Ischemia/reperfusion injury in porcine intestine - Viability assessment

Table 4 Summary of main findings from transmission electron microscopy of porcine jejunum at selected intervals of mesenteric occlusive ischemia and reperfusion

Ischemia (h)	Observations	Ischemia/reperfusion (h/h)	Observations
0	Intact musculature. Some variation in the electron density in the muscle cells, focal swollen mitochondria’s with vacuolized matrixes1
1	Intact musculature. Discrete intercellular edema. Lymphocytes in the interstitial space. Increased variation in the electron density in the muscle cells. Some cells have increased electron density (darker). Some of the mitochondria are more prominent. Some minimal fat vacuoles are visible2	1-3	Inflammation, cell death, sparse fine-vacuolization of the sarcoplasm, slightly swollen mitochondria2
2	More prominent variation in electron density between muscle cells. Increased number of vacuoles, some of them are fat vacuoles. Focal edema, thickening of the mitochondrial cristae. Some lysosomes with membrane fragments2	2-3	Inflammation, cell death, more comprehensive fine-vacuolization of the sarcoplasm, slightly swollen mitochondria2
3	Same results as at 2 h, but a few more interstitial immune response cells are visible. Monocytes, macrophages, and a few granulocytes. Vacuoles in the sarcoplasm. Slightly swollen mitochondria2	3-3	Inflammation, cell death, more comprehensive fine-vacuolization of the sarcoplasm, slightly swollen mitochondria, focal single cell necrosis, swollen cell nuclei2
4	Same changes as at 3 h, but the changes are more prominent as the cells with higher electron density are more condensed, and there are more vacuoles around the mitochondria2	4-3	Pronounced cell shrinking/cell death, swollen cell nuclei, loss of cohesion, interstitial edema3
5	Focal edema, variations in electron density, thickening of the mitochondrial cristae, vacuoles in the sarcoplasm, swollen mitochondria, interstitial lymphocytes/monocytes/granulocytes, loss of plasma-membrane and coherence, focal single cell necrosis3	5-3	Increased cell shrinking/cell death, swollen cell nuclei, loss of cohesion, interstitial edema3
6	Necrosis, focal large vacuoles in some mitochondria3	6-3	Increased cell shrinking/cell death, swollen cell nuclei, loss of cohesion, interstitial edema3
7	Necrosis with macrophages. Non-necrotic cells appear like the cells at time intervals 3-6 h3
8	Like the results at 7 h3

Changes in the muscularis propria and serosa are described (3 pigs, a total of 58 samples). The results are indexed by a superscript number by the end of each sentence.

¹Normal/light changes,

²Visible cell damage, but still probably viable,

³Probably irreversible cell damage.