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Objective:To investigate the rat retinal DNA damage induced by acute hypobaric hypoxia and the protective effect of Radix Astragali seu Hedysari compound on it. Methods:Seventy-two healthy clean grade male Sprague Dawley (SD) rats were randomly divided into normal oxygen control group, hypoxic model group and Radix Astragali seu Hedysari compound gavage group by computer random number distribution, with 24 rats in each group.The rats in the normal oxygen control group were fed in normal condition, while the rats in the hypoxic model group and Radix Astragali seu Hedysari compound gavage group were fed in a hypobaric oxygen chamber, which simulated an altitude of 5 kilometers, and the rats were administered intragastrically with Radix Astragali seu Hedysari compound (0.1 g/kg) or the same volume of normal saline once a day according to grouping.Retinal tissue was obtained on the 7th day of continuous administration of drugs after the rats were sacrificed by euthanasia.Histopathological staining was performed to observe the pathological morphology of retina in each group.Immunohistochemistry was used to identify the expressions of p53 and histone family 2A variant ( γH2AX). Real time-PCR was used to determine the relative expression levels of 8-oxoguanine nucleoside triphosphatase (MTH1) and 8-hydroxyguanine glycolsylase (OGG1) mRNA.The use and care of the animals followed Regulations of the Administration of Affair Concerning Experimental Animals by State Science and Technology Commission. Results:The retina of hypoxic model group was thicker than that of the normal oxygen control group and Radix Astragali seu Hedysari compound gavage group, especially the nerve fiber layer and the ganglion cell layer.The positive staining intensities of p53 and γH2AX were stronger in the retinas of the hypoxic model group than those in the the normal oxygen control group and Radix Astragali seu Hedysari compound gavage group.The relative expression levels of MTH1 and OGG1 mRNA in the hypoxic model group were 0.573±0.081 and 0.772±0.136, which were significantly lower than 0.846±0.160 and 1.013±0.168 in the normal oxygen control group, respectively (both at P<0.05). The relative expression level of MTH1 mRNA was 0.748±0.114 in the Radix Astragali seu Hedysari compound gavage group, significantly higher than that in the hypoxic model group ( P<0.05). No significant difference was detected in OGG1 mRNA expression level between the Radix Astragali seu Hedysari compound gavage group and the hypoxic model group ( P=0.743). Conclusions:The intervention of Radix Astragali seu Hedysari compound plays a protective role in hypobaric hypoxia-induced retinal DNA damage through modulating the expression of p53, γH2AX, OGG1 and MTH1.
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Background Meningothelial cells (MECs) occupy the predominant cell component of barrier between optic nerve and the cerebral spinal fluid,and any change of cerebral fluid components probably affects the MECs function and further impairs the optic nerve.Objective This study was designed to investigate the influence of glutamate,a potentially excitotoxic amino acid,to the functional changes of MECs and provide a theoretical evidence for clarifying the mechanism of optic nerve disorders.Methods Human MECs strains were cultured in vitro and prepared into cell suspension.The cells were inoculated to 96-well plates with the densities of 1 × 104/we11.The glutamate of 100,200,400,600,800 and 1 000 μmol/L was added into medium for 12,24,36,48 and 72 hours,respectively,and the cultured cells without glutamate were used as normal control group.MTS assay was employed to measure the proliferative rate (absorbency) of the cells.The regularly cultured MECs were divided into 600 μmol/L glutamate-treated group and normal control group and the cells were treated for 12 and 24 hours respectively,and the expression of superoxide dismutase (SOD) mRNA and heat shock protein 90 (HSP90) mRNA in the cells was detected by real-time PCR;the level of total anti-oxidative capacity (T-AOC) of the cells was processed by enzyme linked immunosorbent assay (ELISA),and the reactive oxygen species (ROS) production was determined by DCFH-DA probe.Results Cultured MECs grew well and formed 80％ confluence after 72 hours culture.The proliferative rate of the cells were gradually decreased with the increase of glutamate dose and the lapse of affected time,with significant differences among different concentrations of glutamate and various time points (F tration =52.501,P＜0.001;Ftime =8.505,P＜0.001).The relative expression level of SOD mRNA was significantly reduced in the glutamate-treated group compared with the normal control group in both 24 hours and 48 hours after culture (t =20.278,t =16.724,both at P＜0.001),and the expression of HSP90 mRNA in the cells was significantly lower in the glutamate-treated group than that in the normal control group in 24 hours after culture (t =5.065,P =0.002).No significant difference was found in T-AOC activity between glutamate-treated group and normal control group in 24 hours after culture ([30.835±2.094] nmol/(min · L) vs.[32.873±2.317] nmol/(min · L)) (t=1.599,P =1.414).In 48 hours after culture,T-AOC activity was (29.561 ± 1.831) nmol/(min · L) in the glutamate-treated group,which was significantly lower in comparison with normal control group (33.680±2.039) nmol/(min · L)(t =3.682,P =0.004).Fluorescence staining showed that the intensity of green fluorescence of ROS in MECs in the normal control group was weaker than that in the glutamate-treated group under the immunofluorescense microscope.The ROS level was 48.110± 1.712 and 40.982± 1.853 at 24 hours and 48 hours in the glutamate-treated cells,and which was significantly elevated in comparison with 36.608± 1.009 and 37.153 ± 1.424 in the normal control group (t=14.178,P＜0.001;t=4.012,P=0.002).Conclusions Glutamate inhibits the proliferation of MECs in vitro,and excitatory toxicity of glutamate on MECs probably is associated with oxidative stress response.
