Effect of intravitreal bevacizumab and fasudil on superoxide dismutase, tumor necrosis factor alpha, nuclear factor kappa b, vascular endothelial growth factor and caspase 3 levels in experimental diabetes mellitus model

DM is the most common cause of visual loss in patients aged between 20 and 65 years. The exact factors responsible for etiopathogenesis of the disease is not known despite many studies done. Hyperglycemia in diabetic patients results in degeneration of retinal capillaries, loss of endothelial pericytes, endothelial proliferation, thickening of basement membrane and occlusion. It is well known that toxicity, inflammation, angiogenesis and apoptosis play an important role in the development of diabetic retinopathy and its complications. In the present study, the levels of SOD, TNF alpha, NF-kB, VEGF and caspase 3 were assessed in rabbits that had experimentally induced DM and intravitreal injection of bevacizumab and fasudil, and results were compared with healthy controls rabbits. The study population composed of 6 healthy rabbits (Group 1), 6 rabbits with experimentally induced diabetes mellitus (Group 2), 7 rabbits with experimentally induced DM to which intravitreal bevacizumab were administered (Group 3) and 7 rabbits with experimantally induced DM to which intravitreal fasudil were administered (Group 4). An intravitreal injection of 1.25 mg/50 µL bevacizumab in the right eye of rabbits in Group 3 and intravitreal injection of 180 µM/50µL fasudil in the right eye of rabbits in Group 4 were administered on day 21 after induction of DM. Studied eyes of rabbits were enucleated three days after the intravitreal injection. SOD, TNF alpha, NF-kB, VEGF and caspase-3 levels were determined using ELISA method. Differences between study groups were assessed using the Kruskal-Wallis test and Mann-Whitney U test with Bonferroni correction. Kruskal Wallis test revealed statistically significant difference in VEGF and caspase-3 levels betwen groups (p=0.005 and p=0.013, respectively), but SOD and TNF alpha levels did not differ between groups (p=0.135 and p=0.792, respectively). NF-kB level was below the detectable range for all groups. It was found that VEGF levels were significantly lower in Group 1 and Group 3 than in Group 2 using Mann-Whitney U test with Bonferroni correction (p=0.004 for both comparison). There was no statistically significant difference between other groups with regard to VEGF levels (p value was ranging between 0.015 ile 0.886). Although the p values of caspase 3 level was 0.015 for group 1 and group 4, 0.038 for group 2 and group 3, 0.018 for group 3 and group 4, these p values remained above the threshold p value of 0.0083, which is statistically significant level for second stage tests. In conclusion, intravitreal administration of bevacizumab decreased both VEGF levels, which plays role in angiogenesis and caspase 3 levels, which plays role in apoptosis. Although not as much effective as bevacizumab, fasudil had a beneficial effect on VEGF levels, but significantly increased caspase 3 levels when compared with other groups.