OBJECTIVETo study the difference of histologic examination and type II collagen expression in the rib cartilage of patients at different age.

METHODSThe patients were divided into three groups, as children group (5 to 10 years old), teenager group (11 to 17 years old), and adult group (18 to 29 years old). Histologic examination of rib cartilage and quantitative analysis of type II collagen with immunohistochemical stain were carried out in the three groups. Motic Med 6.0 A system was used to quantitate immunohistochemical image through measurement of mean photodensity. The results were statistically analyzed.

RESULTSAmong the three groups, the children's rib cartilage had the most blood vessels, the most chondrocytes, well-distributed stain of matrixes, and the type II collagen was expressed actively and highest in photodensity. The rib cartilage of teenager group had less blood vessels, unhomogeny distributed stain of matrixes, the enlarged and separated cartilage lacunae. The rib cartilage in adult group showed the least blood vessels, the least chondrocytes, the hyalinization of perichondrium, the most deposition of calcium salt, and the type II collagen was expressed at the lowest level in photodensity. Statistical analysis showed significant differences among the three groups (P < 0.01).

CONCLUSIONSHistologic structure in human rib cartilage changes during the aging process and the type II collagen is decreased with the increase of age.