Abstract
Purpose: :
To investigate the effects of Rho kinase inhibitors, fasudil and K115, on retinal microcirculation in cats.
Methods: :
Same concentration of fasudil (n=5), a novel Rho kinase inhibitor K-115 (n=5), or vehicle (PBS; n=5) was injected intravitreously. The vessel diameter and blood velocity were measured simultaneously in the first-order retinal arterioles by laser Doppler velocimetry (CLBF model 100, Canon); the retinal blood flow (RBF) was calculated. The measurements started 15 minutes before the injection, and were performed every 10 minutes for 2 hours after the injection.
Results: :
In the PBS group, vessel diameter, blood velocity, and RBF did not differ significantly from the pre-injection level. In the fasudil group, vessel diameter and blood velocity did not change significantly. RBF tended to increase (P=0.09) but there was no statistically significance. At 120 minutes in the K-115 group, vessel diameter did not change significantly, but blood velocity (33.3±8.0%, P<0.001) and RBF (32.5±7.9%, P<0.001) significantly increased from the pre-injection levels. The blood velocity (P<0.01) and RBF (P=0.02) were significantly increased in the K-115 group compared with those in other groups.
Conclusions: :
Our data showed that intravitreal administration of a novel Rho kinase inhibitor K-115 increased blood velocity and RBF in cats. These finding indicate that the increase in blood velocity in the K-115 reflect a dilation of the downstream from the measured vessels.
Keywords: blood supply • retina