Microvascular circulation of the cecum in horses.

The research article investigates the microvascular (small blood vessels) circulation in the cecum (a part of the large intestine) of adult horses. The scientific techniques used include microangiography, light microscopy, gross studies, and scanning electron microscopy. This study provides the understanding of how the blood supply in the cecum of horses is structured and functions.

Research Methods

• The study involved 15 adult horses,
  which were euthanized after being treated with heparin to prevent blood clotting. The cecum was then cut at the junction with the large intestine.
• The blood circulation was cleared using isotonic NaCl and the cecal lumen (inner open space) was slightly expanded.
• In 6 of the horses, a modified, radiopaque medium was injected into the vascular system to examine the details of the small blood vessels under radiographic imaging.
• The same sections that underwent radiography were also analyzed using standard histologic procedures.
• In a different group of eight horses, one of two types of plastics was injected for gross or scanning electron microscopic studies. The use of plastics contributes to a detailed analysis of the vascular structures.
• In a single horse, the lateral and medial arteries were injected with different colored plastic for gross studies to differentiate between the two blood supplies.

Findings

• The lateral and medial cecal arteries were found to supply their respective areas of the cecum and they showed minimal mixing of the two circulations.
• The major blood supply to the tip of the cecum appeared to be through the medial cecal artery.
• Both of these arteries gave rise to retia, which are complex networks of small blood vessels that enveloped the respective veins. These small vessels from the retia provided the cecal tissue and the cecal lymph nodes with blood.
• The continuation of the retia was evident through the long terminal arteries that encircled the circumference in the submucosa, forming a large submucosal plexus (network of nerves or vessels).
• This extensive plexus supplied blood to both the mucosa, and the muscular and serous coats of the cecum. Blood vessels within the layers of the muscular coat ran parallel to the muscle fibers, hence intersecting each other at right angles.

Although the abstract is truncated, these findings significantly contribute to our understanding of the circulatory system in the cecum, which may provide implications for veterinary surgical procedures and treatments for pathological conditions affecting the cecum in horses.