The Effect Of Immunization With Copolymer-1 On The Retinal Ganglion Cells And The Glia In Chronic Elevated Intraocular Pressure Rat Models

AIMs:1. To detect the normal intraocular pressure (IOP) and establish reliable chronic elevated intraocular pressure (EIOP) rat models.2. To establish reliable copolymer-1(COP-1)-immunized chronic EIOP rats models.3. To observe the variation of apoptosis of retinal ganglion cells (RGCs) in chronic EIOP rat models: control rats, placebo-immunized EIOP rats and COP-1- immunized EIOP rats.4. To inspect the expression of the MHC-II antigen in the glia of the retina of chronic EIOP rat models: control rats, placebo-immunized chronic EIOP rats and COP-1- immunized chronic EIOP rats.5. To examine the variation of IL-6R in chronic EIOP rat models: control rats, placebo-immunized chronic EIOP rats and COP-1- immunized chronic EIOP rats.METHODS:1. Examine the IOP of the normal rats with handheld tonometer (TONOPEN-XL).Chronic EIOP rat model is establish by cauterizing episcleral venous to block the reflux of aqueous humor.2. The immunized rat model is establish via i.p injection of COP-1 into hind feet pads.3. The apoptosis of the RGCs of each group are examined by TUNEL staining.4. The expression of the MHC- II antigen in the glia of the retina is detected by immunohistochemical staining and analysis of the image.5. The expression of the IL-6R on RGCs is detected by immunohistochemical staining and analysis of the image.RESULTS:1. The IOP of normal rats fluctuates from 1. 06 to 1. 99 Kpa(l. 56 + 0.25 Kpa) at daytime and from 1.73 to 2.66 Kpa (1. 86 + 0. 23 Kpa) at nighttime respectively. The IOP is prominently elevated by cauterizing the two veins of episclera, especially in 1 hour after the surgery. The ultimate IOP is stabilized at 4 Kpa or so.2. The specific antibodies of Cop-1 were identified in blood serum in Cop-1-immunized chronic EIOP rats 8 weeks after autoimmunization induced by Cop-1.3. The amount of the RGCs with positive results of TUNEL staining is the least in control rats (24. 3 + 3. 12/120Wn) and the most in placebo-immunized chronic EIOP rats(44.0+4.54/120um) and in-between in COP-1-immunized chronic EIOP rats (35. 5 + 3. 30/120um) The differences between each group are all statistically significant (P<0.05) .4. The expressions of the MHO II antigen in the glia of the retina of each group differ greatly, with negative expression in control rats and positive expression in certain layers of placebo-immunized chronic EIOP rats and COP-1- immunized chronic EIOP rats. The gray scale of OX-42 in placebo-immunized chronic EIOP group(144. 6 + 4. 35) is lower than that in the COP-1- immunized chronic EIOP group (174.8 + 7.13). The gray scale of OX-6 in placebo-immunized chronic EIOP group (123.6 + 8.94) is lower than that in the COP-1- immunized chronic EIOP group ( 182.62 + 6.18 ) , there are statistically significant difference between the two groups (P<0. 05) .5. The expressions of IL-6R among the three groups are positive, which are most notable in the retina ganglion cell layer. The expression of control group is significantly weaker than those of the placebo-immunized EIOP group and COP-1- immunized EIOP group. The expression of the placebo-immunized EIOP group is significantly weaker than COP-1- immunized EIOP group. The results of the image analyzing reveal that the grayscale of the differences between each group(the control group' gray scale is 201. 09 + 3. 72, the placebo-immunized EIOP group' gray scale is 182.62 + 6.18 and COP-1-immunized EIOP' gray scale is 166.21 +6. 54) are statistically significant (P<0.05). CONCLUSIONS:1. The baseline IOP of normal rats is characteristic of day-night rhythmicity with manifestation of elevation at nighttime and decrease at daytime. Blocking the reflux via cauterizing episcleral venous is an effective method to establish reliable chronic EIOP model. This method can ideally mimic chronic EIOP model and avoid serious syndromes at the same time. However, an effective trial is required because the energy of the cauterizing can not be quantitatively evaluated.2. Immunization by injection...