Experimental Studies on Connective Tissue of the Capsular Ligament:Influences of Aging and Sex Hormones

Abstract

Influences of aging and sex hormones on connective tissue metabolism in the hip joint capsule of Wistar rats were analyzed both biochemically and morphologically. As age advanced, collagen content and collagen fihril diameter of the hip joint capsule tended to increase gradually in both sexes until sexual maturation was reached. Collagen content was significantly greater in males than in females after sexual maturation. The collagen content and fibril diameter were considerably increased by ovariectomy and significantly decreased by the administration of estrogen, o r estrogen combined with progesterone, whereas they were significantly increased by the administration of testosterone in orchiectomized male rats. K e { j uiords: hip joint capsule; aging; sex hormones; colagen content; collagen fibril diameter Accepted 12.vii. 76The most prominent clinical sign of congenital dislocation of the hip in the perinatal period is relaxation of the hip joint capsule. It has been suggested by Andr6n & Borglin (1961 a, b) that female sex hormones participate in the relaxation.The aim of the present experiment is to study the influences of sex hormones on collagen metabolism in the joint capsule by analyzing the collagen content and collagen fibrif diameter. This analysis is an approach to clarifying the causative factors of the relaxation. MATERIALS AND M E T H O D S Treatment of animalsFifty-two Wistar rats, 26 females and 26 males, 3-36 weeks of age, were subjected to an analysis of the influences of aging and 180 Wistar rats, 105 females and 75 males, were subjected to an analysis of the influences of sex hormones.The rats were kept in individual cages and fed on Nihon CLEA Rat Chow and given water ad libitum. They underwent ovariectomy, orchiectomy or sham operation at 3 weeks of age with o r without subsequent hormone treatment.The hormones administered to each animal group were estradiol benzoate (20 pg, per rat), progesterone (10 mg, per rat) and testosterone propionate (2.5 rng, per rat) dissoIved in 0.1 ml of sesame oil. Control groups received sesame oil only. The injections were given twice a week subcutaneously.At 10 weeks of age, the animals were first stunned with a blow and then killed by cervical dislocation. The joint capsules of the hip and knee were dissected free of fatty tissue; the right capsules were prepared for electron microscopic examination and the left ones were hydrolyzed and assayed for hydroxyproline. ACTA ORTHOP. 47, 5 474HIROMICHI HAMA Er AL. Measurement of collagen fibril diameterAfter dissection, the specimens were fixed in 1 per cent osmium tetroxide solution in 0.2 M veronal acetate buffer, pH 7.4, dehydrated through a graded series of ethanol and embedded in Epon 812. Ultrathin sections were cut with glass-knives on an ultramicrotome (Porter-Blum MT-2). The sections were stained with uranyl acetate and examined under the electron microscope (Hitachi HS-7D type) with an accelerated voltage of 50 KV and a direct magnification of 30,000.Four areas in every section were selected at random ...

Effect of estrogen on tendon collagen synthesis, tendon structural characteristics, and biomechanical properties in postmenopausal women

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Effect of administration of oral contraceptives in vivo on collagen synthesis in tendon and muscle connective tissue in young women

“…The naturally secreted progesterone has been shown to have both inhibiting (18) and stimulating effects (67) on collagen synthesis. However, the difference in endogenous progesterone between control and OC was physiologically negligible.…”

Absolute serum hormone levels predict the magnitude of change in anterior knee laxity across the menstrual cycle

“…This would appear to be consistent with basic science studies that have demonstrated an interactive effect between estradiol and progesterone in modifying collagen structure. 24,27 Romani and colleagues 29 also found stronger correlations between ACL stiffness and estradiol concentrations once the effects of other hormones were accounted for.…”

“…This attenuation was thought to either be due to a saturation of the estrogen receptors, or perhaps a downregulation of the receptor response with prolonged exposure. 22 While the literature supports the presence of estrogen and progesterone receptors in the human anterior cruciate ligament (ACL) 23 and that sex hormones may have a direct influence on collagen tissue, [24][25][26][27][28] the results by Yu and colleagues suggest the degree of pulsatility of these hormones can modify the response by the receptors and influence collagen structure and metabolism.…”

“…While Hamlet and colleagues 30 identified androgen receptors on the human ACL in young adult males, they did not observe the presence of these receptors in females. Further, the effects of testosterone on collagen tissue have consistently been found to be anabolic in nature, increasing collagen content and fiber diameter 24,27 and decreasing elastin content. 31 This would suggest testosterone would have more of a stiffening effect on the capsuloligamentous structures, rather than contributing to increased knee laxity as we observed.…”