Neuroprotective Effect Of Total Panax Notoginseng Saponins On Retinal Neuron Injury In The Rats With Chronic Ocular Hypertension

PARTⅠ:Objective To investigate if total panax notoginseng saponins (tPNS) has a neuroprotective effect against chronic ocular hypertension induced neuron death in RGCL.Methods 42 healthy SD rats were randomly divided into seven groups. 6 animals were in normal control group,6animals were in normal treated group (tPNS200mg/kg) The others were cauterized three episcleral vessels and were divided as experimental groups: groupA (50mg/kg), groupB(100mg/kg), groupC(150mg/kg), groupD (200mg/kg)and group treated by normal saline.Rat were sacrificed on schedule.Flat preparation of whole retinas were stained with 0.5%cresyl violet and neuron counting in RGCL from both eyes of each rat were performed to evaluate neuron loss.Results1.Neuron counting from RGCL of normal control group:The mean of neuron counting of RGCL in the right eye wa(s3477.0±127.6)/mm2 and(3488.1±91.3)/mm2 in the left eye .There was no significant difference between the right eye and the left eye of normal control group(P﹥0.05).neurons of RGCL were divided into three groups according to their diameter as: small(≤8μm),medium(8～14μm), large(≥14μm) size. The mean of neuron counting of RGCL in large, medium and small were (1046.7±114.3)/mm2,(2086.2±121.6)/mm2,(344.1±43.3)mm2。2. Neuron counting from RGCL of normal treated group: The mean of neuron counting of RGCL in the right eye was (3456.5±109.5)/mm2 and (3466.8±113.9)/mm2 in the left eye . 3. Neuron counting from RGCL of treated group A: The mean of neuron counting of RGCL in the right eye was (2161.6±101.1)/mm2 and (3523.1±116.5)/mm2 in the left eye . Neuron counting from RGCL of treated groupB: The mean of neuron counting of RGCL in the right eye was ( 2215.4±91.3 ) /mm2 and (3505.5±121.3)/mm2 in the left eye . Neuron counting from RGCL of treated groupC: The mean of neuron counting of RGCL in the right eye was(2456.5±98.1)/mm2and (3506.5±128.7)/mm2in the left eye . Neuron counting from RGCL of treated groupD: The mean of neuron counting of RGCL in the right eye was (2236.0±86.3)/mm2 and (3467.5±135.7)/mm2in the left eye .There was no significant difference between normal control group and normal treated group either in the right eye or in the left eye(P﹥0.05). There was no significant difference between normal control group and experimental groups(P﹥0.05).4. Neuron counting from RGCL of group treated by normal saline: The mean of neuron counting of RGCL in the right eye was ( 2166.7±101.9 ) /mm2and (3463.9±121.2)/mm2 in the left eye .There was significant difference between group C and normal saline group (P﹤0.05).Conclusion1. tPNS has no effect on neuron counting of RGCL when administered alone in normal rats.2. tPNS has partial protective effect on chronic ocular hypertension induced neuron death in RGCL in the rat.3. Neurons with laegger diameter were more sensitive to elevated IOP,in a similar fashion to the pattern of RGC loss seen in glaucoma. PARTⅡ:Objective To observe the protective effect of total panax notoginseng saponins(tPNS)on the activity of retinal ganglion cells(RGCs)in SD rats with elevated intraocular pressure(IOP).Methods Tweleve healthy SD rats were cauterized three episcleral vessels and were divided into two groups (tPNS treated group including normal IOP and elevated IOP, untreated group including simple normal IOP and elevated IOP)with 6 rats in each group. tPNS was irrigated into the stomachs of rat in treated group on the 7th day after formation of elevated IOP.The rat eyes were enucleated and made into eyeball samples after 40 days.The paraffin-embedded slides were stained with silver staining for nucleolar organizer region(AgNOR) to observe stained grains in RGCs nucleus.Results1.Stained grains in RGCs nucleus of the group A i(s1.37±0.11)/mm2,and Stained grains in RGCs nucleus of the group B is (1.94±0.23)/mm2, There was significant difference between group A and group B(P﹤0.05).2.compared with those of the two normal IOP subgroups, and the statistical significance was found(P<0.05). But stained grains in RGCs nucleus of the ocular hypertension with tPNS treated subgroup were more than those of the simple ocular hypertension eyes(P<0.05).Conclusion1. Cauterizing the episcleral vessels to build chronic elevated IOP can result in the decrease of stained grains in RGCs nucleus.2. tPNS may have partial protective effect in RGCs activity of ocular hypertension.