinal IR and a variety of approaches including RNA-seq data analysis. Our RNA-seq data revealed the rapid development of ischemic pathology in the retina during the first 24 h after reperfusion. We found that at least four types of programmed necrosis including necroptosis, pyroptosis, oxytosis/ferroptosis, and parthanatos are simultaneously involved in retinal IR. Our data suggest that the high activity of the TNF pathway at the early stage of retinal IR leads to early activation of necroptosis while significant activity of other types of programmed necrosis appears later. Our results indicate that TNF, glutamate, and ferrous iron generated by Steap3 may be key players concurrently triggering at least necroptosis, oxytosis/ferroptosis, and parthanatos in ischemic retinal ganglion cells (RGCs). Thus, multiple signaling cascades involved in programmed necrosis should be synchronously targeted for therapeutic purposes to treat retinal IR.

Glial cell response to constant low light exposure in rat retina

To study the macroglia and microglia and the immune role in long-time light exposure in rat eyes, we performed glial cell characterization along the time-course of retinal degeneration induced by chronic exposure to low-intensity light. Animals were exposed to light for periods of 2, 4, 6, or 8 days, and the retinal glial response was evaluated by immunohistochemistry, western blot and real-time reverse transcription polymerase chain reaction. Retinal cells presented an increased expression of the macroglia marker GFAP, as well as increased mRNA levels of microglia markers Iba1 and CD68 after 6 days. Also, at this time-point, we found a higher number of Iba1-positive cells in the outer nuclear layer area; moreover, these cells showed the characteristic activated-microglia morphology. The expression levels of immune mediators TNF, IL-6, and chemokines CX3CR1 and CCL2 were also significantly increased after 6 days. All the events of glial activation occurred after 5-6 days of constant light exposure, when the number of photoreceptor cells has already decreased significantly. Herein, we demonstrated that glial and immune activation are secondary to neurodegeneration; in this scenario, our results suggest that photoreceptor death is an early event that occurs independently of glial-derived immune responses.

Crocins for Ischemic Stroke: A Review of Current Evidence

Crocins (CRs) and the related active constituents derived from Crocus sativus L. (Saffron) have demonstrated protective effects against cerebral ischemia and ischemic stroke, with various bioactivities including neuroprotection, anti-neuroinflammation, antioxidant, and cardiovascular protection. Among CRs, crocin (CR) has been shown to act on multiple mechanisms and signaling pathways involved in ischemic stroke, including mitochondrial apoptosis, nuclear factor kappa light chain enhancer of B cells pathway, S100 calcium-binding protein B, interleukin-6 and vascular endothelial growth factor-A. CR is generally safe and well-tolerated. Pharmacokinetic studies indicate that CR has poor bioavailability and needs to convert to crocetin (CC) in order to cross the blood-brain barrier. Clinical studies have shown the efficacy of saffron and CR in treating various conditions, including metabolic syndrome, depression, Alzheimer’s disease, and coronary artery disease. There is evidence supporting CR as a treatment for ischemic stroke, although further studies are needed to confirm their efficacy and safety in clinical settings.

The Functional Vision Restorative Effect of Crocin via the BDNF-TrkB Pathway: An In Vivo Study

Abnormal dislocation of cone opsin protein affects the sensitivity function of photoreceptors and results in depressed central vision. Nutraceutical therapy is needed to restore the residual function of photoreceptors. Crocin is a natural substance for retinal health. However, its effect on the restoration of functional vision and its underlying mechanisms have not been fully studied. This study analyzed the restorative effect of crocin on residual functional vision in vivo in a mouse model. High-energy light-evoked photoreceptor dysfunction was confirmed by M opsin dislocation in the retina accompanied by a loss of functional vision. Crocin treatment significantly increased brain-derived neurotrophic factor (BDNF) protein in retinas, thus contributing to the re-localization of the M opsin protein, restoration of the visual acuity (VA), and high spatial frequency-characterized visual contrast sensitivity function (VCSF). In contrast, such effects were significantly reversed after the washout period. Additionally, the restorative effect of crocin on functional vision and M opsin re-localization can be reversed and blocked by synchronous injection of a tropomyosin receptor kinase B (TrkB) receptor antagonist (ANA-12). This study demonstrated the major functional vision-rescuing or restoring effect of crocin in vivo by modulating M opsin location plasticity and increasing the capacity of the residual photoreceptor function through the BDNF-TrkB receptor pathway.

Neuronal differentiation of mesenchymal stem cells by polyvinyl alcohol/Gelatin/crocin and beta-carotene

BACKGROUND

Nerve tissues are important in coordinating the motions and movements of the body. Nerve tissue repair and regeneration is a slow process that might take a long time and cost a lot of money. As a result, tissue engineering was employed to treat nerve tissue lesions. The aim of this study was to investigate the proliferation of C6 cells and human mesenchymal stem cells derived bone marrow (hBMMSCs) differentiate into neuronal-like cells on the polyvinyl alcohol/gelatin/crocin (PVA/Gel/Cro) nanofiber scaffolds in vitro.

METHODS

PVA/Gel scaffolds containing crocin in three concentrations (1%, 3%, and 5%) were prepared by the electrospinning method. The human bone marrow-derived mesenchymal stem cells (hBMSCs) differentiation on the PVA/Gel/Cro 5% that induced by beta-carotene (βC), was analyzed during 10 days. Morphology of differentiated cells on the scaffolds was taken by scanning electron microscope (SEM). The expression of the neural cell markers was studied by quantitative reverse transcription- polymerase chain reaction (qRT-PCR) and immunocytochemistry (ICC).

RESULTS

MTT results of C6 cells culture on the scaffolds showed that proliferation and metabolic activity on PVA/Gel scaffold containing crocin 5% (PVA/Gel/Cro 5%) are significantly more than the other concentrations (P = 0.01). MSC differentiation to nerve-like cells was approved by MAP-2 expression at the mRNA level and NESTIN and MAP-2 at the protein level.

CONCLUSIONS

These results suggested that PVA/Gel/Cro 5% and βC could lead to hBMSCs differentiation to neural cells.

