A new method of measure of bubble gas volume shows that interleukin-6 injected into rats has no effect on gas embolism

Bondi M, Cavaggioni A, Gasperetti A, Rubini A. A new method of measure of bubble gas volume shows that interleukin-6 injected into rats has no effect on gas embolism. Undersea Hyperb Med 2009 1 36 (2):1031 115. The pleiotropic cytokine interleukin-6 increases in the plasma of rats after an air dive. Interleukin-6 shares both of inflammatory and anti-inflammatory properties and may condition the vascular system and gas embolism after an air dive. Up to now it is not known whether interleukin-6 has an effect on gas embolism. Aim of this work is to study the effect of interleukin-6 on gas embolism after a standard decompression protocol in a rat model. The volume of gas bubbles was measured in the heart cavities with a new method based on the buoyancy of the heart at different pressures which is physically sound, accurate and precise down to 10(-4) cm(3). No effect was found after injecting physiological doses of interleukin-6 at different times before the air dive. The mortality of the rats in the first half hour after the decompression was associated with a substantial gas volume measured in the heart. Multi-variate logistic regression analysis showed that the female rats had a higher risk compared to male rats of developing a substantial bubble volume and of not surviving; the spring-summer season was a risk factor for the survival. Further studies are needed to see whether interleukin-6 in association with other cytokines has ail effect on gas embolism.