Effect of interleukin 12 (IL-12) on embryonic development and yolk sac vascularisation.

Background: In the recent days there has been an increase in diseases known as "angiogenic diseases" characterized by pathologic vascularisation. In the rat, the development of embryonic vessel starts to occur at 9.5 days of gestation. In mammals, the vascular system starts developing in a very early embryonic stage. The majority of rat embryo circulation system gets complete approximately at 11 - 12 days. Therefore the in vitro study of 9.5 - 11.5-day old embryo culture could be a suitable model to study the effects of angiogenic and antiangiogenic substances on yolk sac vascularisation. In the present study, the effects of Interleukin-12 (IL-12) on the yolk sac vascularisation are investigated during the in vitro embryo culture, where the latter angiogenic factor was added to serum.

Methods: After 48-hour culture period, effects of different doses of IL-12 (50 ng/ml, 100 ng/ml, and 200 ng/ml) were estimated morphologically.

Results: According to morphologic scoring system, the total morphologic score, yolk sac diameter, crown rump length, and somite number were retarded in all experimental groups when compared to control. These developmental retardations were statically significant. There was also a poor development in the yolk sac vascularisation and the heart.

Conclusion: As a result, the IL-12 could cause developmental retardation of embryos owing to its antiangiogenic effect (Tab. 3, Fig. 2, Ref. 39).