Crocin as a vision supplement

Crocin is a natural ingredient of saffron (Crocus sativus L.) flower that has shown potential for application as a supplement in eye health and preserving vision. Crocin has been examined for its potential to treat various eye diseases such as glaucoma, macular dystrophies, diabetic retinopathy, and age-related macular degeneration. This review briefly discusses the role of crocin in different eye diseases. The underlying pathophysiological pathways involved in the effect of crocin on ophthalmic diseases are also reviewed. Preclinical evidence shows the cytoprotective, antioxidative, anti-inflammatory, and blood-flow enhancing effects of crocin in retinal tissue. Crocin also affects the retinal pathologies by activating PI3K/Akt and inhibiting NF-κB signalling pathways. Clinical evidence suggests that crocin improves outcomes in patients with retinal degenerations, retinal dystrophies, and glaucoma. Overall, crocin can be suggested as a potential vision supplement in healthy populations and patients with eye diseases. However, more clinical studies with larger sample sizes and longer follow-up durations are needed to confirm the current evidence.

Treatment of Glaucoma with Natural Products and Their Mechanism of Action: An Update

Glaucoma is one of the leading causes of irreversible blindness. It is generally caused by increased intraocular pressure, which results in damage of the optic nerve and retinal ganglion cells, ultimately leading to visual field dysfunction. However, even with the use of intraocular pressure-lowering eye drops, the disease still progresses in some patients. In addition to mechanical and vascular dysfunctions of the eye, oxidative stress, neuroinflammation and excitotoxicity have also been implicated in the pathogenesis of glaucoma. Hence, the use of natural products with antioxidant and anti-inflammatory properties may represent an alternative approach for glaucoma treatment. The present review highlights recent preclinical and clinical studies on various natural products shown to possess neuroprotective properties for retinal ganglion cells, which thereby may be effective in the treatment of glaucoma. Intraocular pressure can be reduced by baicalein, forskolin, marijuana, ginsenoside, resveratrol and hesperidin. Alternatively, Ginkgo biloba, Lycium barbarum, Diospyros kaki, Tripterygium wilfordii, saffron, curcumin, caffeine, anthocyanin, coenzyme Q10 and vitamins B3 and D have shown neuroprotective effects on retinal ganglion cells via various mechanisms, especially antioxidant, anti-inflammatory and anti-apoptosis mechanisms. Extensive studies are still required in the future to ensure natural products' efficacy and safety to serve as an alternative therapy for glaucoma.

Crocins: A comprehensive review of structural characteristics, pharmacokinetics and therapeutic effects

Crocins, as a kind of water-soluble carotenoid pigment, are a series of ester compounds formed from crocetin and gentibiose or glucose, and mainly distributed among Crocus sativus L. (CSL), Gardenia jasminoides Ellis. (GJE). Crocins exhibit a wide range of pharmacological effects on neurodegeneration, cardiovascular disease, cerebrovascular disease, depression, liver disease, arthritis, tumor, diabetes, etc. This review systematically discussed the pharmacologic study of crocins in the aspect of structural characteristic and pharmacokinetics, and summarized the mechanism of treating disease. It summarized the abundant research of crocins from 1984 to 2020 based on the above aspects, which provide a reference for the deeply development and application of crocins.

Anti-inflammatory activities of Gardenia jasminoides extracts in retinal pigment epithelial cells and zebrafish embryos

Age-related macular degeneration (AMD) is the most common cause of visual impairment in developed countries. Inflammation serves a critical role in the pathogenesis of AMD. Gardenia jasminoides is found in several regions of China and is traditionally used as an organic yellow dye but has also been widely used as a therapeutic agent in numerous diseases, including inflammation, depression, hepatic and vascular disorders, which may reflect the variability of functional compounds that are present in Gardenia jasminoides extracts (GJE). To investigate the therapeutic potential of GJE for AMD, ARPE-19 cells were treated with lipopolysaccharide (LPS) or LPS plus GJE. GJE significantly decreased LPS-induced expression of proinflammatory cytokines, including IL-1β, IL-6 and TNF-α. In the in vivo study, GJE inhibited CuSO4-induced migration of primitive macrophages to the lateral line in zebrafish embryos. GJE also attenuated expression of cytokines (IL-1β, IL-6 and TNF-α), NFKB activating protein (nkap) and TLR4 in ARPE-19 cells. The results of the present study demonstrated the anti-inflammatory potential of GJE in vitro and in vivo, and suggested GJE as a therapeutic candidate for AMD.

Pharmacological Effects of Saffron and its Constituents in Ocular Disorders from in vitro Studies to Clinical Trials: A Systematic Review

Introduction:

Some medicinal plants have shown promising therapeutic potential for the management of the diseases. We aimed to systematically review the literature wherein the therapeutic effects of saffron have been studied on eye disorders.

Methods

A systematic literature search was performed in PubMed, Scopus, Web of Science, Google scholar and other databases using eye disorders and saffron as key terms. No strict inclusion criteria were defined, and almost all clinical studies, as well as in vivo and in vitro studies were included. The reported data in each study were extracted and then qualitatively described.

Results

Finally, 78 articles were found but only 29 relevant articles were included. Nine articles were clinical trials and 20 articles were studies conducted on cellular and molecular aspects of saffron on eye disorders. According to the included studies, crocin prevented the pro-inflammatory response in retinal cells and decreased glucose levels in diabetic mice. Also, crocetin prevented retinal degeneration and saffron protected photoreceptors from light-induced damage in retinal cells. Saffron also improved visual function in age-related macular edema and decreased intraocular pressure in patients with glaucoma. In addition, it was shown that crocin can improve best corrected visual acuity and decrease central macular thickness in patients with diabetic maculopathy.

Conclusion

The results of this review indicated that saffron and its main ingredients such as crocin could be a potential candidate for the treatment of ocular disease especially eye inflammation; however, further clinical studies are needed to confirm such efficiency.

