Protective Effect Of Ginkgo Biloba Extract On Muller Cells From Oxidative Damage

ObjectTo study the protective effect and mechanism of Ginkgo biloba extract(EGb) on oxidative stress of human retinal induced by AS2O3.MethodsThe human retinal Muller glial cells were established by5mg AS2O3/L, EGb was then divided into5mg/L,10mg/L and20mg/L3concentration gradients role in Muller cells. Cell viability was detected by MTT assay. Reactive oxygen species (ROS) levels of intracells were measured by CMH2DCFDA fluorescent probe. Caspase-3、 Nrf2and HO-1mRNA level measured by RT-PCR. The protion expression levels of Nrf2and HO-1were detected by Western Blot.Results1. The result of cell viability showed that the cell viability in each group was enhanced as the EGb concentration increased (F=163.57, P<0.0001).2. The results of ROS test showed that the ROS level was lower when EGb concentration was higher(F=4013.61, P<0.0001).3. The result of Caspase-3mRNA test showed that Caspase-3mRNA expression was lower when the concentration of EGb was higher (F=299.72, P<0.0001) 4. The result of Nrf2mRNA test showed that Nrf2mRNA expression was higher when the concentration of EGb was higher (F=236.96,P<0.0001)5. The result of HO-1mRNA test showed that HO-1mRNA expression was higher when the concentration of EGb was higher (F=242.62,P<0.0001)6. The expression of Nrf2protein in nucleus of Muller cells showed that the higher concentration of EGb was same as a higher expression of Nrf2protein (F=7271.72, P<0.0001); but the level of Nrf2protein in the cytoplasm in each group had no change when the concentration of EGb was increased (F=15.42, P=0.40)7. The expression of HO-1protein in nucleus of Muller cells showed that the higher concentration of EGb was same as a higher expression of Nrf2protein (F=13421.3,P<0.0001); but the level of HO-1protein in the cytoplasm in each group had no change when the concentration of EGb was increased (F=0.51,P=0.7336)Conclusions1. The cellular apoptosis induce by ROS produced by As2O3can be inhibited by EGb. The mechanism may be related to regulation of Caspase-3mRNA expression and intracellular antioxidant source of transcription factor-Nrf2expression.2. The experiment found that the use of EGb in different concentrations of oxidative stress in Muller cells, as the concentration increases, the test results show that increasing Nrf2gene and protein expression levels, both of there is a significant positive inter-correlation. The differences were statistically significant (P<0.05). The experiment found that the use of EGb in different concentrations of oxidative stress in Muller cells, as the concentration increases, the test results show that increasing HO-1gene and protein expression levels, both of there is a significant positive inter-correlation. The differences were statistically significant (P<0.05). Therefore believe that Ginkgo biloba extract may be through Muller cell Nrf2/ARE signaling pathways play a protective role on oxidative stress status. 3. The results showed that the expression level of Nrf2and HO-1protein in the nucleus is concerned with EGb concentration, while the expression level of Nrf2protein in the cytoplasm has no significant difference; it shows that the central regulation protection mechanism of EGb on Muller cell oxidative stress injury is in the nucleus.