Protective Effect Of Qing-Gan-Li-Shui Formula On Retinal Ganglion Cells In A Rat Experimental Chronic Intraocular Hypertension Model

Objective: Glaucoma is mainly treated by lowering intraocular pressure(IOP).Although some patients’ intraocular pressure has been reduced to normal range and some optic nerve protective drugs have been used,the damage of visual function continues,and the apoptosis of retinal optic ganglion cel s(RGC)caused by subsequent pathologica l changes cannot be prevented.Qing-Gan-Li-Shui Formula(QF),a traditional Chinese medicine,has been used for many years and has good clinical effect.Previous experiments have proved that QF can inhibit the apoptosis of RGC induced by chronic glaucoma.In order to verify the therapeutic effect of QF on apoptosis of retinal ganglio n cel s in rats with chronic intraocular hypertension,we established a rat model of chronic intraocular hypertension by injecting superparamagnetic iron oxide(SIO)beads into anterior chamber,and to explore its protective effect and possible related mechanism.Methods: 1.125 rats were randomly divided into blank control group,COH group(COH: chronic intraocular hypertension),low concentration QF group,medium concentration QF group and high concentration QF group,25 rats in each group.In addition to the blank group,the rats in each group were injected with SIO beads into the anterior chamber,and the intraocular pressure was continuously elevated by blocking trabecular meshwork.2.Rats with chronic ocular hypertension induced in the treatment group were given QF Decoction water solution at the same dosage(according to the original drug dosage: 5 ml/kg in the low concentration group,10 ml/kg in the medium concentration group and 20 ml/kg in the high concentration group),once a day for 28 days.Intraocular pressure was measured before operation(d0),3 days,7 days,14 days,21 days and 28 days after operation.3.A group of 6-7 rats were sacrificed on 7,14,21 and 28 days after operation.The expression of caspase-3,Bax and Bcl-2 protein was determined by Western blot after collecting all retinal tissues.Results: 1.By injecting SIO into the anterior chamber,the IOP values of each model were determined after 7 days.The IOP values of each model lasted steadily for more than 12 mm Hg until the 28 th day,and the model was successfully made.2.The intraocular pressure of SD rats in the treatment group decreased 14 days after operation compared with that in the model group(P < 0.001),and the treatment effect of the medium dose group was the most obvious.3.The expression of Bcl-2 protein increased(P < 0.001),the expression of Bax protein decreased(P < 0.001),and the ratio of Bax/Bcl-2 decreased in each group.The relative effect of medium dose group was the most obvious at 21 days of treatment.The expression of Caspase-3 in the treatment group was significantly inhibited only at low doses,but the other differences were not statistically significant.Conclusion: QF can reduce IOP and protect RGC in chronic glaucoma rats induced by SIO.Among 1/2 concentration,normal concentration and 2 times concentration,normal concentratio n has the best effect on IOP reduction.Its anti-apoptotic mechanism is through increasing Bcl-2 expression and inhibiting Bax expression in cells.