Natural Products: Evidence for Neuroprotection to Be Exploited in Glaucoma

Glaucoma, a leading cause of irreversible blindness worldwide, is an optic neuropathy characterized by the progressive death of retinal ganglion cells (RGCs). Elevated intraocular pressure (IOP) is recognized as the main risk factor. Despite effective IOP-lowering therapies, the disease progresses in a significant number of patients. Therefore, alternative IOP-independent strategies aiming at halting or delaying RGC degeneration is the current therapeutic challenge for glaucoma management. Here, we review the literature on the neuroprotective activities, and the underlying mechanisms, of natural compounds and dietary supplements in experimental and clinical glaucoma.

Comparative assessment of immunomodulatory, proliferative, and antioxidant activities of crocin and crocetin on mesenchymal stem cells

Saffron (Crocus sativus L) is a well-known spice with active pharmacologic components including crocin, crocetin, safranal, and picrocrocin. Similar to crocin/crocetin, mesenchymal stem cells (MSCs) have been shown to display immunomodulatory and antioxidant properties, which could be beneficial in treatment of various diseases. In the current study, we have evaluated the effects of crocin and crocetin on the functions of MSCs. We used the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay to evaluate MSCs proliferation, and flow cytometry assay to measure the percentage of apoptotic MSCs and Tregs populations. Furthermore, we used the real-time polymerase chain reaction method to quantify messenger RNA (mRNA) expression of inflammatory and anti-inflammatory cytokines. Antioxidant assay was employed to quantify antioxidant parameters including nitric oxide and malondialdehyde levels besides superoxide dismutase activity. Our findings indicated that both crocin and crocetin at low concentrations (2.5 and 5 µM) exhibited significant effects on increasing MSCs viability and on protecting them against apoptosis-induced death. Furthermore, crocin and crocetin at low concentrations (2.5 and 5 µM) displayed a better antioxidant function. Moreover, increased Treg population was observed at lower doses. In addition, crocin/crocetin at low concentrations caused an elevation in mRNA expression of anti-inflammatory cytokines (transforming growth factor-β, interleukin-10 [IL-10], and IL-4), while at higher doses (25 and 50 µM) they led to lowering inflammatory cytokines (IL-1β, IL-6, IL-17, and interferon gamma). Altogether, both crocin and crocetin at lower concentrations exhibited more efficacies on MSCs with a better effect toward crocin. It seems that crocin and crocetin may be considered as complementary treatments for the patients who undergo MSCs transplantation.

Novel Neuroprotective Potential of Crocin in Neurodegenerative Disorders: An Illustrated Mechanistic Review

Neurodegenerative disorders are characterized by mitochondrial dysfunction and subsequently oxidative stress, inflammation, and apoptosis that contribute to neuronal cytotoxicity and degeneration. Recent studies reported that crocin, a carotenoid chemical compound common in crocus and gardenia flowers, has protective effects in neurodegenerative disorders due to its anti-oxidative, anti-inflammatory, and anti-apoptotic properties in the nervous system. This article reviews the new experimental, clinical, and pharmacological studies on the neuroprotective properties of crocin and its potential mechanisms to modulate metabolic oxidative stress and inflammation in neurodegenerative disorders.

Therapeutic potentials of crocin in medication of neurological disorders

Neurological sicknesses are serious, multifactorial, debilitating disorders that may cause neurodegeneration. Neuroprotection is the protection of the structure and capacity of neurons from affronts emerging from cell injuries instigated by an assortment of specialists or neurodegenerative diseases. Various neurodegenerative diseases, including Alzheimer's, Parkinson's, and epilepsy, afflict many people worldwide, with increasing age representing the leading risk factor. Crocin is a natural carotenoid compound which was found to have therapeutic potentials in the management of the neurological disease. In this review, we focused on the restorative capabilities of Crocin as a neuroprotective agent. The general neuroprotective impact and the various conceivable basic components identified with Crocin have been examined. In light of the substantial proof indicating the neuro-pharmacological viability of Crocin to different exploratory standards, it is concluded that Crocin exerts direct antioxidant, antiapoptotic and anti-inflammatory activities by multiple signaling pathways. Besides, Crocin was found to elevate dopamine level in the brain during the experimental model of Parkinson's disease. Thus, this compound has been demonstrated to be a promising option for the treatment of neurodegenerative diseases, with few adverse effects. It ought to be further considered as a potential contender for neuro-therapeutics, concentrating on the mechanistic and clinical evidence for its effects.

The effect of crocin on memory, hippocampal acetylcholine level, and apoptosis in a rat model of cerebral ischemia

Although the memory- improving effect of crocin has been suggested by previous evidences, the association between this effect and hippocampal acetylcholine (Ach) level and apoptosis is not well investigated. This study aimed to determine the protective effects of crocin on memory, hippocampal Ach level, and apoptosis in a rat model of cerebral ischemia. Male Wistar rats were divided into sham group received saline, and other 3 groups underwent 4-vessel occlusion brain ischemia (4VOI), received oral administration of either saline or crocin in doses of 30 mg/day and 60 mg/day for 7 days. Outcomes were memory, determined by radial eight-arm maze (RAM) task and Morris water maze (MWM) test, Ach release in the dorsal hippocampus (evaluated by microdialysis-HPLC) and apoptosis (investigated by TUNEL assay). 4VOI impaired memory reduced dorsal hippocampus Ach level, and induced apoptosis. Crocin, significantly improved the memory (F = 343.20; P < 0.001 for RAM error choices and F = 182.5; P < 0.0001 for MWM), increased Ach level (F = 115.1; P < 0.001) and prevented hippocampal neuronal apoptosis (W = 183.50; P < 0.001) as compared statistically by ANOVA test. Crocin can be suggested as a promising therapy for ischemic cerebrovascular accidents by its memory preserving, Ach-increasing, and neuroprotective effects.

Neuroprotective Strategies for Retinal Ganglion Cell Degeneration: Current Status and Challenges Ahead

The retinal ganglion cells (RGCs) are the output cells of the retina into the brain. In mammals, these cells are not able to regenerate their axons after optic nerve injury, leaving the patients with optic neuropathies with permanent visual loss. An effective RGCs-directed therapy could provide a beneficial effect to prevent the progression of the disease. Axonal injury leads to the functional loss of RGCs and subsequently induces neuronal death, and axonal regeneration would be essential to restore the neuronal connectivity, and to reestablish the function of the visual system. The manipulation of several intrinsic and extrinsic factors has been proposed in order to stimulate axonal regeneration and functional repairing of axonal connections in the visual pathway. However, there is a missing point in the process since, until now, there is no therapeutic strategy directed to promote axonal regeneration of RGCs as a therapeutic approach for optic neuropathies.

