Combined effects of micron-sized polyvinyl chloride particles and copper on seed germination of perilla

Microplastics (MPs) and copper (Cu) pollution coexist widely in cultivation environment. In this paper, polyvinyl chloride (PVC) were used to simulate the MPs exposure environment, and the combined effects of MPs + Cu on the germination of perilla seeds were analyzed. The results showed that low concentrations of Cu promoted seed germination, while medium to high concentrations exhibited inhibition and deteriorated the morphology of germinated seeds. The germination potential, germination index and vitality index of 8 mg • L-1 Cu treatment group with were 23.08%, 76.32% and 65.65%, respectively, of the control group. The addition of low concentration PVC increased the above indicators by 1.27, 1.15, and 1.35 times, respectively, while high concentration addition led to a decrease of 65.38%, 82.5%, and 66.44%, respectively. The addition of low concentration PVC reduced the amount of PVC attached to radicle. There was no significant change in germination rate. PVC treatment alone had no significant effect on germination. MPs + Cu inhibited seed germination, which was mainly reflected in the deterioration of seed morphology. Cu significantly enhanced antioxidant enzyme activity, increased reactive oxygen species (ROS) and MDA content. The addition of low concentration PVC enhanced SOD activity, reduced MDA and H2O2 content. The SOD activity of the Cu2+8 + PVC10 group was 4.05 and 1.35 times higher than that of the control group and Cu treatment group at their peak, respectively. At this time, the CAT activity of the Cu2+8 + PVC5000 group increased by 2.66 and 1.42 times, and the H2O2 content was 2.02 times higher than the control. Most of the above indicators reached their peak at 24 h. The activity of α-amylase was inhibited by different treatments, but β-amylase activity, starch and soluble sugar content did not change regularly. The research results can provide new ideas for evaluating the impact of MPs + Cu combined pollution on perilla and its potential ecological risk.

Oxidative stress and antioxidants in cataract development

PURPOSE OF REVIEW

Oxidative stress plays a central role in cataract pathogenesis, a leading cause of global blindness. This review delves into the role of oxidative stress in cataract development and key biomarkers - glutathione (GSH), superoxide dismutase (SOD), malondialdehyde (MDA), and 4-hydroxynonenal (4-HNE) - to clarify their functions and potential applications in predictive diagnostics and therapies.

RECENT FINDINGS

Antioxidants serve as pivotal markers in cataract pathogenesis. GSH affects the central lens due to factors such as enzyme depletion and altered connexin expression, impairing GSH diffusion. Age-related oxidative stress may hinder GSH transport via connexin channels or an internal microcirculation system. N-acetylcysteine, a GSH precursor, shows promise in mitigating lens opacity when applied topically. Additionally, SOD, particularly SOD1, correlates with increased cataract development and gel formulations have exhibited protective effects against posterior subscapular cataracts. Lastly, markers of lipid peroxidation, MDA and 4-HNE, have been shown to reflect disease severity. Studies suggest a potential link between 4-HNE and connexin channel modification, possibly contributing to reduced GSH levels.

SUMMARY

Oxidative stress is a significant contributor to cataract development, underscoring the importance of antioxidants in diagnosis and treatment. Notably, GSH depletion, SOD decline, and lipid peroxidation markers are pivotal factors in cataract pathogenesis, offering promising avenues for both diagnosis and therapeutic intervention.

Physiological analysis and transcriptome profiling reveals the impact of microplastic on melon (Cucumis melo L.) seed germination and seedling growth

The wide application of agricultural plastics leads to microplastic (MP) accumulation in the soil and inevitably result in MP pollution. Melon is an economically important horticultural crop that is widely cultivated with plastic film mulching. However, the impact of MP pollution on plant growth remains largely unclear. Here we reported the morphological, physiological, biochemical responses and transcriptome re-programing of melon responses to MP on seed germination and seedling growth. Polyvinyl chloride particles were added to potting mix to simulate MP exposure environment (MEE). The results showed that low and medium concentrations (1-4 g kg-1) of MEE had a significant adverse effect on seed germination and seedling growth. In both cases, the germination potential was decreased, young root forks increased, and tips decreased; and the dry weight of seedlings, the total length, surface area, forks and tips of root were also decreased. However, the root activity was increased. The concentration of MEE to give the best parameters was at 2 g kg-1. Catalase enzymatic activity and reactive oxygen species (ROS) in roots were decreased continuously with increased MEE concentrations. The peak values of peroxidase activity, O2.- content and generation rate, ROS enrichment and malondialdehyde content all reached the highest at 2 g kg-1. MEE also increased the proline content and decreased the contents of ascorbic acid, soluble sugar and soluble protein in these seedlings. Medium and high concentrations of MEE (4-8 g kg-1) also increased the chlorophyll b content. Low concentrations MEE (1-2 g kg-1) inhibited actual photochemical efficiency of photosystem II and photochemical quenching, two key chlorophyll fluorescence parameters. Transcriptome analysis showed that the differentially expressed genes caused by the MEE were mainly belonged to defense response, signal transduction, hormone metabolism, plant-pathogen interaction, and phenylpropanoid biosynthesis. The results of this study will help to understand the ecotoxicological effects of MEE on melons and provide data for ecological risk assessment of Cucurbitaceae vegetable cultivation.

