Importance of interstitial matrix hydration in intestinal chylomicron transport.

We have shown previously that lymph flow has a profound effect on intestinal chylomicron transport. However, since lymph flow both determines the rate of convective movement of chylomicrons within the interstitium and reflects the degree of hydration of the interstitial matrix, we were unable to determine which factor was more important for the inverse relation between the chylomicron appearance time and lymph flow. In this investigation, we measured the chylomicron appearance time in rats with a normal lymph flow and expanded matrix (study A), in rats with a reduced lymph flow but expanded matrix (study B), and finally in rats with a dehydrated matrix (study C). The chylomicron appearance times were 11.7, 13.6, and 21.7 min for the rats from studies A-C, respectively. Thus, the data obtained from this study indicate that the matrix hydration may exert a more significant influence on chylomicron movement than lymph flow per se. In conclusion, the reduced chylomicron appearance time produced by expansion of the mucosal interstitium results from a diminished resistance of the interstitial matrix to chylomicron movement rather than a decreased transit time due to an enhanced convective flux of chylomicrons.