Question:hard
Which of the following statements about changes in articular cartilage with aging is not true?
Which of the following statements about changes in articular cartilage with aging is not true?
Show Hint
Separate aging from osteoarthritis. Surging enzymatic breakdown belongs to the disease, not to normal aging.
Updated On: Jun 24, 2026
- Total proteoglycan content is decreased
- Synthesis of proteoglycans is decreased
- Enzymatic degradation of proteoglycans is increased
- Total water content of cartilage is decreased
Show Solution
The Correct Option is C
Solution and Explanation
The trick in this question is to read aging strictly, not to mix it up with osteoarthritis.
In an old but otherwise healthy joint, the cartilage cells slow down. They make fewer proteoglycans, so synthesis is down and the matrix ends up with less total proteoglycan. Those two statements describe aging correctly.
Proteoglycans are what pull water into cartilage, because their negative charges attract it. When their amount drops, the matrix can no longer hold as much fluid, so the water content of aged cartilage falls and the tissue becomes drier and stiffer. That makes the water statement true as well. Note this is the reverse of what happens in early osteoarthritis, where the matrix swells with extra water.
That leaves the claim about a rise in enzymatic degradation. Active enzymatic chewing of proteoglycans by metalloproteinases is the signature of osteoarthritis, a true catabolic disease, not of plain aging. In aging the deficit comes from making less, not from breaking down more. So this is the statement that does not belong.
\[\boxed{\text{Enzymatic degradation of proteoglycans is increased}}\]
In an old but otherwise healthy joint, the cartilage cells slow down. They make fewer proteoglycans, so synthesis is down and the matrix ends up with less total proteoglycan. Those two statements describe aging correctly.
Proteoglycans are what pull water into cartilage, because their negative charges attract it. When their amount drops, the matrix can no longer hold as much fluid, so the water content of aged cartilage falls and the tissue becomes drier and stiffer. That makes the water statement true as well. Note this is the reverse of what happens in early osteoarthritis, where the matrix swells with extra water.
That leaves the claim about a rise in enzymatic degradation. Active enzymatic chewing of proteoglycans by metalloproteinases is the signature of osteoarthritis, a true catabolic disease, not of plain aging. In aging the deficit comes from making less, not from breaking down more. So this is the statement that does not belong.
\[\boxed{\text{Enzymatic degradation of proteoglycans is increased}}\]
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