What would happen if human blood turned into a kind of rubbery slime that could splash into wounds and stop bleeding in record time?
Until now, it was a mystery how hemolymph, or insect blood, could clot so quickly outside the body. Researchers at Clemson University have finally figured out how this works by observing caterpillars and cockroaches. The blood of these animals changes its physical properties so that the initially bled watery hemolymph turns into a viscoelastic substance outside the body and returns to the wound, allowing it to close the wound in about a minute.
“In insects that are susceptible to dehydration, the mechanical response of blood after injury is rapid,” the researchers wrote in their paper. study Recently published in “Frontiers in Soft Matter”. “Insects can minimize blood loss by forming a primary blood clot that closes the wound and provides a scaffold for new tissue formation.”
strange exudate
The composition of hemolymph differs significantly from that of vertebrate blood. There are no red blood cells and platelets. The cells that make up the hemolymph, known as blood cells, act like white blood cells in vertebrates and perform functions such as feeding on potentially infectious bacteria and helping form blood clots over wounds. . Some insects have blood richer in blood cells than others. Even the larvae of certain species may have more blood cells in their blood than adults, and many adult butterflies and moths have hemolymph, which has fewer blood cells compared to caterpillars.
When experimenting with Sphinx moth caterpillars (manduka sexta), the researchers placed the caterpillar inside a hard plastic sleeve with holes and made an incision in one of its front legs. Greenish fluid leaked from the wound and dripped like water for several seconds. However, it quickly turned into a viscoelastic fluid and dripped more slowly. The last drop did not flake off, but instead retreated toward the wound.
This all happened within 60-90 seconds. Similar results were found in cockroaches (Periplaneta Americana) When the tip of one antenna is cut off.
In both types of insects, blood clots began to form after the hemolymph regressed. This clot scab became so hard for cockroaches that even a tungsten needle could not penetrate it.
it’s in the blood
To investigate the structure of hemolymph clots, scientists took some of the sticky (but not fully clotted) material from caterpillar or cockroach wounds and examined it using a phase-contrast microscope. Ta. Phase contrast enhances the contrast, allowing you to see details (such as cells) in transparent specimens such as hemolymph. The partially clotted hemolymph was made up of those described in the following literature: study This is a “polymer filament embedded with blood cells,” and blood clots from old wounds are more viscous and thicker than those from new wounds.
Some specimens contained fragments of eschar from scabs that had begun to form over healed wounds. These were freeze-dried to avoid any residual moisture and deformation, and were then further observed using X-ray, micro-CT, and SEM images. The results showed that the outer parts of the Earth’s crust, which are most exposed to air, are covered with more layers. Crowded. The scab material also contained large aggregates of blood cells that assembled into chain structures to form blood clots.
How quickly do blood cells begin to collect? When the researchers returned to the scene, they observed viscous but unhardened hemolymph oozing from the wound.
The bleeding stopped after about a minute, but about three minutes after the last drop formed, the blood cells started forming a scab, which contains a polymer strong enough to thicken and hold it together. It turned into a viscoelastic fluid and then retreated. Some blood cells form pseudopodia (much like amoebas do) and then attach to other blood cells. The resulting agglomeration further increased the viscosity of the liquid and eventually formed a scab.
Insect hemolymph is not the only body fluid that exhibits viscoelastic properties. Even saliva is watery when it first leaves the mouth, but it thickens over time as it leaves the body, such as when it extends from the end of a dog’s tongue. Human blood is not viscoelastic. However, this research may have implications for human medicine in the future. Clemson researchers believe future advances could give them some of the bug’s benefits when it comes to wound healing.
“We hope that our findings will spark interest among biochemists and molecular biologists,” they said. Said“Designing a fast-acting thickening agent for vertebrate blood, including human blood.”
Soft matter frontier, 2024. DOI: 10.3389/frsfm.2024.1341129
