A Study On The Retina Injury And The Mechanism By Organophosphate Poisoning

Background The injury of nerve cell by orgnaophosphorus compound is the main point of this filed. Retina is the extensive part of the central nervous system. There are often some cases of retina injure disease by organophosphate poisoning during clinical work, but the study on the mechanism of retina injury after organophosphate poisoning is rare. Our study wants to establish the animal poisoning models and detect the effects of orgnaophosphorus compound on the retina nerve cell. From the point of view of overload acetylcholine induce the exitotoxicity of aminoglutaminic acid, then induce the calcium overload in the retina nerve cell and lead to the injury of nerve cell and to discuss the mechanism of retina injury after organophosphate poisoning.Objective Applying the theories of pathophysiology, setting out from the facts of clinical work, through establishing the animal poisoning models to investigate the injury of orgnaophosphorus compound on the retina nerve cell. And binding with some correlated theories, from the point of view of overload acetylcholine induce the exitotoxicity of aminoglutaminic acid, then induce the calcium overload in the retina nerve cell and lead to the injury of nerve cell and to discuss the mechanism of retina injury after organophosphate poisoning. In order to provide the scientific evidences of the health of the people who produce or use orgnaophosphorus compound and to protect the environment and more effectively use it and to prevent beforehand the impaired vision of the clinical patients.Methods The study was divided into two parts.Part I : Study on the observation of the retina injury after organophosphate poisoning.1,Establish the mouse orgnaophosphorus insecticides poisoning modelsby durshan. 40 mouse were divided into five groups: control group, poisoning group (2h,12h,24h,36h) . Detach the retina after 2h,12h,24h and 36h. Allthe mouse was observed in condition of HE stain and tigroid body staining under light microscope and transmission electron microscope.2,Establish the rabbit orgnaophosphorus insecticides poisoning modelsby DDVF, Metrifonate and Dimethoate.20 healthy rabbits were divided into four groups: control group, poisoning group (DDVF, Metrifonate and Dimethoate). Establish the primary cell cultivating system of the retina nerve cell. Trypanblau staining was used for examining the survival state by organophosphate poisoning. MTT colorimetry was used for examining the effects of orgnaophosphorus on the activity of retina cell. Lactate dehydrogenase assay was used for examining the change of leakage quantity of LDH on the orgnaophosphorus poisoning cells.Part II : Study on the mechanism of the retina injury afterorganophosphate poisoning.1. Establish the mouse orgnaophosphorus insecticides poisoning models by durshan. Detach the retinas and all the retinas were observed in condition of fluo- 3/AM fluorescence technique stain. Observe the changes of intracelluLar calcium of mouse retinal neuron cells under laser scanning confocal microscope.2. Establish the rabbit orgnaophosphorus insecticides poisoning models by DDVF, Metrifonate and Dimethoate. RT-PCR was performed for analysis of the expression of NR1 subunit gene in the orgnaophosphorus insecticides poisoning rabbit retina tissues and normal rabbit retina tissues.ResuLts Part I : Study on the observation of the retina injury after organophosphate poisoning. 1. HE light microscope showed that there is no obvious change between the control group and the poisoning groups. Tigroid body staining showed that the reduced quantity of tigroid body in the poisoning groups and some of the nerve cell cytoplasm showed vacuolar degeneration. electron microscopic section showed that the vacuolar degeneration in visual cell of the poisoning group and the outer segment of visual cell membrane breakage and derangement in alinement, appearing many irreguLar fragment of the outer segment of visual cell membrane. The inner segment of visual cell became edema to appearing irreguLar shapes and more vacuolus. The neurite of visual cell showed edema, understain and microtubuLe moving to edge. The endoplasmic reticuLum edema, MuLler cells appears to vacuolar degeneration. And with the time go, the photography of transmission electron microscope showed the damage of retinal cells became more severe.2. Trypanblau staining showed that the death rate of the organophosphate poisoning group have heightened which have statistics disparity comparing to control group (p<0.01). MTT colorimetry showed that the cell activity of the organophosphate poisoning group have descent to some different extent which have statistics disparity comparing to control group (p<0.05). Lactate dehydrogenase assay showed that leakage quantity of LDH of the organophosphate poisoning group have heightened which have statistics disparity comparing to control group (p<0.01).Part II: Study on the mechanism of the retina injury afterorganophosphate poisoning.3. Fluo- 3/AM fluorescence technique stain showed that : the fluorescence intensity of the control group retina tissue only showed 46.03, the fluorescence intensity of the 36h poisoning group retina tissueshowed98.97 which have statistics disparity comparing to control group (p<0.01).The resuLt by laser scanning confocal microscope demonstrated that fluorescence intensity in poisoning mouse retinal neuron cells was obviously enhanced.4. NR1 mRNA was not detected in 0% (0/10) of the control group normal retina tissues, but it was detected in 76.67% (23/30) of poisoning grouptissues. In addition, the expression of NR1 mRNA has notable significant correlation with the time that orgnaophosphorus poisoning has taken place. (12h, 24h poisoning retina tissue showed no expression of NR1 mRNA,48h poisoning retina tissue showed the expression of NR1 mRNA ).Conclusion 1 .Orgnaophosphorus compound can lead to the morphological injury of the retina tissues after organophosphate Poisoning have taken place. The main injury was in the cone cell and the rod cell. And with the time go, the photography of transmission electron microscope showed the damage of retinal cells became more severe.2. Orgnaophosphorus compound can influence the retina nerve cell's activity and the survival state.3. The mechanism of the retina injury after organophosphate poisoning may related to it has induce overload acetylcholine which induce the exitotoxicity of aminoglutaminic acid through NMDAR, then induce the calcium overload in the retina nerve cell and lead to the injury of nerve cell.