| PURPOSEHemorrhagic retinal detachment (HRD) caused by many kinds of ocular trauma may lead to severe visual loss. With the unclear mechanism of retina damage, the clinical treatment is not effective. In order to set the initial foundation for the progressed study and treatment, we establish a HRD model in rabbits for the experimental study. The condition of detached retina and the elimination of subretinal hemorrhage are observed by direct ophthalmoscope, ultrasound B-scan and optical coherence tomography (OCT), the micro- and ultra-structural lesion are detected by histopathologic examination, and the visual function damage is evaluated through visual electrophysiology.METHODS1. Establishment of an animal model: Anticoagulation autologous blood of 0.2 mL was transvitreally injected into the subretinal space to produce HRD model in healthy pigmented rabbits, which were set as HRD group, while saline with or without heparin sodium of 0.2 mL was injected in control groups. The pseudo injection (puncture only without injection) and normal control groups were also set.2. Clinical observation of HRD model: Direct ophthalmoscope, OCT and ultrasound B-scan were performed 1 hour, 1, 3, 7, 14 and 28 days after HRD was set.3. Histopathologic examination of HRD model: light and electron microscope examinations were taken respectively 1 hour, 1, 3, 7, 14 and28 days after operation.4. Evaluation of visual function in HRD model: Electroretinogram (ERG) and visual evoked potential (VEP) were taken 2 days before, and 3 hours, 1, 3, 7, 14, 21, 28 days after establishment of HRD.RESULTS1 . HRD occurred in all eyes of the HRD group after operation. The HRD area extended from 10 to 12 disc diameters (DD). The obvious elevation maintained to 14 days, and the residual subretinal hemorrhage was still observed till 28 days. The obvious retinal detachment (RD) produced by the subretinal injected saline with or without heparin sodium in control groups was only kept for no more than 12 hours. The retinal puncture hole in pseudo injection group disappeared after 2 days, and there was no change in retina of normal control group.2. B-scan: In HRD group, the obvious highly dense reverberating echo band along with tightly clustered echo spots behind it connected to the posterior wall. The elevation almost descended to flat till 14 days, while the band of RD in control groups nearly disappeared after 1 day, and the reverberation in pseudo injection and normal groups was unchanged.3. OCT: The elevated neurosensory retina of HRD got thicker in early days and became thinner gradually, even vanished. There was residual subretinal hemorrhage till 28 days. Almost all the neurosensory retina of RD in control groups reattached in 3 days, and the reflectivity of choroid increased. There was no change in pseudo injection and normal groups.4. Light microscope: In HRD group, the subretinal space contained lots of erythrocytes, some leukocytes and fibrin. Most of photoreceptors broke in early stage, then cell numbers of outer and inner nuclear decreased. Retina disappeared in some parts of pre-injected area after 14 days, and there was blood residual in subretinal space till 28 days. In control group with saline with or without heparin sodium, the retina displayed likeserous RD, most of all retina reattached after 7 days, photoreceptors became short and disordered, part of the outer and inner nuclear layers got thinner, and pigment of RPE turned turbulence. Some cells showed edema in pseudo injection group 1 hour after operation.5. Electron microscope: In HRD group, part of outer segments of photoreceptor broke into pieces, mitochondria of inner segments swelled in early stage, then outer segments were broken, separated and absent, inner segments became degeneration and fragmentary, outer and inner nuclear layers showed karyopyknosis and karyorrhexis, and the cell number decreased. All layers of retina or both photoreceptors and outer nuclear layer in...
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