Changes in the ultrastructure of rat intestinal capillaries.

A In the control group, lanthanum particles were only distributed on capillary lumens; no La³⁺ sediment was observed on the basement membrane lateral or extravascular mesenchyme. The morphology of nuclei and organelles such as mitochondria and the Golgi complex was normal. TEM, ×8900. B In the hypoxia group, La³⁺ particles were distributed along the vessel basement membrane. Mild swelling of the organelles was observed. TEM, ×8900. C In the hypoxia group, many La³⁺ particles were found to penetrate the basement membrane through the vessel TJs into tissue space, and La³⁺ sediments were observed in the tissues of surrounding vessel. TEM, ×8900. D In the HP group, La³⁺ particles were limited to capillary lumens. No see La³⁺ sediment on the basement membrane lateral or surrounding mesenchyme. No notable abnormalities of organelles were found. TEM, ×8900. E In the HL group, La³⁺ particles were distributed diffusively in the vessel the inside of basement membrane, A large number of La³⁺ particles penetrate the basement membrane into the TJs, the surrounding vessel endothelial TJs space were enlarged. TEM, ×8900. F In the HPL group, La³⁺ particles were distributed in vessel lumens, and only in the local endothelial basement membrane. No La³⁺ particles were observed in the tissue space of surrounding vessel. TEM, ×8900.