高眼压对视神经轴突损害的定量微机图像分析

将健康家猫２８只共５６眼随机分成７组，除正常对照组外，其余６组４８眼制成高眼压模型。用荧光眼底血管造影观察正常眼压及高眼压持续２４ｈ及４８ｈ的眼底血管荧光图像，用微机图像分析系统定量测定视神经轴突直径、总数及占视神经面积百分率；透射电镜观察视神经轴突超微结构。结果显示高眼压持续２４ｈ及４８ｈ的猫眼底荧光血管造影与正常眼压时无明显差异，而高眼压持续２４ｈ后，视神经轴突即可出现明显改变，其直径增大、数量减少、占视神经面积的百分率降低（Ｐ＜０．０５）；高眼压持续时间越长轴突损害越严重（Ｐ＜０．００１），两者呈显著相关。透射电镜检查发现高眼压持续２４ｈ后，视神经轴突的超微结构较正常有明显改变。高眼压持续时间延长，改变越明显。提示高眼压是造成视神经轴突损害的重要原因，因此对青光眼的治疗应尽早采取积极地降低眼压措施。

QUANTITATIVE IMAGE ANALYSIS STUDY OF OPTIC NERVE AXONS DAMAGE BY ELEVATED INTRAOCULAR PRESSURE

health cats were divided to 7 groups(56 eyes,each group 8 eyes) randomization.Except control group, other 6 groups(48 eyes) were performed elevated intraocular pressure(IOP) models, Ocular fundus fluorecent angiography was performed on normal cats eyes and elevated IOP cats eves models which elevated IOP continuous time was 24h and 48h.Quangtitative analysis of the optic nerve axons diameter,total numbers and percent on optic nerve area were utilised by computer image analysis system.Ultrastructure of optic nerve axons in normal cats eyes and elevated IOP cats eyes models was observed by TEM.Results showed that the ocular fundus fluorecent angiography hasn't significantdifference between normal IOP group and elevated IOP models group after elevated IOP was continued 24h or 48h.When the elevated IOP was continued 24h, however,the optic nerve axons were appeared obvious change,which it were included the axons diameter enlargement,reduction of axons total numbers,the percent of axons in optic nerve area was decrease(P<0.05).The more continuous time of elevated IOP.the more serious does the optic nerve damage(P<0.001),both presented significant correlation.The ultrastructure of axons in elevated IOP continued 24h was presented obvious pathologic changes,and the more continuous time of elevated IOP,the more serious does the pathologic changes of axons ultrastructure.It is concluded that the elevated IOP is an important michanism of optic nerve damage for glaucoma,especially elevated IOP continuous time play an important role in extent of optic nerve damage,So,in order to prevent optic nerve damage for glaucoma ought to reduce elevated IOP to normal level as early as possible.