Protection of Human Lens Epithelial Cells from Oxidative Stress Damage and Cell Apoptosis by KGF-2 through the Akt/Nrf2/HO-1 Pathway

Oxidative stress exerts a significant influence on the pathogenesis of various cataracts by inducing degradation and aggregation of lens proteins and apoptosis of lens epithelial cells. Keratinocyte growth factor−2 (KGF-2) exerts a favorable cytoprotective effect against oxidative stress in vivo and in vitro. In this work, we investigated the molecular mechanisms of KGF-2 against hydrogen peroxide- (H₂O₂-) induced oxidative stress and apoptosis in human lens epithelial cells (HLECs) and rat lenses. KGF-2 pretreatment could reduce H₂O₂-induced cytotoxicity as well as reactive oxygen species (ROS) accumulation. KGF-2 also increases B-cell lymphoma-2 (Bcl-2), quinine oxidoreductase-1 (NQO-1), superoxide dismutase (SOD2), and catalase (CAT) levels while decreasing the expression level of Bcl2-associated X (Bax) and cleaved caspase-3 in H₂O₂-stimulated HLECs. LY294002, the phosphatidylinositol-3-kinase (PI3K)/Akt inhibitor, abolished KGF-2's effect to some extent, demonstrating that KGF-2 protected HLECs via the PI3K/Akt pathway. On the other hand, KGF-2 activated the Nrf2/HO-1 pathway by regulating the PI3K/Akt pathway. Silencing nuclear factor erythroid 2-related factor 2 (Nrf2) by targeted-siRNA and inhibiting heme oxygenase-1 (HO-1) through zinc protoporphyrin IX (ZnPP) significantly decreased cytoprotection of KGF-2. Furthermore, as revealed by lens organ culture assays, KGF-2 treatment decreased H₂O₂-induced lens opacity in a concentration-dependent manner. As demonstrated by these data, KGF-2 resisted H₂O₂-mediated apoptosis and oxidative stress in HLECs through Nrf2/HO-1 and PI3K/Akt pathways, suggesting a potential protective effect against the formation of cataracts.

The Pathomechanism, Antioxidant Biomarkers, and Treatment of Oxidative Stress-Related Eye Diseases

Oxidative stress is an important pathomechanism found in numerous ocular degenerative diseases. To provide a better understanding of the mechanism and treatment of oxidant/antioxidant imbalance-induced ocular diseases, this article summarizes and provides updates on the relevant research. We review the oxidative damage (e.g., lipid peroxidation, DNA lesions, autophagy, and apoptosis) that occurs in different areas of the eye (e.g., cornea, anterior chamber, lens, retina, and optic nerve). We then introduce the antioxidant mechanisms present in the eye, as well as the ocular diseases that occur as a result of antioxidant imbalances (e.g., keratoconus, cataracts, age-related macular degeneration, and glaucoma), the relevant antioxidant biomarkers, and the potential of predictive diagnostics. Finally, we discuss natural antioxidant therapies for oxidative stress-related ocular diseases.

The association between food diversity and serum antioxidant indices in cataract patients compared to healthy subjects

BACKGROUND

Cataract is a chronic disorder that is related to antioxidant-oxidant imbalance situation. We aimed to investigate the association between food diversity and serum antioxidant and oxidant indices in cataract patients compared to healthy subjects.

MATERIALS AND METHODS

In this case-control study, ninety volunteers (aged > 50 years) were divided into the cataract (n = 45) and healthy control (n = 45) groups. Anthropometric variables, physical activity and stress levels, food diversity score, serum total oxidant capacity (TOC), and total antioxidant capacity (TAC) measurements were done for all participants.