Cardioprotective Effect of Olive Oil Against Ischemia Reperfusion-induced Cardiac Arrhythmia in Isolated Diabetic Rat Heart

Background

Olive oil is rich in monounsaturated fatty acids and has been reported for a variety of beneficial cardiovascular effects, including blood pressure lowering, anti-platelet, anti-diabetic, and anti-inflammatory effects. Diabetes is a major risk factor for cardiac dysfunctions, and olive oil prevents diabetes-induced adverse myocardial remodeling.

Objective

The study aimed to evaluate the effects of olive oil against streptozotocin-induced cardiac dysfunction in animal models of diabetes and ischemia and reperfusion (I/R)-induced cardiac arrhythmias.

Methods

Diabetes was induced in male rats with a single intraperitoneal injection of streptozotocin (60 mg/kg i.p), rats were treated for five, 15, or 56 days with olive oil (1 ml/kg p.o). Control animals received saline. Blood glucose and body weight were monitored every two weeks. At the end of the treatment, rats were sacrificed and hearts were isolated for mounting on Langedorff’s apparatus. The effect of olive oil on oxidative stress and histopathological changes in the cardiac tissues were studied.

Results

The initial blood glucose and body weight were not significantly different in the control and olive-treated animals. Streptozotocin (60 mg/kg i.p) caused a significant increase in the blood glucose of animals as compared to saline-treated animals. The control, saline-treated diabetic animals exhibited a 100% incidence of I/R-induced ventricular fibrillation, which was reduced to 0% with olive oil treatment. The protective effects of olive oil were evident after 15 and 56 days of treatment. Diltiazem, a calcium channel blocker (1 µm/L) showed similar results and protected the I/R-induced cardiac disorders. The cardiac tissues isolated from diabetic rats exhibited marked pathological changes in the cardiomyocytes, including decreased glutathione (GSH) and increased oxidative stress (malondialdehyde; MDA). Pretreatment of animals with olive oil (1 ml/kg p.o) increased GSH and decreased MDA levels. Olive oil also improved the diabetic-induced histopathological changes in the cardiomyocytes.

Conclusion

Olive oil possesses cardiac protective properties against I/R-induced cardiac arrhythmias in rats. It attenuated oxidative stress and diabetes-induced histopathological changes in cardiac tissues. The observed cardiac protectiveness of olive oil in the present investigation may be related to its antioxidant potential.

Beneficial effects of saffron (Crocus sativus L.) in ocular pathologies, particularly neurodegenerative retinal diseases

Saffron (Crocus sativus L.) has been traditionally used in food preparation and as a medicinal plant. It currently has numerous therapeutic properties attributed to it, such as protection against ischemia, as well as anticonvulsant, antidepressant, anxiolytic, hypolipidemic, anti-atherogenic, anti-hypertensive, antidiabetic, and anti-cancer properties. In addition, saffron has remarkable beneficial properties, such as anti-apoptotic, anti-inflammatory and antioxidant activities, due to its main metabolites, among which crocin and crocetin stand out. Furthermore, increasing evidence underwrites the possible neuroprotective role of the main bioactive saffron constituents in neurodegenerative diseases, such as Parkinson’s and Alzheimer’s diseases, both in experimental models and in clinical studies in patients. Currently, saffron supplementation is being tested for ocular neurodegenerative pathologies, such as diabetic retinopathy, retinitis pigmentosa, age-related macular degeneration and glaucoma, among others, and shows beneficial effects. The present article provides a comprehensive and up to date report of the investigations on the beneficial effects of saffron extracts on the main neurodegenerative ocular pathologies and other ocular diseases. This review showed that saffron extracts could be considered promising therapeutic agents to help in the treatment of ocular neurodegenerative diseases.

Cytoprotective effect of crocin and trans-resveratrol on photodamaged primary human retinal pigment epithelial cells

PURPOSE

Light-induced damage to retinal pigment epithelium during pars plana vitrectomy remains a hot topic in ophthalmology. Improvements in technology led to a change of light sources, selective filters, and shorter light exposure time. Currently, there is no satisfying solution to the problem. The aim of the study was to investigate the cytoprotective effects of crocin and resveratrol on light-induced damage to primary human retinal pigment epithelial cells in vitro.

METHODS

Primary human retinal pigment epithelial cells were exposed to light analogous to the illumination during pars plana vitrectomy. To evaluate the cytoprotective effects and potential toxicity of resveratrol and crocin, human retinal pigment epithelial cells were incubated with varying concentrations of both before 3-[4,5-dimethylthiazol-2-yl] tetrazolium bromide (MTT) viability assay. Furthermore, glutathione levels were measured to investigate synergistic antioxidant potential. Apoptosis of human retinal pigment epithelial cells was determined by a nucleosome detection enzyme-linked immunosorbent assay.

RESULTS

Crocin and resveratrol improved cell viability in photodamaged human retinal pigment epithelial cells significantly from 40.65 ± 21.99% in illuminated human retinal pigment epithelial cells and reached a peak viability of 85.64 ± 11.37% in crocin and resveratrol pretreated cells (for all: p < 0.001). In line, the combination of the supplements increased glutathione levels significantly from 39.35 ± 21.96% to 80.74 ± 10.32% (p = 0.017). No toxic effects were detected (p > 0.99). However, no change in apoptosis rates could be observed following pretreatment with crocin and resveratrol (p > 0.99).

CONCLUSION

Crocin and trans-resveratrol revealed cytoprotective effects on human retinal pigment epithelial cells supporting both supplement's development as potential perioperative treatments in light-induced retinal pigment epithelial damage.

