Effect of nano-selenium loaded with lycium barbarum polysaccharide on the proliferation of lens epithelial cells after UVB damage in vitro

AIM: To investigate the effect of nano-selenium loaded with different concentrations of lycium barbarum polysaccharide (LBP-SeNPs) on the proliferation of human lens epithelial cells (HLECs) from UV irradiation. METHODS: LBP-SeNPs were prepared and their particle size was detected. HLECs (SRA01/04) were irradiated with UVB for different time (0, 10, 20, 30, 40, 50, 60min) to construct a damaged model, the survival rate of cells was determined by methylthiazol tetrazolium (MTT) assay. The 4',6-Diamidine-2'-phenylindole dihydrochloride (DAPI) staining was used to observe the status of cell nucleus and drug entering cytoplasm through cell membrane in SRA01/04 cells after adding LBP-SENPS loaded with coumarin fluorescence agent 24h under fluorescence microscope. SRA01/04 normal and UVB-damaged cells were treated with different amounts of LBP-SeNPs at different concentrations, cells proliferation were observed. RESULTS: The particle size of LBP-SeNPs was stable in the range of 150-200 nm. The survival rate changes with time after UVB irradiation were statistically significant. The 10min of UVB exposure as the time was chosen to construct the cell damage model. With DAPI staining, LBP-SeNPs were observed to enter the cytoplasm through the cell membrane under fluorescence inverted microscope. Cytotoxicity of SRA01/04 at different concentrations of LBP-SeNPs were measured. Cell survival rate was statistically different compared with the control group. The higher the loading concentration of LBP in nano-Se drugs was, the higher the cell proliferation rate was (P<0.05). The lower the concentration of LBP-SeNPs, the higher the cell proliferation rate, showing a negative growth trend (P<0.05). The group with the highest average cell proliferation rate was 0.5 µmol/L 2.0 mg/mL LBP-SeNPs (128.80%). When the 2.0 mg/mL LBP-SeNPs group was selected for cell photography, the cell density was higher at 0.5 μmol/L. With the increase of concentration, SRA01/04 cells appeared more cytoplasm dehydration, cell shrinkage and apoptotic bodies, and cell density decreased. CONCLUSION: LBP-SeNPs has moderate particle size and good stability. LBP-SeNPs can protect HLECs (SRA01/04) from UVB-induced damage, and the cell proliferation rate is further increased with increasing the amount of loaded LBP and decreasing nano-selenium concentration.

Radiation-Induced Alterations in Proliferation, Migration, and Adhesion in Lens Epithelial Cells and Implications for Cataract Development

The lens of the eye is one of the most radiosensitive tissues. Although the exact mechanism of radiation-induced cataract development remains unknown, altered proliferation, migration, and adhesion have been proposed as factors. Lens epithelial cells were exposed to X-rays (0.1–2 Gy) and radiation effects were examined after 12 h and 7 day. Proliferation was quantified using an MTT assay, migration was measured using a Boyden chamber and wound-healing assay, and adhesion was assessed on three extracellular matrices. Transcriptional changes were also examined using RT-qPCR for a panel of genes related to these processes. In general, a nonlinear radiation response was observed, with the greatest effects occurring at a dose of 0.25 Gy. At this dose, a reduction in proliferation occurred 12 h post irradiation (82.06 ± 2.66%), followed by an increase at 7 day (116.16 ± 3.64%). Cell migration was increased at 0.25 Gy, with rates 121.66 ± 6.49% and 232.78 ± 22.22% greater than controls at 12 h and 7 day respectively. Cell adhesion was consistently reduced above doses of 0.25 Gy. Transcriptional alterations were identified at these same doses in multiple genes related to proliferation, migration, and adhesion. Overall, this research began to elucidate the functional changes that occur in lens cells following radiation exposure, thereby providing a better mechanistic understanding of radiation-induced cataract development.

Metformin protects lens epithelial cells against senescence in a naturally aged mouse model

The senescence of lens epithelial cells (LECs) is a major factor leading to age-related cataract (ARC). ARC results in visual impairment and severe vision loss in elderly patients. However, the specific mechanism of ARC remains unclear, and there are no effective therapeutic agents to halt the formation of ARC. This study aimed to assess the underlying mechanism of the formation of ARC and investigate the potential anti-ageing effect of metformin (MET) on ARC. Male C57BL/6 mice were divided into three groups: the control group having young mice (3 months old, n = 40), the naturally aged group (aged 20 months, n = 60) and the MET group (MET, 20 months, n = 60). Mice in the control and the naturally aged groups were fed a standard purified mouse diet ad libitum and water, whereas those in the MET group were fed chows supplemented with 0.1% MET for 10 months. The transparency of the lens and age-associated proteins p21 and p53 were analysed in the LECs of these three groups. Furthermore, we determined the expressions of the adenosine monophosphate (AMP)-activated protein kinase (AMPK) pathway and the effect of MET on this pathway in LECs during the ageing process of ARC. In addition, the relationship between autophagy and the senescence of LECs and the role of MET in the autophagy of LECs during the ageing process of ARC were examined. Our results indicated that age-related inactivation of the AMPK pathway and impairment of autophagy might contribute to the senescence of LECs and the occurrence of ARC. More importantly, these results demonstrated that MET effectively alleviated the senescence of LECs and the formation of ARC probably via inactivation of the AMPK pathway and augmentation of autophagy. These findings revealed that MET can be exploited as a potentially useful drug for ARC prevention. Our study will help in enlightening the development of innovative strategies for the clinical treatment of ARC.

Structural Characteristics of the Lens in Presenile Cataract

The purpose of this work is to examine the structure of the anterior lens epithelial cells (aLECs) of presenile idiopathic cortical cataract to investigate the possible structural reasons for its development. The anterior lens capsules (aLCs: basement membrane and associated lens epithelial cells) were obtained from routine uneventful cataract surgery of 5 presenile cataract patients (16 and 41 years old women and 29, 39, and 45 years old men). None of the patients had family history of cataract, medication, or trauma and they were otherwise healthy. In addition, the patients did not have any other abnormal features in the ocular status except cataract. The aLCs were prepared for scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The most prominent abnormal features observed by SEM for all 5 studied presenile cataract patients were the changes of the aLECs structure with the dents, the selective concavity of some LECs, at their apical side centrally toward the nucleus. In addition, TEM showed the thinning of the lens epithelium with the segmentally concave cells and the compressed and elongated nuclei. Abnormal and distinguishable structural features were observed in the anterior lens epithelium aLECs in all 5 patients with presenile cataract. Disturbed structure of aLECs, regularly present in presenile cataract type is shown that might be associated with water accumulation in the presenile idiopathic cortical cataract lens.