The Effect of Topical PGE4 (Prostaglandin E1) Analogue on Angiogenesis in the Hairless Mouse

ABSTRACT

An important aspect of plastic surgery is skin flap survival. Among the prostaglandins, PGE4 is used clinically to improve peripheral circulatory disturbances due to its action of augmenting blood flow by vascular smooth muscle relaxation and its strong inhibitory action of platelet aggregation. Clinically, many investigators found that the effect of PGE4 was prolonged for a long period even after short-term application. So a new hypothesis emerges that the prolonged effect of PGE4 may be due to neovascularization and not due to vasodilatation alone. This study was designed to clarify the mechanism of the prolonged effect of topical PGE4 with regard to angiogenesis. A total of 9 male hairless mice were treated with a topical application of PGE4 onitment (PGE4 powder mixed in hydrogen base) on the experimental side and only a hydrogen base on the contralateral control side of the back skin, respectively, for 7 days, once a day. Then they were divided into 3 groups. In group 1, specimens were obtained on the 7th day post-treatment using 3 mm size punch biopsy from both sides. In group 2, specimens were obtained on post-treatment 14th day. In group 3, specimens were obtained on post-treatment 28th day. The number of blood vessels were compared between the experimental side and control side with respect to neovascularization after PGE4 application using an image-analysis program under hemtoxyline-eosin stain. Treatment on the experimental side did not affect its contralateral mate, since there was no evidence of a systemic effect. From our experimental data, we could conclude that PGE4 may induce angiogenesis by topical application without systemic effect.