Therapeutic Strategies for Attenuation of Retinal Ganglion Cell Injury in Optic Neuropathies: Concepts in Translational Research and Therapeutic Implications

Retinal ganglion cell (RGC) death is the central and irreversible endpoint of optic neuropathies. Current management of optic neuropathies and glaucoma focuses on intraocular pressure-lowering treatment which is insufficient. As such, patients are effectively condemned to irreversible visual impairment. This review summarizes experimental treatments targeting RGCs over the last decade. In particular, we examine the various treatment modalities and determine their viability and limitations in translation to clinical practice. Experimental RGC treatment can be divided into (1) cell replacement therapy, (2) neuroprotection, and (3) gene therapy. For cell replacement therapy, difficulties remain in successfully integrating transplanted RGCs from various sources into the complex neural network of the human retina. However, there is significant potential for achieving full visual restoration with this technique. Neuroprotective strategies, in the form of pharmacological agents, nutritional supplementation, and neurotrophic factors, are viable strategies with encouraging results from preliminary noncomparative interventional case series. It is important to note, however, that most published studies are focused on glaucoma, with few treating optic neuropathies of other etiologies. Gene therapy, through the use of viral vectors, has shown promising results in clinical trials, particularly for diseases with specific genetic mutations like Leber's hereditary optic neuropathy. This treatment technique can be further extended to nonhereditary diseases, through transfer of genes promoting cell survival and neuroprotection. Crucially though, for gene therapy, teratogenicity remains a significant issue in translation to clinical practice.

Regional Expression of Act-MMP3 Contributes to the Selective Loss of Neurons in Ganglion Cell Layers following Acute Retinal ischemia/Reperfusion Injury

Purpose: Evidences suggest that during ischemia/reperfusion events, neuronal loss in ganglion cell layers (GCLs) occurs initially in the peripheral retinae followed by the central. However, which key molecule or factor mediates this selective loss needs elucidation. In the present study, we detected the regional expression of active matrix metalloproteinase 3 (Act-MMP3) in the central and peripheral rat retinae following acute retinal ischemia/reperfusion (RI/R) injury and explored the effects and mechanisms of this regional expression on the selective neuronal loss in GCLs.Methods: QPCR and Western Blotting were used to detect the expression of Act-MMP3 in the central part and peripheral part of the adult rat retinae. Immunofluorescence and double immunofluorescence were used to assess the number of NeuN-positive cells in the GCLs and Iba-1+CD 68-positive cells were determined. Additionally, the Linear-regression analysis was performed to test the correlation between the ODV of Act-MMP3 and the neuronal loss in the GCLs/Iba-1+CD 68 positive cells in retinae.Results: An evident up-regulation of active matrix metalloproteinase 3 (Act-MMP3) in peripheral retinae preceded to that in central region following acute RI/R. We found Act-MMP3 up-regulation to be associated with the selective neuronal loss in GCLs (central: r = 0.7566, p < .0001, r² = 0.5724; peripheral: r = 0.8241, p < .0001, r² = 0.6792). Suppressing Act-MMP3 ameliorated the selective neuronal loss in GCLs following acute RI/R. Furthermore, the activation of microglia in the peripheral retinae also preceded to that in the central and was found to be correlated with the regional expression of Act-MMP3 (Central: r = 0.8540, p < .0001, r² = 0.7294; Peripheral: r = 0.7820, p < .0001, r² = 0.6116). Suppressing Act-MMP3 ameliorated the microglia regional activation following acute RI/R.Conclusion: The regional expression of Act-MMP3 in the rat retinae may contribute to the selective neuronal loss in GCLs and microglia regional activation in acute RI/R.

Prophylactic neuroprotective propensity of Crocin, a carotenoid against rotenone induced neurotoxicity in mice: behavioural and biochemical evidence

Previously we have demonstrated the potential neuroprotective propensity of saffron and Crocin (CR) employing a Drosophila model of Parkinsonism. Rotenone (ROT) has been extensively used as a model neurotoxin to induce Parkinson's disease (PD) like symptoms in mice. In the present study, as a proof of concept we evaluated the efficacy of CR prophylaxis (25 mg/ kg bw/d, 7d) to attenuate ROT(0.5 mg/Kg bw/d,7d) -induced neurotoxic effects in male mice focussing on neurobehavioural assessments and biochemical determinants in the striatum. CR prophylaxis significantly alleviated ROT-induced behavioural alterations such as increased anxiety, diminished exploratory behaviour, decreased motor co-ordination, and grip strength. Concomitantly, we evidenced diminution of oxidative stress markers, enhanced levels of antioxidant enzyme and mitochondrial enzyme function in the striatal region. Further, varying degree of restoration of cholinergic function, dopamine and α-synuclein levels were discernible suggesting the possible mechanism/s of action of CR in this model. Based on our earlier data in flies and in worm model, we propose its use as an adjuvant therapeutic agent in oxidative stress-mediated neurodegenerative conditions such as PD.

Interaction of saffron carotenoids with catalase: in vitro, in vivo and molecular docking studies

The effects of saffron carotenoids, crocetin (Crt) and crocin (Cro) on the structure, function and kinetics of catalase (CAT) were investigated. Both Crt and Cro quenched the fluorescence emission of CAT through the dynamic mechanism, but Crt (Ksv= 8.1 × 10⁴ mol^-1) was more effective than Cro (Ksv= 0.6 × 10⁴ mol^-1) at 300 °K. The UV-vis and circular dichroism spectra showed conformational changes of CAT in the presence of both carotenoids, but with different degrees. Kinetic studies showed strong inhibition of CAT by Crt, while, different concentrations of Cro showed different effects. Our in vitro data showed that Crt treatment significantly (p = 0.002) reduced the CAT activity in MCF-7, up to 24 h. The in vivo results showed that both Crt and Cro significantly increased the CAT activity in the tumor (p = 0.000 for both), and liver (p = 0.000 and p = 0.026 for Crt and Cro, respectively) tissues of 4T1-induced breast cancer in BALB/c mice, after 4 weeks of treatment. These findings are consistent with the binding, thermodynamic and molecular docking data. In conclusion, Crt and Cro with some differences in the structure affect CAT structure, function and activity, but in a slightly different manner.Communicated by Ramaswamy H. Sarma.

