| AIMS1. To establish a stable and reproducible chronic ocular hypertension (OHT) model by intracameral injection 3g/L carbomer in rabbits eyes.2. Using the successful OHT model, to investigate the protective effect of extract of crocus sativus on retina in rabbit with chronic OHT.METHODS1. Left eyes of ten rabbits were treated as control eyes, right eyes were treated as model eyes. The OHT model was induced by intracameral injection 3g/L carbomer in model eyes, whereas the control eyes were only performed paracentesis without injection of carbomer. IOP was measured once every day after injection.Amplitudes of b-wave and Ops-wave were measured before and after injection 1, 2, 4 weeks, respectively. On 4 weeks, the number of RGCs was counted.2. When the successful OHT model was established, thirty rabbits were randomly divided into control group, OHT group and treated groups. The IOP was elevated by 3g/L carbomer injection into the anterior chamber of rabbits in OHT group and three treated groups. The control group was performed paracentesis without injection of carbomer. Extract of crocus sativus was injected into veins of rabbits in treated groups once every day and for 4 weeks totally. Doses of injection were 20mg/Kg, 40 mg/Kg and 80 mg/Kg, respectively.3. Amplitudes of b-wave and Ops-wave of ERG were measured before and after injection 1, 2, 4 weeks. On 4 weeks, enucleation of eyeballs of rabbits was performed. Specimen of retina was made. Thicknesses of neurosensory retina, inner retinal layer (IRL), outer retinal layer (ORL) and retinal nerve fiber layer (RNFL) were measured. The number of RGCs was counted. The ultrastructure of RGCs was studied with electron microscopes.RESULTS1. In the first experiment, (1) The IOP of model eyes was (33.53±10.58) mmHg, and significantly higher than that of control eyes (15.67±1.88) mmHg (7=4.798, P=0.001). (2) Before and after injection 1, 2, 4 weeks, amplitudes of b-wave and Ops-wave in control eyes had significantly difference compared with those of model eyes. Amplitudes of b-wave and Ops-wave of model eyes also had significantly difference at different time and the trend todecrease throughtout the duration of OHT (P<0.01). (3) On four weeks, RGCs of control eyes were ( 302.30±23.99 ) /10mm. There was significantly difference in control eyes compared with those of model eyes (89.20±10.86) /10mm (t=23.685, P=0.001).2. In the second experiment, amplitudes of b-wave and Ops-wave of rabbits in OHT group were significantly lower than those of control group and three treated groups after injection 1, 2, 4 weeks, respectively. There was no remarkable change in thickness of neurosensory retina, IRL, ORL and RNFL in control group, treated group II and HI. However the slight atrophy and thinner of neurosensory retina was obseverd in treated group I . The significant changes were also observed in neurosensory retina in OHT group, including derangement of cells in inner nuclear layer and outer nuclear layer, atrophy and thinner of neurosensory retina. Thicknesses of neurosensory retina, IRL, ORL and RNFL in OHT group had significantly difference with those in control group and three treated groups. Number of RGCs: control group was( 311.75±22.56 )/10mm; the OHT group was ( 62.83±11.13 VlOmm; treated group I was ( 100.00±23.98 ) /10mm; treated group II was( 288.16±36.47 ) /10mm and treated group HI was ( 299.75±20.33 ) /10mm. The OHT group had significantly difference with other four groups. The treated group I had significantly difference with control group, treated group II and III. There were no significantly differences among control group, treated group II and III. The ultrastructure of RGCs in OHT group had remarkable changes, including loss of nucleolus, concentration of chromatin, swelling of mitochondrion. Whereas slight change of RGCs in treated group I was observed, including slight swelling of mitochondrion,... |
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