Morphological Study On Retinal Ganglion Cells And Microvessels After Retinal Detachment Of Rabbits

Purpose. To investigate the morphological changes of the ganglion cells and microvessels of retina in order to probe into the mechanisms of visual function damage after retinal detachment(RD).Methods. RD models of 48 pigment rabbits were established by injecting hyaluronidase(10u/l) into the vitreous cavity, aspirating liquified vitreous and striking retina with stream of liquefied vitreous. Routine light microscopy and transmission electronmicroscopy were used to observe the retinal changes of the models at 6h,1d,3d,7d,14d and 28d after RD and to compare with the normal control group. In addition, stereology was used to measure the morphological changes in ganglion cells of the retina.Results. 1. Under the light microscope, the 6h model showed slight swelling of the cell body, lightly stained plasma, Nissl body missing in the central part but remaining in the periphery of the cell body in ganglion cells; in the 1d model, the ganglion cells were swollen, with the average sectional area through nucleus 51.4661±2.3050μm2(P<0.05); in the 3d model, the pericellular space enlarged, and the cell body diminished, the nucleus shifted eccentrically; in the 7d model, some ganglion cells shrinked and disappeared, with the number of cells 230.8333±4.8751(P<0.05), and nuclei were pyknotic, with average sectional area 48.4917±3.6944μm2 (P<0.05)；in 28d model, the quantity of ganglion cells decreased notably. 2. Ultrastructurally, in the 6h model, mitochondria were swollen with the average volume 0.8336±0.1739μm3 (P<0.05) and their cristae shortened with the surface density 2.9387±0.2098μm-1(P<0.05) in ganglion cells; in the 7d model, mitochondria were broken and reduced in number, with the average volume 0.3389±0.0678μm3; In 28d model, there was pycnosis and few mitochondria could be found in ganglion cells. 3. Obvious changes of microvessels could not be found under light microscope, but electronmicroscopically microvascular damages were marked. It was shown especially in irregular shape, swelling and thickening of the basement membrane; in addition, vacuoles, swollen mitochondria with shortened cristae were found in endothelial cells and pericytes.Conclusions. The severity of hypoxic damages of ganglion cell progresses with prolongation of RD, and pathological changes of retinal microvessels aggravate gradually, especially thickening of the basement membrane. The ischemic and hypoxic damages of ganglion cells resulted from microcirculatory disorder may contribute to visual impairment after RD.