Neuroprotective and Anti-Inflammatory Effects of a Hydrophilic Saffron Extract in a Model of Glaucoma

Glaucoma is a neurodegenerative disease characterized by the loss of retinal ganglion cells (RGCs). An increase in the intraocular pressure is the principal risk factor for such loss, but controlling this pressure does not always prevent glaucomatous damage. Activation of immune cells resident in the retina (microglia) may contribute to RGC death. Thus, a substance with anti-inflammatory activity may protect against RGC degeneration. This study investigated the neuroprotective and anti-inflammatory effects of a hydrophilic saffron extract standardized to 3% crocin content in a mouse model of unilateral, laser-induced ocular hypertension (OHT). Treatment with saffron extract decreased microglion numbers and morphological signs of their activation, including soma size and process retraction, both in OHT and in contralateral eyes. Saffron extract treatment also partially reversed OHT-induced down-regulation of P2RY12. In addition, the extract prevented retinal ganglion cell death in OHT eyes. Oral administration of saffron extract was able to decrease the neuroinflammation associated with increased intraocular pressure, preventing retinal ganglion cell death. Our findings indicate that saffron extract may exert a protective effect in glaucomatous pathology.

Modulating Expression of Thioredoxin Interacting Protein (TXNIP) Prevents Secondary Damage and Preserves Visual Function in a Mouse Model of Ischemia/Reperfusion

Retinal neurodegeneration, an early characteristic of several blinding diseases, triggers glial activation, resulting in inflammation, secondary damage and visual impairment. Treatments that aim only at neuroprotection have failed clinically. Here, we examine the impact of modulating thioredoxin interacting protein (TXNIP) to the inflammatory secondary damage and visual impairment in a model of ischemia/reperfusion (IR). Wild type (WT) and TXNIP knockout (TKO) mice underwent IR injury by increasing intraocular pressure for 40 min, followed by reperfusion. An additional group of WT mice received intravitreal TXNIP-antisense oligomers (ASO, 100 µg/2 µL) 2 days post IR injury. Activation of Müller glial cells, apoptosis and expression of inflammasome markers and visual function were assessed. IR injury triggered early TXNIP mRNA expression that persisted for 14 days and was localized within activated Müller cells in WT-IR, compared to sham controls. Exposure of Müller cells to hypoxia-reoxygenation injury triggered endoplasmic reticulum (ER) stress markers and inflammasome activation in WT cells, but not from TKO cells. Secondary damage was evident by the significant increase in the number of occluded acellular capillaries and visual impairment in IR-WT mice but not in IR-TKO. Intervention with TXNIP-ASO prevented ischemia-induced glial activation and neuro-vascular degeneration, and improved visual function compared to untreated WT. Targeting TXNIP expression may offer an effective approach in the prevention of secondary damage associated with retinal neurodegenerative diseases.

The protective effects of Crocin on testopathy in fat-fed and streptozotocin-treated diabetic rats: An experimental study

Background

Male hypogonadism is associated with type II diabetes mellitus due to testicular dysfunction. Medicinal plants have received considerable attention for the management of diabetes and its complications.

Objective

The aim of present study was to evaluate the anti-diabetic and protective influence of Crocin on testopathy in diabetic rats.

Materials and Methods

In this experimental study, type II of diabetes mellitus was induced by high-fat diet and low dose of streptozotocin. Male Wistar rats (8 weeks, 150–200 gr, 18 rats; n= 6 per group) were divided into a control group (standard diet), diabetic group (streptozotocin+high-fat diet), and treatment group (High-fat diet+streptozotocin+Crocin at 20 mg/kg/day, i.p. for 60 days). After 60 days, animals were euthanized, testis and epididymis were dissected, and weights of testes and sperm count were analyzed. Hematoxylin-eosin-stained was done for histopathological examination. Blood samples were collected for the assessment of serum glucose and cholesterol.

Results

High-fat diet and streptozotocin significantly increased the serum glucose and cholesterol levels as compared to the control group (p≤ 0. 001). Moreover, there was a significant decrease in the weight of right (p= 0.008) and left testes (p≤ 0. 001) and also the total sperm count (p= 0.023) in the diabetic group compared with the control group. Current results also identified that type II diabetes mellitus induced degeneration in the morphology of seminiferous tubules. Application of Crocin could significantly decrease serum glucose and cholesterol levels (p= 0.003). Furthermore, Crocin treatment significantly increased the weight of the right (p= 0.026) and left (p= 0.014) testes and total sperm count (p= 0.000). Also, Crocin could attenuate the pathological changes of the testes in the treatment group.

Conclusion

Present findings concluded that Crocin treatment improved diabetic testopathy and impairment of seminiferous tubules induced by high-fat diet and streptozotocin.

Protective effects of hypercapnic acidosis on Ischemia-reperfusion-induced retinal injury

Ischemia–reperfusion (I/R) injury is associated with numerous retinal diseases, such as diabetic retinopathy, acute glaucoma, and other vascular retinopathies. Hypercapnic acidosis (HCA) has a protective effect on lung, myocardial, and central nervous system ischemic injury models. However, no study has evaluated its protective effects in an experimental retinal I/R injury model. In this study, retinal I/R injury was induced in Sprague Dawley rats by elevating the intraocular pressure to 110 mmHg for 60 minutes. HCA was induced before and after the injury. After 24 hours, the terminal dUTP nick end labeling assay was performed. Moreover, the ratios of cleaved caspase-3/total caspase-3, phosphorylated IκB/IκB, and phosphorylated p38 were measured through Western blotting. After 7 days, the rats’ aqueous humor was analyzed. In addition, electroretinography and retinal thickness measurement were performed in the rats. Moreover, the retinal neural cell line RGC-5 was exposed to 500 μM H₂O₂ for 24 hours to induce a sustained oxidative stress in vitro. The effects of HCA were evaluated by comparing oxidative stress, MAPK signals, NF-κB signals, survival rates, and apoptosis rates in the RGC-5 cells before and after H₂O₂ exposure. We further investigated whether the potent I/R-protective heat shock protein (HSP) 32 contribute to protective effects of HCA. Our results indicated that HCA has protective effects against retinal I/R injury both in vivo and in vitro, at multiple levels, including antiapoptotic, anti-inflammatory, antioxidative, and functional retinal cell protection. Further research clarifying the role of HCA in retinal I/R injury prevention and treatment is warranted.

