Role of fenestrated basement membrane in lymphatic absorption from peritoneal cavity

¹ Department of Gross Anatomy, Medical College of Georgia, Augusta, Georgia

Polystyrene spheres with a range from chylomicron size up to 30 µ were injected into the peritoneal cavity of mouse, rat and cat, and were recovered from the regional lymph nodes. The largest recovered spheres in the mouse were 16.8 µ in diameter, in the rat and cat 24 µ. Inspection of the entire population of spheres recovered from lymph nodes 48 hours after intraperitoneal injection indicated that most of the fenestrations in the subperitoneal basement membrane are less than 5 µ in the mouse, and more than 5 µ in the cat. Fenestrations in the rat are intermediate between mouse and cat. The deductions as to fenestrations from inspection of the absorbed sphere populations is fairly well in accord with the histological picture in the mouse and cat. Many spheres reach the circulation and the larger ones are filtered out in the lungs, with resulting atelectasis.