Objective:To investigate the effects of down-regulation of Krüppel-like factor 5 (KLF5) on biological functions of rat intestinal epithelial cells IEC-6 in response to ionizing radiation.Methods:Rat intestinal epithelial IEC-6 cells were irradiated with 0, 2, 4, 8, 12, 16 Gy of X-rays and 3 h later the expression of KLF5 in IEC-6 cells was detected by Western blot. IEC-6 cells were irradiated to 12 Gy and 0, 0.5, 1, 2, 3, 5, 7 and 24 h later the expression of KLF5 in IEC-6 cells was detected by Western blot. shRNA sequences targeting rat KLF5 gene were designed, synthesized and inserted into the lentiviral vector. The recombinant lentiviral vectors were packaged in human embryonic kidney 293T cells, and the lentivirus titers were determined. IEC-6 cells were infected with the recombinant lentivirus, and the transfection efficiency was observed under fluorescence microscope. Real-time PCR and Western blot were used to detect the expressions of KLF5 mRNA and protein in the transfected cells 72 h post transfection. The consequent experiments included four groups: negative control group, shKLF5 group, radiation group and radiation + shKLF5 group. The cell viability was observed in KLF5 silencing cells irradiated with 8 Gy by using CCK-8 assay. The cell cycle distribution and apoptosis were detected in KLF5 silencing cells irradiated with 8 Gy by flow cytometry. Immunofluorescence staining was applied to visualize the γ-H2AX foci in nucleus of KLF5 silencing cells irradiated with 2 Gy.Results:The expression of KLF5 increased with the different doses. The expression of KLF5 increased first, then decreased and peaked at 5 h post-irradiation with 12 Gy. KLF5 shRNA lentiviral vectors were successfully constructed. The mRNA and protein level of KLF5 were down-regulated in recombinant lentivirus transfected IEC-6 cells 72 h after transfection. Knockdown of KLF5 markedly induced G 2/M phase arrest ( t=11.56, P<0.05), proliferation inhibition, more apoptosis rate [radiation group: (7.42±0.49)%, radiation + shKLF5 group: (12.49±0.63)%, t=10.98, P<0.05], and more γ-H2AX foci in nucleus post-irradiation than negative control ( t=22.07, 23.89, 11.24, 59.97, 20.85, P<0.05). Conclusions:The KLF5 knockdown intestinal epithelial cell line was successfully established. The down-regulation of KLF5 expression could induce cell arrest at G 2/M, suppress the proliferation of irradiated cells and improve the cell apoptosis, enhance DNA double strand breaks and prolong DNA damage repair.

Objective:To observe the clinical and imaging features of non-arteriotic central retinal artery occlusion (NA-CRAO) with internal boundary membrane detachment (ILMD), and to analyze its relationship with visual prognosis.Methods:A retrospective clinical study. A total of 88 patients with NA-CRAO hospitalized in Department of Ophtalmology, Xi'an People's Hospital (Xi'an Fourth Hospital) from January 2014 to June 2023 were included in the study. Best corrected visual acuity (BCVA), optical coherence tomography (OCT) and fluorescein fundus angiography (FFA) were performed. The BCVA test used the international standard visual acuity chart, which was statistically converted to the logarithm of the minimum angle of resolution (logMAR) visual acuity. OCT observed the presence of ILMD and the thickening of the inner retina and the disappearance of anatomical stratification. FFA recorded arm-retinal circulation time (A-Rct) and retinal arterion-distal filling time (FT), and observed ciliary retinal artery, fluorescein retrograde filling, cotton spots, luciferin nodal filling, macular non-perfusion, capillary fluorescein leakage, optic disc strong fluorescence, choroidal background weak fluorescence and other characteristics. According to whether there was ILMD, the patients were divided into ILMD group and non-ILMD group, with 44 cases and 44 eyes respectively. The two groups received the same treatment. The follow-up time was 30 days after treatment. The clinical, FFA characteristics and BCVA before and after treatment were compared between the two groups. t-test was used for comparison between groups. Results:In ILMD group and non-ILMD group, there were 43 cases of male and 1 case of female, respectively, and the proportion of male was significantly higher than that of female. Before and after treatment, the logMAR BCVA of ILMD group and non-ILMD group were 2.35±0.42, 2.01±0.46, 1.47±0.60, 0.77±0.49, respectively. There were significant differences in logMAR BCVA between the two groups before and after treatment ( t=8.025, 12.358; P<0.001). Before treatment, A-Rct and FT in ILMD group were longer than those in non-ILMD group, and the difference was statistically significant ( t=3.052, 3.385; P<0.05). After treatment, there was no significant difference ( t=1.040, 1.447; P >0.05). The proportion of ciliary retinal artery and cotton plaque in ILMD group was lower than that in non-ILMD group. There was no significant difference in ciliary retinal artery between the two groups ( χ2=-0.961, P>0.05), but there was a significant difference in cotton wool plaque between the two groups ( χ2=-3.364, P <0.05). Compared to the non-ILMD group, The proportion of retrograde fluorescein filling in retinal artery ( χ2=-2.846), segment filling ( χ2=-3.907), macular non-perfusion ( χ2=-6.656), capillary fluorescein leakage ( χ2=-4.367), optic disc strong fluorescence ( χ2=-3.525) and choroidal background weak fluorescence ( χ2=-2.276) increased, the difference was statistically significant ( P<0.05). Conclusions:In patients with NA-CRAO, compared with those without ILMD, those with ILMD have more severe retinal ischemia and worse BCVA before and after treatment. ILMD is one of the poor prognostic markers of NA-CRAO vision.

Rab27a gene can participate in the secretion, transportation and exocytosis of T lymphocytes, mast cells, neutrophils, pancreatic β cells and hematopoietic cells through its encoded proteins, and participate in the development of diseases such as albinism, cancer, diabetes, inflammation and thrombosis. In addition, the secretion regulation of Rab27a to exosomes has also received much attention. The current research status of the secretion of exosome and the genetically modified exosomes of Rab27a gene in the treatment of diseases such as inflammatory injury, thrombosis and tumor were reviewed.