The Role of Endogenous Neuroprotective Mechanisms in the Prevention of Retinal Ganglion Cells Degeneration

Retinal neurons are not able to undergo spontaneous regeneration in response to damage. A variety of stressors, i.e., UV radiation, high temperature, ischemia, allergens, and others, induce reactive oxygen species production, resulting in consecutive alteration of stress-response gene expression and finally can lead to cell apoptosis. Neurons have developed their own endogenous cellular protective systems. Some of them are preventing cell death and others are allowing functional recovery after injury. The high efficiency of these mechanisms is crucial for cell survival. In this review we focus on the contribution of the most recently studied endogenous neuroprotective factors involved in retinal ganglion cell (RGC) survival, among which, neurotrophic factors and their signaling pathways, processes regulating the redox status, and different pathways regulating cell death are the most important. Additionally, we summarize currently ongoing clinical trials for therapies for RGC degeneration and optic neuropathies, including glaucoma. Knowledge of the endogenous cellular protective mechanisms may help in the development of effective therapies and potential novel therapeutic targets in order to achieve progress in the treatment of retinal and optic nerve diseases.

Saffron therapy for the treatment of mild/moderate age-related macular degeneration: a randomised clinical trial

PURPOSE

To assess the efficacy and safety of oral saffron, a natural antioxidant, in treating mild/moderate age-related macular degeneration (AMD).

METHODS

Randomised, double-blinded, placebo-controlled crossover trial of 100 adults (> 50 years) with mild/moderate AMD and vision > 20/70 Snellen equivalent in at least one eye. Exclusion criteria included confounding visual lesions, or significant gastrointestinal disease impairing absorption. Participants were given oral saffron supplementation (20 mg/day) for 3 months or placebo for 3 months, followed by crossover for 3 months. Participants already consuming Age-Related Eye Diseases Study (AREDS) supplements or equivalent maintained these. Primary outcomes included changes in best-corrected visual acuity (BCVA) and changes in multifocal electroretinogram (mfERG) response density and latency. Secondary outcomes included safety outcomes and changes in mfERG and BCVA amongst participants on AREDS supplements.

RESULTS

Mean BCVA improved 0.69 letters (p = 0.001) and mean-pooled mfERG latency reduced 0.17 ms (p = 0.04) on saffron compared to placebo. Amongst participants on AREDS supplements, mean BCVA improved 0.73 letters p = 0.006) and mean-pooled mfERG response density improved 2.8% (p = 0.038). There was no significant difference in adverse event occurrence (p > 0.10).

CONCLUSION

Saffron supplementation modestly improved visual function in participants with AMD, including those using AREDS supplements. Given the chronic nature of AMD, longer-term supplementation may produce greater benefits.

Nutritional supplementation in the treatment of glaucoma: A systematic review

Current treatment strategies for glaucoma are limited to halting disease progression and do not restore lost visual function. Intraocular pressure is the main risk factor for glaucoma, and intraocular pressure-lowering treatment remains the mainstay of glaucoma treatment, but even successful intraocular pressure reduction does not stop the progression of glaucoma in all patients. We review the literature to determine whether nutritional interventions intended to prevent or delay the progression of glaucoma could prove to be a valuable addition to the mainstay of glaucoma therapy. A total of 33 intervention trials were included in this review, including 21 randomized controlled trials. These suggest that flavonoids exert a beneficial effect in glaucoma, particularly in terms of improving ocular blood flow and potentially slowing progression of visual field loss. In addition, supplements containing forskolin have consistently demonstrated the capacity to reduce intraocular pressure beyond the levels achieved with traditional therapy alone; however, despite the strong theoretical rationale and initial clinical evidence for the beneficial effect of dietary supplementation as an adjunct therapy for glaucoma, the evidence is not conclusive. More and better quality research is required to evaluate the role of nutritional supplementation in glaucoma.

Down-regulated miR-187 promotes oxidative stress-induced retinal cell apoptosis through P2X7 receptor

Several microRNAs (miRNAs) expressed in the retina were confirmed to involve in retinal cell apoptosis, which was closely linked with the development of retinal diseases. Our previous studies have confirmed a vital role of miR-187 in retinal cells apoptosis. The aim of this study was to further elucidate the precise role of miR-187 and its probable mechanisms in RGC-5 cells apoptosis. The cellular oxidative stress status was assessed by reactive oxygen species (ROS) production and malondialdehyde (MDA) level. Our results showed that the elevated pressure, glutamate and H₂O₂-induced oxidative stress in RGC-5 cells was accompanied by a decrease in miR-187 expression and an increase in P2X7R expression. However, overexpression of miR-187 reversed this activation of oxidative stress in RGC-5 cells. Moreover, we also revealed that miR-187 inhibited the oxidative stress-induced apoptosis of RGC-5 cells through negative regulating P2X7R, probably through interacting with the 3'UTR of P2X7R. Finally, we confirmed that the forced miR-187 expression alleviated oxidative stress injury in retina tissues of rat models with chronic ocular hypertension. Our data demonstrated that miR-187/P2X7R signaling was involved in retinal cell apoptosis, at least in part, through activating oxidative stress.

