Effects of 15-Hydroperoxy Arachidonic Acid and Non-Purified Hydroperoxides from Arachidonic Acid to Rabbit Blood Vessels
1980 Volume 17 Issue 1 Pages 63-70
Details
1980 Volume 17 Issue 1 Pages 63-70
Effects of 15-hydroperoxy arachidonic acid (15-HPAA) and non-purified hydroperoxides (HPO) from arachidonic acid (AA) to blood vessels were observed in rabbits.
15-HPAA was converted from AA (100mg/50ml Na2CO3) by incubation with lipoxidase (50mg/750ml botate buffer) at room temperature for 10 minutes. and purified by thin layer plates (silica gel).
HPO was made from that was radiated by ultraviolet lamp (250W) for 8-10 days. HPO was quantified as the malondialdehyde (MDA) value by TBA reaction. and was used in concetration of 126 nmoles MDA/ml. With aggregometer in vitro, 137μM (41.7μg/ml) of AA aggregated markedly rabbit platelets by 75% in light transmittance, however the same dosages of neither 15-HPAA or HPO aggregated. The effects to microcirculation were observed by evans blue leakage in the skin after subcutaneous injection of 15-HPAA. or histamine. The leakage was graded by spectrometry (620nm) after dye extraction from the skin spot. The optimal density was 0.05±0.004 by 10μg, 0.18±0.024 by 10μg and 0.38±0.017 by 500μg of 15-HPAA, and 0.16±0.009 by 1μg and 0.22± 0.014 by 10μg and 0.34±0.027 by 100μg of histamine as a control study.
Effects to the aortic wall were evaluated by edema in the intima and media in histology. The aortic wall showed marked edematous arterial changes 30 minutes after intravenous injection of 15-HPAA (3mg/kg) or HPO (5mg/kg). The grade of edematous changes were 68.3±4.30% by 15-HPAA, and 70.8±11.46% by HPO and 40.8±6.77% by pretreatment of phthalazinol (5mg/kg i.v.).
Both responses by 15-HPAA and HPO were not different significantly. and the edematous changes induced with 15-PHAA was suppressed significantly by pretreatment of phthalazinol.
These results suggested that the vascular permeability increased dose-dependently in both microvessels and aortic wall by 15-HPAA and it seemed to be caused by a cytotoxic effect.
It is probable that 15-HPAA might accelerate atherogenesis by marked increase of aortic wall permeability.
