[Regulating effects of VEGF and ANG II on the frog's pericardial mesothelium, stomata, and angiogenesis].
OBJECTIVE
To observe the regulating effects of vascular endothelial growth factor (VEGF) and angiotensin II (ANG II) on the frog's pericardium, lymphatic stomata, and angionesis so as to understand their influences on the mesothelial permeability, lymphatic stoma regulation, and myocardial hypertrophy.


METHODS
VEGF and ANG II were injected into the frog's peritoneal cavity. The results were obtained by using LM, SEM, and computerized imaging analysis.


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, its blood supply was directly from the cardiac chambers flowing into the trabecular spaces of the myocardium. The average diameters of the pericardial stomata in VEGF and ANG II groups were 1.50 and 1.79 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 8.25/0.1 mm2 and 12.80/0.1 mm2 in VEGF and ANG II groups, which was also much higher than that in the control group (3.57/0.1 mm2, P < 0.01). The sinusoid areas in VEGF and ANG II groups were 2443.95 microns 2/0.1 mm2 and 2121.79 microns 2/0.1 mm2, which was larger than that in the control group (995.08 microns 2/0.1 mm2, P < 0.01). No angionesis were found in the frogs of the experimental groups.


CONCLUSIONS
VEGF and ANG II 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 clealy indicated that VEGF and ANG II can speed up the material transfer of the pericardial cavity and play an important role in preventing myocardial interstitial edema. Yet there is no strong evidence showing angionesis in the myocardium.
Li
J
J
Department of Lymphology, Medical School of Zhejiang University, Hangzhou 310031.
Zhou
J
J
Tota
B
B
Scalia
G
G
Gattuso
A
A
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D016228:Endothelial Growth Factors / Q000494:pharmacology*; D004848:Epithelium / Q000187:drug effects; D005260:Female; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology*; D008208:Lymphatic System / Q000187:drug effects*; D008222:Lymphokines / Q000494:pharmacology*; D008297:Male; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D010496:Pericardium / Q000187:drug effects*; D011893:Rana esculenta; D011897:Random Allocation; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D036341:Intercellular Signaling Peptides and Proteins; D008222:Lymphokines; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D000804:Angiotensin II