Study Of The Role Of BDNF During The Forming And Development Of Form Deprivation Myopia

Myopia is a commonly and frequently encountered disease in clinics. It brings a lot of inconvenience to people's lives, works and studies. During the study history of more than 200 years, the form deprivation theory is a research hotspot. Since the form deprivation model was successfully established, many scholars have carried out plenty of experiment researches on the biochemistry, pathology and pathogenesis of form deprivation myopia(FDM). There is still no satisfactory explanation to the pathogenesis of FDM. Recent studings showed that various neurotransmitters and biological molecules on the retina were concerned with the growth of eyeball and played roles in the course of forming of FDM. Brain derived neurotrophic factor (BDNF) is one member of the neurotrophins and becomes more and more important to people. Studies showed that monocular deprivation decreased BDNF messenger RNA level in the visual cortex contralateral to the deprived eye and BDNF level of RGCs of the deprived eye. Exogenous supply of BDNF can prevent the effects of monocular deprivation. These studies suggested that BDNF participated in the development of FDM and played an important role, but the particular mechanism was not clear. We established the chick model of FDM, and continued to raise chicken removed the translucent goggles for two weeks. Retinal level of BDNF was assayed by immunohistochemical method. We observed the changes of BDNF expression on the form deprived chicken retina informing and recovery of FDM in order to further investigate the pathogenesis of BDNF participating in the development of form deprivation myopia.Materials and MethodsThirty two healthy male newborn hailan chicken were selected. All the right eyes underwent form deprivation with translucent goggles, and the left eyes were used as control. Raise chicken indoor and maintain temperature in 28 癈~32 癈, natural diurnal rhythm. All chicken were randomly divided into four groups. A and B groups were deprived for one and two weeks respectively. After being deprived for two weeks, C and D groups were removed the translucent goggles and continued to be raised for one and two weeks respectively. The refractive state of each group was determined by means of streak retinoscopy (without cycloplegia) on designed time. The eyes were extracted and the axial length and equatorial dimension were measured by vernier caliper as quickly as possible. Routine fixation, dehydration, paraffin embedding were done and 4/um paraffin sections were taken. Routine hematoxylin-eosin staining were done and morphological changes was detected by light microscope. We measured theexpression level of BDNF on the chicken retina using streptaridin-peroxidase immunohistochemical method.Results1. Monocular deprivation for one week could lead to myopia. The refraction showed significant difference between the deprivation eye ( - 9.88 0.95 D) and the control one (0. 75 0. 46 D) (P< 0.001 ). The longer the eyes were occluded, the more severe the myopia was. When occluded for two weeks, the refraction of the deprivation eye was (-17.16 0.67 D) and the control eye was (0.56 0.32 D) . There was significant difference between them (P< 0.001). After goggles removed the lelve of myopia of previously deprivation eye decreased. The longer the translucent goggles were removed, the more lightened the myopia was. Two weeks after goggles removed, the refractions of the deprivation eye and the control eye were (-8.13 0.61 D) and (0.13 + 0. 35 D) and there was significant differencebetween them (P< 0.001).2. Monocular deprivation for one week could make the axial length and equatorial dimension of the deprived eye obviously increased. There was significant difference between the deprived eye and the control eye (P< 0.001 ). Along with time prolonging, the axial and equatorial dimension of boths eyes increased continuously. When occluded for two weeks, the difference of the axial and equatorial dimension was significant between both eyes (P< 0.001 ). After goggles r...