Experimental Studies Of ANGⅡ And VEGF On The Lymphatic Drainage In Pericardial Effusion Cases

Objective: To observe the regulating effects of angiotensin II (ANG II) and vascular endothelial growth factor (VEGF) on the frog's pericardium and lymphatic stomata so as to explore the regulating mechanism of pericardial lymph drainage in pericardial effusion cases.Methods: ANGII and VEGF was injected into the frog's peritoneum cavity. 15 days later, pericardium was taken and fixed in 2.5% glutarldehyde and 10% formaldehyde at 4℃. The results were obtained by using LM, SEM, and computerized imaging analysis to study the morphology of the stomata and their distribution density.Results: Scattered distributed pericardial stomata were found on the parietal pericardium of the frog with a few sinusoid mesothelial cells. Since there were no blood vessels in the frog's myocardium. The average diameters of the pericardial stomata in ANG II and VEGF groups were 1.79 and 1.50 microns respectively, which were much larger than those in the control group (0.72 micron, P < 0.01). The average distribution density of the stomata was 12.80/0.1 mm2 and 8.25/0.1 mm2 in ANG II and VEGF groups, which was also much higher than that in the control group (3.57/0.1 mm2, P < 0.01). Based on the computer image processing system, The sinusoid areas in ANG II and VEGF groups were 2121.79 microns2/0.1 mm2 and 2443.95microns /0.1 mm , which was larger than that in the controlgroup (995.08 microns /0.1 mm , P < 0.01). No difference was revealed between the control and BSA groups (P>0.05). Conclusions: ANG II and VEGF strongly regulate the pericardial stomata by increasing their numbers and openings with larger diameters and higher distribution density. They can also increase the sinusoid areas with the result of the higher permeability of the pericardium, which clearly indicated that ANG II and VEGF can speed up the material transfer of the pericardial cavity and playan important role in preventing myocardial interstitial edema. Pericardial lymphatic stomata were circular in shape. Summary ,VEGF could increase the number of the opened pericardial lymphatic stomata and enlarge the diameter of the lymphatic stomata with higher distribution density, through which the lymphatic stomata took part in the regulation of the pericardial lymph drainage in the cases with lymph effusion.