Effects of a Rho kinase inhibitor on the sequential expression of ICAM-1, HIF-1α, Bcl-2 and caspase-3 in the retina of rats with oxygen-induced retinopathy

Abstract

Abstract. The aim of the present study was to evaluate the effects of blocking the Rho kinase pathway on non-perfused regions and angiogenesis in the retina of rats using a rat model of oxygen-induced retinopathy (OIR) by observing the sequential expression of intercellular adhesion molecule-1 (ICAM-1), hypoxia-inducible factor-1 (HIF-1), B-cell lymphoma/leukemia-2 gene (Bcl-2) and caspase-3 mRNA following the administration of the Rho kinase inhibitor, fasudil (FSD). A total of 240 newborn rats were randomly divided into a normoxia control (N) group, a hyperoxia (H) group and a H + FSD (HF) group. The rats were sacrificed, and the eyes were enucleated from postnatal day (P)12 to P21. Samples were prepared for retinal flat mounts, mRNA and protein quantification. On P14, a higher number of circuitous retinal veins was observed in the H group compared with the HF group. In the HF group, the avascular area was significantly reduced compared with the H group on P18 (P<0.01). In the HF group, the mRNA expression of Bcl-2 was significantly increased on P15 compared with the N and H group (P<0.01). On P15 and P17 in the H group and on P13 in the HF group, the mRNA expression of ICAM-1 was significantly increased compared with the other groups (P<0.05). In the H and HF group, the expression of HIF-1α was significantly increased on P12 compared with the N group (P<0.05). On P19 and P21, HIF-1α expression was significantly increased to a maximum level in the HF group compared with the H and N group (P<0.01). In conclusion, these results suggest that FSD inhibits the expression of ICAM-1, assisting in the release of Bcl-2, suppressing caspase-3. In the HF group, the retinal flat mounts revealed that FSD had a vasorelaxant effect. On P18, a double-layered retinal vascular network was formed, and the number of non-perfused regions was significantly reduced. However, the late-phase peak expression of HIF-1α resulted in an inevitable increase in vascular endothelial growth factor expression and further accelerated neovascularization and vascular reconstruction in the immature retinal model.

AMA0428, A Potent Rock Inhibitor, Attenuates Early and Late Experimental Diabetic Retinopathy

“…These results are in line with previous reports, which employed the reference ROCK inhibitor Y-27632. 27,63 Indeed, the Rho/ROCK pathway, an essential mediator of NFκβ, is known to play a critical role in diabetic retinal microvasculopathy, since ROCK inhibition protects the vascular endothelium by blocking neutrophil adhesion. 27,77 Unfortunately, Western blot data could not confirm a similar reduction in ICAM-1 levels at 3 or 7 days after AMA0428 administration at 7 weeks post DM onset, as compared with vehicle-treated retinas (data not shown).…”

“…32 During vascular injury and as a result of the coagulation cascade, thrombin is formed leading to intravascular coagulation, 30,31 but also ICAM-1 expression. 27 Because of the essential role of NF-κβ in mediating thrombin-induced transcription of ICAM-1 in ECs 27 and the reported link between activated ROCK and the release of RelA/p65, 63 we investigated whether the ROCK inhibitor AMA0428 could intervene with thrombin-induced NF-κβ activity in HUVECs. Therefore, a cell-based ELISA was performed to measure phosphorylated RelA p65, a member of the NF-κβ family.…”