The Impact Of Progesterone To The Repair Of Rat Optic Nerve Injury

Objective: Optic nerve injury is a common clinical ocular trauma andserious person often leads to permanent loss of visual acuity. It is one of theblind eye diseases. At present, in clinical mainly use the drug to treat thisdisease which is always ineffective and having more side effects. Therefore,the ophthalmic scholars are concerned to find an effective drug treatment. Inrecent years, domestic and foreign scholars in brain injury research found thatprogesterone replacement therapy can delay the neuronal apoptosis, reduceedema, promote the synthesis of myelin in various animal models and play animportant role in nervous system damage and degenerative disease.Progesterone is a nervous system synthetic neuroactive steroid and theprotective effects of it in the nervous system get more and more clinicalattention. The effects of progesterone on optic nerve damage have beenreported rarely. To observe the modality of retinal ganglion cells byestablishing the injury model of rats' optic nerves and treatment ofprogesterone. To investigate the protective mechanism of progesterone toretinal ganglion cells and provide experiment basement for the therapy ofoptic nerve injury according to the semi-quantitative determination of theexpression of IGF-1and AQP4by immunohistochemistry method and theanalytic technique of computer image.Methods: Fifty female SD rats were healthy and clean breezed, theweight was200g±20g.All of them had no disease of eyes according toexamination. They were randomly divided into three groups, normal groupwith10rats (20eyes, the normal group had no treatment), control group with20rats and treatment group with20rats. In the control group and treatmentgroup, the right eye of every rat was made to the incomplete injury model ofoptic nerve and the optic nerve at temple side of rat eyeball was exposed. Optic nerves at2mm behind the eyeball were crushed with40g forceps atreverse direction in20s. After1days,3days,7days,14days and28days ofinjury, four eyes of every group were collected for experiment.For the controlgroup, distilled water was injected to the rats' abdominal cavity (8mg/kg) afterone hour of injury,for once a day and until the end of experiment. For thetreatment group, progesterone was injected to the abdominal with the samedose and frequency as that of control group. Four optic retinas of every groupwere taken. Fixed, embedded, sliced for HE staining to observe themorphological changes of the retina and detect the mean OD value of IGF-1and AQP4through immunohistochemical method at5time point after injury.SPSS13.0software package was used in this study, variance analysis andtwo-sample t test were expressed by±s.Results:1The results of HE stain1.1Normal group the integrity of the retina was smooth, retinal ganglion cellswere ovoid, cell size was consistent, nuclear was clear, outline was regular, theboundary of the cells was clear, and thickness and dyeing of inner and outerplexiform layers were uniform.1.2The control group One day after injury, the retinas started to edema, retinalganglion cells layer, inner and outer nuclear layer cells were arranged a littledisorder, cellular gap increased than the normal group. Three days after injury,the edema of retinal became serious, the number of retinal ganglion cellsreduced and majority of them could see vacuolated changes, nucleus presentthe state of pycnosis, the distribution of chromatin was unevenness,thearrange of inner and outer nuclear layer cells was loose and disorder. Sevendays after injury, the edema of retinal started to alleviate, a large number ofretinal ganglion cells could see the change of vacuolation, the number of cellsreduced significantly, the arrange of inner and outer nuclear layer cells weremore loose and disorder. Fourteen days after injury, the edema of retinal wasslightly disappeared; the shape and number of cells were close to the time of7day. 1.3The treatment group one day after injury, the retina was edema slightly,retinal ganglion cells layer had not obvious change, the arrangement of outernuclear layer cells were disorder injury, slightly the interspace of inner nuclearcells layer enlarged slightly. There days after injury, the edema of retinalbecame evidently, vacuolated charges could be seen in slight ganglion cells,the arrangement of inner and outer nuclear layer cells were closed and moreregular than that of control group. Seven days after injury, edema of retinalalleviated mote obviously than that of control group, the arrangement of cellswas regular. Fourteen days after injury, the retina was still edematous thearrangement of cells was regular, the thickness of retina closed to normalgroup. The change of ganglion cell shape and number at every time point, theextent of retina edema were both alleviated more significantly than that ofcontrol group.2The results of immunohistochemical.2.1The expression of IGF-1in retinal tissueThe expression of IGF-1was poor positive in normal retina tissue and themean OD value was0.0716±0.0035.Compared with normal group, theexpression of IGF-1in control group enhanced after1day,3day and7day ofinjury(p<0.05), the mean OD value respectively were0.0921±0.0010,0.1303±0.0044,0.1502±0.0054.The experiment of IGF-1began to decrease atthe14th day and the mean OD value was0.0750±0.0025, the expression ofIGF-1in the two group had no significant difference (p>0.05).The expressionsof IGF-1in treatment group were significantly obvious than that of controlgroup at every time point after injury and there was significant differencebetween the two group(p<0.05), the mean OD value were0.1181±0.0066,0.1999±0.0064,0.2855±0.0074,0.1809±0.0075,0.1041±0.0027.2.2The expression of AQP4in retinal tissueThe expression of AQP4in normal retinal tissue was poor positive andthe mean OD value was0.0782±0.0011. Compared with the normal group, theexpression of AQP4in control group began to increase after one day of injury,reached the highest level at the third day, began to decrease at the7th day and closed to normal level at the28th day, the mean OD value respectively were0.1946±0.0095,0.4324±0.0078,0.3812±0.0042,0.2066±0.0089. Except forthe28th day, the expressions of AQP4in control group at all the other timepoints were significantly higher than that of normal group(p<0.05). Except forthe28th day the positive expressions of AQP4in treatment group at the firstday,3th day,7th day and14th day were significantly lower than that of controlgroup(p<0.05), the mean OD value respectively were0.1199±0.0044,0.3205±0.0058,0.2306±0.0145,0.1341±0.0025.Conclusions：1The expression of AQP4in normal retinal tissue is poor positive and itincreases after incomplete injury of the optic nerve. AQP4participate theprocess of incomplete injury of rats optic nerve.2The expression of IGF-1in normal retinal tissue is poor positive and itincreases after early incomplete injury of the optic nerve. IGF-1participate theprocess of incomplete injury of rats optic nerve.3Progesterone could decrease the expression of AQP4in the rat retinal tissueafter the incomplete injury of optic nerve.4Progesterone could increase the expression of IGF-1in the rat retinal tissueafter the incomplete injury of optic nerve.5Progesterone could promote the regeneration and repair of retina cell.