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Background:Colorectal polyps,especially adenomatous polyps are the precusor of colorectal cancer. Screening and polypectomy by using colonoscopy is an important approach for prevention of colorectal cancer. Aims:To conduct a retrospective analysis among 1 613 cases of patients with colorectal polyps in Jiading District,Shanghai,China for guiding the management of colonoscopy surveillance of colorectal polyps. Methods:A total of 2 652 colorectal polyps detected by colonoscopy from Jan. 2013 to Aug. 2014 in the Endoscopy Center of Shanghai Ruijin Hospital Northern Branch were recruited in the study. Clinicopathological features of the polyps,coincidence rate of biopsy pathology and polypectomy pathology,and the re-detected polyps in colonoscopic follow-up were analyzed. Results:In 2 652 colorectal polyps,1 996 (75. 3% )were located in distal colon;adenomatous polyps accounted for 77. 5%(2 056 / 2 652)of the polyps detected by colonoscopy,of which 804(39. 1% )were found to have intraepithelial neoplasia. Both biopsy pathology and polypectomy pathology were obtained in 447 polyps,with an overall coincidence rate of 60. 4% ;as for adenomas,the coincidence rate was 68. 1% . Two hundred and eighteen pathologically proved polyps were found in a 1. 5-year colonoscopic follow-up, among which 74. 3% were adenomatous polyps;the re-detection rate of polyps located in proximal colon or less than 1. 0 cm in diameter was significantly higher than polyps located in distal colon and more than 1. 0 cm in diameter, respectively(12. 3% vs. 6. 9% and 9. 0% vs. 4. 5% ,P all < 0. 01). Conclusions:Adenomatous polyps account for high proportion of colorectal polyps detected by colonoscopy. Pathological examination of resection specimens and periodical follow-up are important for patients with colorectal polyps after endoscopic polypectomy.
ABSTRACT
Background BackgroundMeningothelial cells (MECs) are major cell type in the meningeal sheath around optic nerve,which form a fluid barrier between optic nerve and the cerebral spinal fluid.The impairment of the cerebral fluid-optic nerve barrier probably affects the balance of cerebral fluid components.Currently,the investigation on the role of MECs in neuropathy is less performed.Objective This study attempted to explore hypoxia-induced function changes of MECs,and to shed a new clus for the future research of optic nerve disorders.Methods Human MECs strains were cultured in vitro and cell suspension was prepared with the cell densities of 2.5 ×103/hole,5.0× 103/hole and 1 x 104 /hole,respectively.The suspensions of 100 μl were separately collected to incubate in 96-well plates and cultivated for 2 days in 21％ O2(normoxia group) or 1％ O2(hypoxia group).MTS was used to detect and compare the proliferative value (A490) of MECs between the normoxia group and the hypoxia group.The changes of MECs diameter and volume were measured by CASY1 assay.ATP product in the cells after MECs exposed to different oxygen environments with or without substrate (100 mmol/L pyruvate and 100 mmol/L malate) for 1,2 days were assayed by Luminometer method.The expression and distribution of cytochrome C in the cells of the normoxia group and the hypoxia group were determined by immunofluorescence.Results A490 of MECs in the 2.5× 103/hole,5.0× 103/hole and 1 × 104/hole were 0.399±0.009,0.393±0.009 and 0.496±0.026 in the hypoxia group,which were lower than 0.424±0.131,0.413±0.111 and 0.537±0.021 in the normoxia group (t =3.777,P =0.004 ; t =3.251,P =0.009 ; t =3.037,P =0.013).Compared with the normoxia group,the diameter and volume were significantly increased in the hypoxia group ([20.970 ±0.127] μm vs.[21.198 ±0.048] μm,t =-3.762,P=0.006; [5805±73] fl vs.[6026±106] fl,t=-4.124,P=0.002).ATP products were (0.900±0.225)mmol/(L· g) and (0.952± 0.075) mmol/(L · g) in the hypoxia group and the hypoxia+substrate group,which were significantly lower than (1.389±0.145) mmol/(L · g) and (1.401±0.122) mmol/(L · g) in the normoxia group and the normoxia +substrate group (P =0.001,0.002,0.001).Immunofluorescense staining showed that the green fluorescence of cytochrome C located at mitochondria of MECs in the normoxia group,but in the hypoxia group,cytochrome C distributed in the cytoplasm extensively.Conclusions Hypoxia induces malfunction of MECs,which might impact the intact of the cerebral spinal fluid-optic nerve barrier and therefore influence the microenvironment of the subarachnoid space and neuronal function.