An investigation of changes in ocular blood flow in rabbits with long-term hyperhomocysteinemia using color doppler ultrasonography
Sertac Hanedan ONAN,
Muammer Hakan POYRAZOGLU
Aim: Hyperhomocysteinemia was induced in rabbits using methionine. Ocular blood flow changes were examined by color Doppler ultrasonography (CDU).
Materials and methods: Fifty New Zealand rabbits were divided into 5 groups. Groups 1-4 received one of the following chemicals: methionine only, methionine plus vitamin B6, methionine plus vitamin B12, or methionine plus folic acid. Controls received no chemicals. Serum homocysteine levels were measured on treatment days 1 and 60. Orbital vessels were examined by CDU on day 60.
Results: In the 4 study groups, homocysteine levels were significantly elevated on day 60 compared to the levels on day 1 (P < 0.05). Elevations of homocysteine levels in group 1 were greater than those of groups 2 and 4 on day 60 (P < 0.05). When results of ocular blood flow changes were compared, no statistically significant difference was found based on flow velocities in the ophthalmic artery. Measurements from the ciliary artery revealed a statistically significant decrease in flow velocity in the study groups (P < 0.05).
Conclusion: Using CDU, we found that flow velocities in the ciliary artery were decreased. This condition is attributed to atherosclerotic and thromboembolic alterations of the ocular vessels due to hyperhomocysteinemia.