Changes of microvascular architecture, ultrastructure and permeability of rat jejunal villi at different ages

Table 1 Comparison of the microvascular architecture of villi at different ages (mean ± SEM)

	Ablactation rats	Adult rats	Aged rats
Diameter of arteriole (µm)	6.17 ± 1.51	10.47 ± 2.25a	16.73 ± 3.28c
Diameter of venule (µm)	20.43 ± 3.17	25.45 ± 3.07b	25.50 ± 3.34
Ratio: arteriole/venule	0.30 ± 0.04	0.41 ± 0.04a	0.65 ± 0.06c

^aP < 0.01,

^bP < 0.05 vs ablactation rats;

^cP < 0.01 vs adult rats.

Table 2 Comparison of the endothelial ultrastructure of villi at different ages (mean ± SEM)

	Newborn	Ablactation	Adult	Aged rats
Endothelial holes (number/µm)		3.01 ± 0.38	3.51 ± 0.35b	5.19 ± 0.48d
Plasmalemmal vesicles (number/0.1 µm2)	17.7 ± 4.25	39.1 ± 10.36a	75.3 ± 12.13c	38.0 ± 11.14d
Basal membrane (nm)		25.2 ± 5.26	43.5 ± 5.86c	60.5 ± 6.89d
Vascular permeability (µg/g)		28.1 ± 4.64	64.4 ± 9.34c	116.4 ± 15.63d

^aP < 0.01 vs newborn rats;

^bP < 0.05,

^cP < 0.01 vs ablactation rats;

^dP < 0.01 vs adult rats.