Photo courtesy  of: and scottchan

Knee Joint InflammationIt’s common when you twist your ankle or strain a muscle to reach for some aspirin or any non-steroidal anti-inflammatory to make it better. Some people use aspirin to help take care of their every day aches and pains, too. We in the U.S. consume 15 tons of aspirin a day and 19 billion tablets a year. Aspirin does have side effects and they can be quite serious. Let’s break down just what the heck is going on in your body when you have an injury and how aspirin helps make it better.

Ligament, cartilage, tendon, disc, skin, and muscle can all tear. When there is a tear to any of these structures, the cells that are injured send out a distress call to the body. They do this by using a chemical called arachidonic acid. Arachidonic acids are released by cells when there is an injury to the body. This acid sends off a cascade of enzymes to be created that promote inflammation and swelling.  It’s the body’s natural defense system to injury and it helps bring in other cells that that try to fix the problem.

Let’s move on with the injured tissue before going back to what aspirin does during the process (see paragraph 5 to skip to the answer). The arachidonic acids send out their message and more chemicals come in response to promote inflammation and swelling. In conjunction, cells come in to clean up all of the dead debris in the area. You may know them as white blood cells, but there are specific cells that we will talk about. The ones to focus on are called neutrophils and macrophages. You can think of them as Pac-Man that eat up everything dead. In addition to these cells, another one helps to block blood from rushing into the area. This cell is called fibrin and it helps create a clot with the platelets carried by your blood. Think about this as the operating room for a surgery. The area must be completely sterile and access to the room is restricted to health professionals only. This is exactly what your body is doing. too. Next, the surgeons must enter to repair the wounded site.

These surgeons of the body are fibroblasts. They use collagen to help repair an injured area. Imagine that collagen is the thread during surgery. Collagen is the major component of tendons, ligament, skin and is also in cartilage, bones, and the discs of your spine. Collagen is also in muscle, but it is not the majority component. When the new fibroblasts at the site lay down collagen, they lay it down haphazardly. This is called type III collagen. The body basically says “We have to repair the injury! Lay down whatever we can!” As the healing process continues, a different collagen is laid down called type 1 collagen. This is the final product that most collagen turns out to be when your body heals. In fact, type I collagen is 90% of the collagen in our entire body. These are just the highlights of a very complex process, but it gives you a gist of the events taking place. So back to the initial question, where does aspirin come into this process?

Remember the arachidonic acids? That was the chemical released by injured cells. Aspirin and NSAIDs help to stop the cascade of inflammation by stopping the arachidonic acid from spreading around to promote inflammation. It’s not the arachidonic acid that causes the swelling, it’s the other chemicals that are switched on because of the acid in the area that causes it to happen. So your swelling goes down since there is less arachidonic acid in the area when aspirin is used, and the big ball of different cells that usually respond the injured tissue is much smaller.

If you’re curious like me, you might be thinking “that all sounds great, but are there any repercussions for changing the inflammatory process? Isn’t it important?” The answer is that there are repercussions and you should definitely be aware of them. Stay tuned for next week’s blog discussing NSAID’s further and answering some of these lingering questions……..