The process of resorption releases free radicals and enzymes in restricted locations to "hollow out" areas of the bone surface. Unlike bone, cartilage in these areas has little natural ability to protect itself from such free radical damage. Cartilage contains less total PUFAs than bone, with unusually low levels of n-6 PUFA. However, it apparently selectively incorporates n-3 LC-PUFA, which is considered to be a protective mechanism against oxidative stress.

Cartilage may be particularly susceptible to degradation when dietary intakes of n-6 PUFAs are high and PGE2 levels are excessive, since resorption-related free radicals increase. With these increases, cartilage cannot maintain its preferred PUFA composition. Supporting this concept is research showing that oxidative stress impairs normal bone and joint function, and that vitamin E supplementation enhances bone growth and cartilage metabolism. [1]

References

1. Watkins B, et al.
Importance of dietary fat in modulating PGE2 responses and influence of vitamin E on bone morphometry.
World Rev Nutr Dietetics 1997;82:250-9.