Paws for Thought

Oh, dem’ achy bones

“Winter is coming.” Some of you may immediately think of knights, White Walkers and dragons as in ‘Game of Thrones.’ For the majority of us, however, those three words conjure thoughts of stiff legs, stilted gaits, and the season’s fashion of Stanfields’ long johns. Achy joints are not just limited to we bipeds but also to our furred family quadrupeds. In this two-part article, part one will focus on the anatomy of a joint (I can hear some groaning) and part two will discuss the treatments and products to manage joint pain (less groaning).

A pet doesn’t have to be a senior citizen to require joint care supplements, pain medication or physical therapy. Degenerative arthritis can result from an injury or can be the result of genetics/joint conformation.

If your pet is stiff, has poor range of motion in a joint, difficulties jumping up on the bed or into litter boxes, then you will need some education about joint care options and an understanding of what is happening in your pet’s

Joints. The joints we are concerned with when we talk about degenerative arthritis are synovial joints. They consist of two bones and a fibrous capsule holding the two bones together. The two bones surfaces are covered with slippery cartilage that must be able to glide across each other with minimal friction no matter what the patient’s activity level is, and they must continue to be able to glide easily in this way repeatedly throughout the patient’s life.

Prevention of the progression of arthritis is all about maintaining the normal

structures of the joint. In many cases, this involves providing the biochemical components of these structures as nutritional supplements.

Joint structure No 1: The cartilage.

Articular cartilage surfaces of the joint are the caps on the ends of the bone. These are the smooth surfaces that must glide across each other. Cartilage is made up of cartilage cells called chondrocytes suspended in a cartilage matrix (think of fruit suspended in Jell-O). The matrix, which represents 95 percent of the cartilage, consists of collagen and proteoglycans. Collagen is the tough support protein that act as the steel girders of the body, holding everything from bone to skin in the shape it is meant to hold.

Proteoglycan is not a word familiar to the general public but since most joint nutritional supplements relate to it, it is important to know what it is. Proteoglycans are the materials surrounding the collagen fibers. They consist of a long core protein molecules with glycosaminoglycans, or GAGs, growing off their sides like bristles on a hair brush. These hair brush bristles consist of keratin sulphate (which is made in the body from a biochemical called glucosamine) and chondroitin sulphate, both of which are included in many popular over-the-counter joint supplements. The core proteins carrying their bristles connect to a central GAG called hyaluronan, which is also used in joint support products. These GAG bristles allow the proteoglycan molecule to soak up water like a little sponge. It is this sponge

characteristic that allows the cartilage to be soft like a mattress, yet slippery when the two bones of the joint move across each other.

Chondrocytes are the cells that actually secrete the cartilage matrix. While the cells represent only a small portion of the cartilage (five percent), they must remain healthy so as to produce new matrix when the old matrix is damaged.

Joint structure No. 2 : The Joint Capsule or Synovial Membrane

This is the capsule that encloses the joint. The capsule has an outer tough, fibrous layer and an inner layer that secretes joint fluid, a fluid that provides both nutrition and lubrication to the enclosed joint. The joint capsule must keep unwanted proteins and biochemicals out of the joint and only let the desired nutrients inside. After all, the joint must be kept smooth and the lubricants pure if they are to maintain the joint throughout the patient’s entire lifetime. The joint capsule has two types of cells: Type A Synoviocytes and Type B Synoviocytes. The Type A cells are all about removing impurities and cleaning up debris. Type B cells produce Hyaluronan (mentioned above), an important lubricant in the joint.

When there is an injury or simply poor conformation, the cartilage becomes roughened and can chip, flake off, or even wear down. The joint capsule becomes inflamed and thickened and no longer functions normally.

In providing treatment, our goal is to alleviate the pain and inflammation and provide the biochemical building blocks that allow the joint to heal itself.

This will be discussed next time in part 2.