Crocin prevents platelet‑derived growth factor BB‑induced vascular smooth muscle cells proliferation and phenotypic switch

The phenotypic switch of vascular smooth muscle cells (VSMCs) is a major initiating factor for atherosclerotic cardiovascular diseases. Platelet-derived growth factor-BB (PDGF-BB) initiates a number of biological processes that contribute to VSMC proliferation and phenotypic switch. Crocin, a component of saffron, has been reported to inhibit atheromatous plaque formation. However, the effects of crocin on PDGF-BB-induced VSMC proliferation and phenotypic switch remain unclear. The aim of the present study was to investigate the role of crocin on PDGF-BB-induced VSMCs proliferation and phenotypic switch and its underlying mechanisms. Cell proliferation and markers of VSMCs phenotypic switch were measured using a Cell Counting Kit-8 assay and western blot analysis, respectively. The signaling pathways involved in the effects of crocin on VSMCs were validated by western blot analysis with or without the use of specific pathway inhibitors. Crocin significantly inhibited PDGF-BB-induced VSMCs proliferation compared with the PDGF-BB only group (P<0.05). In addition, crocin significantly abrogated the PDGF-BB-induced increase in contractile protein α-smooth muscle actin, calponin and decrease in synthetic proteins osteopontin (OPN) in a concentration dependent manner (P<0.05). In addition, crocin slowed PDGF-BB-induced Janus kinase (JAK)-signal transducer and activator of transcription 3 (STAT3) and extracellular signal-regulated kinase (ERK)/Kruppel-like factor 4 (KLF4) signaling activation in VSMCs. By applying the JAK inhibitor (AG490) and ERK1/2 inhibitor (U0126), the results suggested that the crocin inhibited PDGF-BB-induced VSMCs phenotypic switch through the JAK/STAT3 and ERK/KLF4 signaling pathways. These results suggested that crocin may effectively prevent PDGF-BB-induced VSMCs proliferation and phenotypic switch and may be a promising candidate for the therapy of atherosclerotic cardiovascular diseases.

Preventive effects of crocin on neuronal damages induced by D-galactose through AGEs and oxidative stress in human neuroblastoma cells (SH-SY5Y)

Objective

D-galactose (D-gal) is well-known agent to induce aging process. In the present study, we selected crocin, the main constituent of Crocus sativus L. (saffron), against D-gal-induced cytotoxicity in human neuroblastoma SH-SY5Y cells.

Methods

Pretreated cells with crocin (25–500 μM, 24 h) were exposed to D-gal (25–400 mM, 48 h). The MTT assay was used for determination cell viability. Dichlorofluorescin diacetate assay (DCF-DA) and senescence associated β-galactosidase staining assay (SA-β-gal) were used to evaluate the generation of reactive oxygen species and beta-galactosidase as an aging marker, respectively. Also advanced glycation end products (AGEs) expression which is known as the main mechanism of age-related diseases was measured by western blot analysis.

Results

The findings of our study showed that treatment of cells with D-gal (25–400 mM) for 48h decreased cell viability concentration dependency. Reactive oxygen species (ROS) levels which are known as main factors in age-related diseases increased from 100 ± 8% in control group to 132 ± 22% in D-gal (200 mM) treated cells for 48h. The cytotoxic effects of D-gal decreased with 24h crocin pretreatment of cells. The cell viability at concentrations of 100 μM, 200 μM and 500 μM increased and ROS production decreased at concentrations of 200 and 500 μM to 111.5 ± 6% and 108 ± 5%, respectively. Also lysosomal biomarker of aging and carboxymethyl lysine (CML) expression as an AGE protein, significantly increased in D-gal 200 mM group after 48h incubation compare to control group. Pretreatment of SHSY-5Y cells with crocin (500 μM) before adding D-gal significantly reduced aging marker and CML formation.

Conclusion

Treatment of SH-SY5Y cells with crocin before adding of D-gal restored aging effects of D-gal concentration dependency. These findings indicate that crocin has potent anti-aging effects through inhibition of AGEs and ROS production.

SIRT1 exhibits antioxidative effects in HT22 cells induced by tert-butyl alcohol

Tertiary butyl alcohol (TBA) is a principal metabolite of methyl tertiary-butyl ether (MTBE), a common pollutant worldwide in the ground or underground water, which is found to produce nervous system damage. Nevertheless, few data regarding the effects of TBA has been reported. Studies indicated that oxidative stress plays a pivotal role in MTBE neurotoxic mechanism. Sirtuin 1 (SIRT1) has been reported to exert a neuroprotective effect on various neurologic diseases via resistance to oxidative stress by deacetylating its substrates. In this study, we examined levels of oxidative stress after exposure to TBA for 6 h in HT22 cells and HT22 cells with SIRT1 silencing (transfected with SIRT1 siRNA) or high expression (preconditioned with agonists SRT1720). We found that TBA activated oxidative stress by increasing generation of intracellular reactive oxygen species (ROS), malondialdehyde (MDA) and Oxidized glutathione (GSSG), and decreasing contents of superoxide dismutase (SOD) and glutathione reductase (GSH). In additional, levels of TBA-induced oxidative stress were aggravated when SIRT1 silenced but alleviated when SIRT1 enhanced. Our study indicated that SIRT1 mitigated oxidative stress induced by TBA.

The Protective Effects of αB-Crystallin on Ischemia-Reperfusion Injury in the Rat Retina

To investigate whether αB-crystallin protects against acute retinal ischemic reperfusion injury (I/R) and elucidate the potential antioxidant mechanisms. Retinal I/R injury was made by elevating the intraocular pressure (IOP) 110 mmHg for 60 min, and αB-crystallin (1 × 10⁻⁵ g/L) or vehicle solution was administered intravitreously immediately after I/R injury. The animal was sacrificed 24 h, 1 w, and 1 m after the I/R injury. The retina damage was detected by hematoxylin and eosin (HE) staining and electroretinography (ERG). The level of malondialdehyde (MDA), nitric oxide (NO), and the total superoxide dismutase (T-SOD) was determined. An immunohistochemical study was performed to detect the activation of inducible nitric oxide synthase (iNOS) and NF- (nuclear factor-) kappaB (NF-κB) p65. The decrease of retinal thickness and the number of retinal ganglion cells (RGCs) can be suppressed by αB-crystallin. And the amplitudes of a- and b-wave were remarkably greater without αB-crystallin. Similarly, αB-crystallin also significantly decreased the level of MDA and NO and enhanced the activities of T-SOD. The positive expression of iNOS and NF-kappaB p65 was obviously reduced while treated with αB-crystallin. αB-crystallin can inhibit the expression of NF-κB and its antioxidative effect to protect the retina from I/R injury.