RESULTS

Serum TAC, even after adjustment for stress level, was significantly higher in healthy people compared to cataract patients (P < 0.001). In addition, serum TOC was significantly lower in healthy controls compared to cataract patients (P < 0.002). In healthy group, there was a weak significant positive association between serum TAC and meats group diversity (r = 0.149, P = 0.047). In addition, there was a moderate negative association between meats group diversity and TOC in the healthy controls (r = -0.712, P = 0.041). In the cataract group, there was a significant negative association between serum TOC and diversity score of fruits (r = -0.811, P = 0.017) and meats group (r = -0.926, P = 0.046) as well as total score of food diversity (r = -0.466, P = 0.003).

CONCLUSION

It seems that increase in total dietary diversity and food groups' diversity can have a beneficial effect on oxidant situation among cataract patients.

Hallmarks of lens aging and cataractogenesis

Lens homeostasis and transparency are dependent on the function and intercellular communication of its epithelia. While the lens epithelium is uniquely equipped with functional repair systems to withstand reactive oxygen species (ROS)-mediated oxidative insult, ROS are not necessarily detrimental to lens cells. Lens aging, and the onset of pathogenesis leading to cataract share an underlying theme; a progressive breakdown of oxidative stress repair systems driving a pro-oxidant shift in the intracellular environment, with cumulative ROS-induced damage to lens cell biomolecules leading to cellular dysfunction and pathology. Here we provide an overview of our current understanding of the sources and essential functions of lens ROS, antioxidative defenses, and changes in the major regulatory systems that serve to maintain the finely tuned balance of oxidative signaling vs. oxidative stress in lens cells. Age-related breakdown of these redox homeostasis systems in the lens leads to the onset of cataractogenesis. We propose eight candidate hallmarks that represent common denominators of aging and cataractogenesis in the mammalian lens: oxidative stress, altered cell signaling, loss of proteostasis, mitochondrial dysfunction, dysregulated ion homeostasis, cell senescence, genomic instability and intrinsic apoptotic cell death.

Medicinal Plants and Natural Products Used in Cataract Management

Cataract is the leading reason of blindness worldwide and is defined by the presence of any lens opacities or loss of transparency. The most common symptoms of cataract are impaired vision, decreased contrast sensitivity, color disturbance, and glare. Oxidative stress is among the main mechanisms involved in the development of age-related cataract. Surgery through phacoemulsification and intraocular lens implantation is the most effective method for cataract treatment, however, there are chances of serious complications and irreversible loss of vision associated with the surgery. Natural compounds consisting of antioxidant or anti-inflammatory secondary metabolites can serve as potential leads for anticataract agents. In this review, we tried to document medicinal plants and plant-based natural products used for cataract treatment worldwide, which are gathered from available ethnopharmacological/ethnobotanical data. We have extensively explored a number of recognized databases like Scifinder, PubMed, Science Direct, Google Scholar, and Scopus by using keywords and phrases such as “cataract”, “blindness”, “traditional medicine”, “ethnopharmacology”, “ethnobotany”, “herbs”, “medicinal plants”, or other relevant terms, and summarized the plants/phytoconstituents that are evaluated in different models of cataract and also tabulated 44 plants that are traditionally used in cataract in various folklore medical practices. Moreover, we also categorized the plants according to scientific studies carried out in different cataract models with their mechanisms of action.

Ghrelin Protects Human Lens Epithelial Cells against Oxidative Stress-Induced Damage

Oxidative stress has been recognized as an important mediator in the pathogenesis of age-related cataracts; using antioxidant supplements is one plausible strategy to protect the antioxidative defense system against oxidative stress. Ghrelin administration is expected to reduce ROS, preventing the onset of different diseases. The role of ghrelin, if any, in protecting against oxidative stress in HLECs has never been examined. In the present study, we investigated the effects of ghrelin against H₂O₂-induced oxidative stress and the associated molecular mechanisms in HLECs and rat lenses. The results showed that pretreatment with ghrelin reduced H₂O₂-induced cellular apoptosis and ROS accumulation, increased the expression levels of SOD and CAT, and decreased the expression level of MDA. The morphological examination showed that the ghrelin-treated lens organ culture maintained transparency. This is the first report to show that ghrelin can protect HLECs from H₂O₂-induced oxidative stress. Our findings suggest that ghrelin may prevent the progression of cataracts, which has treatment value for ophthalmologists.