Visible healing is obvious. Lets say your pet suffers a skin puncture or tear in a demarcation dispute. Over the next two weeks the skin visibly repairs itself. You can watch the damage disappear. All of us are familiar with the inflammation that occurs around a cut, the formation of a scab and the growth of new skin under the scab to fill the defect. The real repair, however is less visible.
What White Blood Cells Do
At all times, white blood cells circulate in the blood stream waiting for accidents to happen. When an injury occurs, such as a skin puncture wound, the infantry arrive. Cells called neutrophils, the body's most populous white blood cells, converge where the defensive barrier of the skin has been breached. They kill germs that have got through. This creates debris but almost immediately, other white blood cells called macrophages, quite literally 'big eaters', arrive, engulf and digest the debris. At the same time new cell formation begins at the margins of the wound. These new cells grow across the wound, under the protection of the carapace-like blood clot that has formed. Like buds on a tree in spring, new blood vessels sprout from the closest intact vessels and grow with the new cells as they repair the defect.
Chemicals Control Repair
All of these activities are controlled by chemical regulators called cytokines, proteins so small and so scarce they are almost impossible to detect. Cytokines either stimulate or inhibit cell growth. There is a natural, well-regulated balance between these opposing cytokines. Healing - a return to homeostasis - depends upon cytokines coordinating their activity. If you consider that the entire lining of your pet's digestive system is virtually renewed several times each week, that gives you an idea of how coordinated these activities are. This natural balance of cytokine activity is influenced by hormones produced by the pituitary, thyroid and adrenal glands, even by the nervous system, by your pet's 'state of mind'.
Cell Walls Are Vital
The wall of a cell is to the cell what the skin is to the body, its first and most important line of defence. It protects the contents of the cell and is the part of the cell most at risk. The cell wall is not a permanent structure. It is a membrane made up of proteins embedded in a fatty substance. A pet's diet influences the levels of different fatty acids in cell membranes. Some nutritionists argue that good levels of omega 3 fatty acids in cell walls make those cells less likely to be affected by inflammation than those with a preponderance of omega 6 fatty acids.
Cell Wall Repair
Cell walls are covered with special receptor sites that are specifically designed to recognise and bind certain nutrients, hormones and other substances to the cell. These biochemicals enter the cell through these receptor sites and influence the cell's activity. (Technically, biochemicals binding to receptor sites trigger signalling pathways within a cell.) To ensure that the receptor sites are always kept in pristine condition bits of the cell wall with their receptor sites are constantly being withdrawn into the cell where they are examined, repaired if necessary, and then returned to the cell's surface. Inside the cell, scavengers called lysosomes recognise and eliminate defective sections of the cell wall. Healing and repair takes place unseen at the cellular level.
New Cells Are Produced
For as long as a cell lives it must remain in good working order but its life span is often short and it must be replaced. Cats and dogs have trillions of cells in their bodies and millions are replaced every single day. Cells make new cells by passing on their genetic information, their DNA, from one generation to the next. Technically, DNA also transcribes information into another related molecule called RNA that can travel out of a cell nucleus. RNA translates the information it acquired from DNA and directs cells to manufacture specific proteins that determine the form and function of all aspects of life. These processes of replication, transcription and translation of information are the most basic processes of life and are profoundly balanced or "homeostatic".
The Role Of Enzymes
Overseeing DNA activity is an intricate selection of proteins called enzymes. Enzymes are the mechanics that carry out DNA's instructions. They cut up DNA molecules, dissect out bits, add other bits and put it all back together with amazing precision and speed. But lots can go wrong. A DNA molecule might be injured by, lets say, radiation or ultra-violet light, or inhaled cigarette smoke or any of hundreds of other chemicals. When this happens, it makes a mistake when it copies itself. The new cell is 'wrong'. If it is not detected it multiplies 'wrong' and becomes a cancer. But molecular troops are present waiting for mistakes to happen. When DNA copying goes wrong or a spontaneous mutation occurs special enzymes move in, snip out the damaged bit of DNA, fill the gap with a correct version, then paste the whole system back together. Molecular mistakes occur daily and each one is a potential cancer. Virtually all are caught in time. Your pet's body evolved to heal itself right down to the molecular level. Our medical care works with and when possible enhances these brilliant defences.