To Investigate Action Of NGF To Retinal Cells' Apoptosis On Form Deprivation Myopia In Guinea Pig

Myopia is one ametropia and the morbidity is the highest in the world. The morbidity of myopia increases constantly and the age of onset is younger than before and it will have progress when it occurs.So it becomes a very serious public progrem in our global.The prevention and cure of myopia has been included one of the plan which to prevent the blindness by the world health organization(WHO)Since the eraction of the model of the form deprivation myopia by Wiesel and Raviola in 1977 years. We have got a some congnition in myopia by this method.That's the regulation of the sclera's growth mainly by the partly retinal technique in the form deprivation and there are many neurotransmitters in the retina.The neurotransmitters could be changed by form deprivation and it is one factor to form the form deprivation myopia. The eraction of the model of the form deprivation myopia is a great progress in the studying of myopia. We have got a juiner congnition in myopia by this method. It provides a valuable information and thought for the theory studying of myopia.Pathological myopia is a common growing blind disease.The retinal photosensory cells become fewer when it occurs.Apoptosis may one reason to this changes.Cell apoptosis is a procedure cell death controled by genes to maintain the stabilization of the internal environment.Cell apoptosis and cell death is different.Cell apoptosis is not a passive course but an active course.It includes a serious of gene's activation,expression and regulation. It is not a damage in the pathologcal condition,but an active death to adapt the change of the environment. The researchs have proved that cell apoptosis is a course provocated by a serious of death informations and Caspase is a key factor to the cell apoptosis which has been proved by more and more experiments.During the apoptosis stage,the enzyme of caspase-3's targets: Asp-28-ser-29 and Asp-175-ser-176 have been actived after they have been dissected and change to two subunits: 17ku and 12ku and the DNA has been dissected specially by the actived caspase-3 and lead the poly-ADP ribose polymerase and DAN dependented protein kinase to deactive and the caryotin's concentration,the nuclease's activation result in the cell apoptosis.Nerve growth factor (NGF)is a kind of protin extensive occurrence in many kinds of animal.It could not only maintain the survival of the sensory neuron and the growth of the neurofibr, but have a special function of increasing the arborization of the neurone and conservation the differentiated neurone in the individual development and raise the expression of the sensory neuron. So we have a thought that we could inject NGF into the form deprivation eyes' vitreous body during the time that the course of forming deprivation myopia in the guinea pigs to find the function of NGF on the course of forming deprivation myopia in the guinea pigs.Thereby to provid a new method on the prevention and cure myopia.Methods50 neonatal genipa pigs of one week old were divided randamly into group A ,B and C and were monocularly deprived(MD)of pattern visual by transpartant eye shield of right eye .Each group genipa pigs were raised in different cages and the bait and water were no confined to them.The lighting came from the daylight lamp and the lighting and the darkness were both 12 hours.In group l(n=10)no drug was used ,while guinea pigs in group 2(n=20)and 2(n=20)were received a series of introvitreal injection of NGF5 ug(1μg/μl ) and salin vehicle5μl with MD after 11 weeks when they were anesthetized. Once two days and total three times. The guinea pigs' diopter were measured by a practised optometrist after full mydriasis when the guinea pigs were raising after 12 weeks,meanwhile the axle length(the length from the topic of the cornea to posteria pole of the boundary of the vitreous and the retina.The mean of 5 measurements was the result) were measured byA ultrasonic when the guinea pigs' were received a surface anesthesia.The eye ball were extracted and immobilizated ,embeded ,sliced and undertake immunhistochemistry strickly by the instruction to examine the expression of Caspase-3 and we used the TUNNEL technique to find the cell apoptosis in the retina.ResultsThe retinal cell in inner nuclear layer and outer nuclear layer of the form-deprivation eye reduced compare with the contral eye.The alignment of the retinal cell in form-deprivation eye was loose.The difference of retinal ganglion cell was not manifest in light microscope not because the ganglion cell was monolayer but it was sparse.A relativity myopia was received on the form deprivative eyes contrast with the other eyes in each group.The axle length of the form deprivative eye was extended in each group. The axle length in group 1 was the longest ,the mean was 10.02±1.26 mm; On the contrary, the axle length in group 2 was the shortest, the mean was 9.84±1.17 mm and the axle length in group 3 was9.86±1.11 mm. The axle length showed a significient difference on the form deprivatived eyes and the other eyes in each group.It showed no significient difference between group 2 and group 1,group 2 and group 3 and there was no significient difference on the form deprivatived eyes in group 2 and group 3.The form deprivative eyes' diopter in group 2 is -9.25+1.80D .It showed no significient difference between group 2 and group l,group 2 and group 3,and there was no significient difference on the form deprivatived eyes in group 2 and group 3.In each group,the diopter of form deprivation eyes showed a significient difference with the other eyes.While the apoptosis rate of the retina in group 2 was 1.41±0.42 (单位% ) and in group 3 was 2.03 + 0.73 (单位%) and in group 1 was 2.14 + 0.58 (单位%) the apoptosis rate showed a significient difference between group 2 and group 3 ,group 2 and group 1.Otherwise we used lusinomity to respond the expression of Caspase-3. It showed a significient difference between group 2 and group 3.The expression of Caspase-3 and the rate of retinal cell apoptosis is associative.ConclusionThe retional cell apoptosis could be partly block by NGF and NGF can protect the retina of form deprivation myopia in guinea pigs.