Lycium barbarum L. and Salvia miltiorrhiza Bunge protect retinal pigment epithelial cells through endoplasmic reticulum stress

Lycium barbarum L. and Salvia miltiorrhiza Bunge extract ameliorates retinitis pigmentosa in rd10 Mice by affecting endoplasmic reticulum stress

ETHNOPHARMACOLOGICAL RELEVANCE

Lycium barbarum L. and Salvia miltiorrhiza Bunge (Gouqi and Danshen, LS) have led to their inclusion in the pharmacopoeia and healthcare systems of numerous countries globally. Traditional herbs known as LS are used in China to treat retinitis pigmentosa (RP). However, the mechanism is not clear.

AIM OF THE STUDY

This study is to investigate the mechanism by which LS improves RP using rd10 mice as a model.

MATERIALS AND METHODS

LS extract was used to treat the rd10 mice for four weeks. Fundus photographs, optical coherence tomography, electroretinography, histopathological examination, TUNEL apoptosis assay, digital PCR analysis, western blotting, and immunofluorescence double staining were performed.

RESULTS

The outer nuclear layer (ONL) thickness of the retina was significantly increased by the LS extract, improving atrophy, and both the ONL and the retinal pigment epithelium (RPE) layer were visible. Following treatment with LS extract, there was a notable increase in the magnitudes of ERG a- and b-waves in the retina, along with a significant reduction in the quantity of TUNEL-positive cells. Additionally, LS extract significantly reduced the levels of ER stress-related factors in rd10 mice. The results of immunofluorescence double staining further confirm that LS extract inhibits the GRP78/PERK/ATF4/CHOP pathway.

CONCLUSION

In this study, the protective effects of LS extract on the retina were uncovered, suggesting that its mechanism could involve decreasing retinal cell apoptosis through the inhibition of the ER stress pathway.

Comparative evaluation of four Lycium barbarum cultivars on NaIO3-induced retinal degeneration mice via multivariate statistical analysis

ETHNOPHARMACOLOGICAL RELEVANCE

The fruit of Lycium barbarum L. (goji berry) is a traditional Chinese medicine and is often used to improve vision. While various goji cultivars may differentially treat retinal degeneration, however their comparative effectiveness remains unclear.

AIM OF THE STUDY

To evaluate the protective effects of four goji cultivars on NaIO3-induced retinal degeneration mouse model and identify the most therapeutically potent cultivar.

MATERIALS AND METHODS

The principal compounds in the extracts of four goji cultivars were characterized by UPLC-Q-TOF/MS. A retinal degeneration mouse model was established via NaIO3 injection. Dark-light transition and TUNEL assays were used to assess visual function and retinal apoptosis. The levels of antioxidative, inflammatory, and angiogenic markers in serums and eyeballs were measured. Hierarchical cluster analysis, principal component analysis and partial least squares-discriminant analysis were used to objectively compare the treatment responses.

RESULTS

Sixteen compounds were identified in goji berry extracts. All goji berry extracts could reverse NaIO3-induced visual impairment, retinal damage and apoptosis. The samples from the cultivar of Ningqi No.1 significantly modulated oxidative stress, inflammation, and vascular endothelial growth factor levels, which are more effectively than the other cultivars based on integrated multivariate profiling.

CONCLUSION

Ningqi No.1 demonstrated a stronger protective effect on mouse retina than other goji cultivars, and is a potential variety for further research on the treatment of retinal degeneration.

Integrated network pharmacology and experimental validation to explore the potential pharmacological mechanism of Qihuang Granule and its main ingredients in regulating ferroptosis in AMD

BACKGROUND

Qihuang Granule (QHG) is a traditional prescription  that has exhibited potential in safeguarding against age-related maculopathy (AMD). Salvia miltiorrhiza (SM) and Fructus lycii (FL) are the main components of QHG. Ferroptosis, a newly discovered, iron-dependent, regulated cell death pathway, have been implicated in the pathogenesis of AMD. This study delves into the intricate mechanism by which SM/FL and QHG confer protection against AMD by modulating the ferroptosis pathway, employing a combination of network pharmacology and experimental validation.

METHODS

Bioactive compounds and potential targets of SM and FL were gathered from databases such as TCMSP, GeneCard, OMIM, and FerrDb, along with AMD-related genes and key genes responsible for ferroptosis regulation. Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis and protein-protein interaction (PPI) network were performed to discover the potential mechanism. The construction of an interaction network involving AMD, ferroptosis, SM/FL potential target genes was facilitated by the STRING database and realized using Cytoscape software. Subsequent validation was accomplished through molecular docking and in vitro cell experiments.

RESULTS

Noteworthy active compounds including quercetin, tanshinone IIA, luteolin, cryptotanshinone, and hub targets such as HIF-1α, EGFR, IL6, and VEGFA were identified. KEGG enrichment unveiled the HIF-1 signalling pathway as profoundly enriched, and IL6 and VEGF were involved. The molecular docking revealed the significant active compounds with hub genes and quercetin showed good binding to HIF-1α, which is involved in inflammation and angiogenesis. Experimental results verified that both herbs and QHG could regulate key ferroptosis-related targets in the retinal pigment epithelium and inhibit the expression of HIF-1α, VEGFA, and IL-6, subsequently increase cell viability and decrease the ROS content induced by H2O2.

CONCLUSION

This study demonstrates the molecular mechanism through which SM/FL and QHG protect against AMD and emerges as a plausible mechanism underlying this protection.

Qi-Shen-Tang alleviates retinitis pigmentosa by inhibiting ferroptotic features via the NRF2/GPX4 signaling pathway

Ferroptosis has been observed during retinal photoreceptor cell death, suggesting that it plays a role in retinitis pigmentosa (RP) pathogenesis. Qi-Shen-Tang (QST) is a combination of two traditional Chinese medicines used for the treatment of ophthalmic diseases; however, its mechanism of action in RP and ferroptosis remains unclear. Therefore, this study aimed to explore the effect and potential molecular mechanisms of QST on RP. QST significantly improved tissue morphology and function of the retina in the RP model mice. A significant increase in retinal blood flow and normalization of the fundus structure were observed in mice in the treatment group. After QST treatment, the level of iron and the production of malondialdehyde decreased significantly; the levels of superoxide dismutase and glutathione increased significantly; and the protein expression of glutathione peroxidase 4 (GPX4), glutathione synthetase, solute carrier family 7 member 11, and nuclear factor erythroid 2-related factor 2 (NRF2) increased significantly. The molecular docking results demonstrated potential interactions between the small molecules of QST and the key proteins of NRF2/GPX4 signaling pathway. Our results indicate that QST may inhibit ferroptosis by inhibiting the NRF2/GPX4 signaling pathway, thereby reducing RP-induced damage to retinal tissue.