Mechanical stress (shaking) and reticuloendothelial function in the chick embryo

Abstract

Stage 34 (8 day) and 41 (15 day) chick embryos were exposed (3 min) to two separate amounts of mechanical (shaking) stress. Eggs were shaken in the horizontal plane through their long axes. A laboratory shaker (Eberbach) was used to produce the stress and one complete excursion defined as carriage movement through 7.92 cm (3.96 cm in opposite directions). Reticuloendothelial system (RES) activity, as measured by colloidal carbon clearance (CCC), was evaluated following administration via an allantoic vein. Shaking stage 34 or 41 embryos at 100 excursions per minute (EPM) did not affect CCC; shaking them at 300 EPM resulted in an immediate and significant depression of CCC. Stage 41 embryos exposed to 300 EPM and reincubated for either 1, 2 or 4 hours prior to CCC determination reverted to control CCC values sooner than stage 34 embryos subjected to the same regimen. Functional RES response to mechanically induced stress has now been shown for the first time in an embryonic system (at two distinct developmental stages). The response appears to parallel that reported for various adult organisms. Furthermore, we suggest a temporal relationship regarding functional development of the embryonic RES.