Hellio Le Graverand M P, Reno C, Hart D A
McCaig Center for Joint Injury and Arthritis Research, Faculty of Medicine, University of Calgary, Alberta, Canada.
Osteoarthritis Cartilage. 1998 Sep;6(5):341-50. doi: 10.1053/joca.1998.0133.
Articular cartilage is known to be influenced by estrogen and the pregnancy-associated hormone, relaxin, in vitro. Such observations have raised the possibility that articular cartilage in females may be subjected to unique regulatory influences by such hormones in vivo. The purpose of this study was to evaluate mRNA levels for several relevant molecules in the articular cartilage of pregnant and non-pregnant rabbits.
Total RNA was extracted from New Zealand White rabbit knee articular cartilage using the TRIspin method. The total RNA was reverse transcribed and analysed by the sensitive molecular technique of semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) using rabbit specific primer sets.
Total RNA yield from articular cartilage from primigravida rabbits was reduced to 65% of age-matched control values (P = 0.0003); however the yield from multiparous animals was not significantly depressed. In both cases, DNA yields were not affected by pregnancy. There was a general tendency for depressed mRNA levels for most genes investigated in cartilage from pregnant animals. Articular cartilage from multiparous rabbits showed a significant decrease in mRNA levels for relevant molecules such as type II collagen, biglycan, collagenase and tissue inhibitors of metalloproteinases (TIMP)-1, as well as necrosis factor-alpha (TNF-alpha), inducible nitric oxide synthase (iNOS) and cyclo-oxygenase 2 (COX-2). Transcripts for collagenase and lumican were significantly lower in cartilage from primigravida rabbits. Transforming growth factor beta 1 (TGF-beta 1) transcript levels were significantly decreased in both pregnant groups. In contrast, basic fibroblast growth factor (bFGF) and insulin-like growth factor-2 (IGF-2) mRNA levels were significantly decreased in cartilage from primigravida rabbits, whereas transcripts for these molecules were upregulated in the cartilage of multiparous rabbits.
The present study demonstrates that regulation of RNA levels in articular cartilage during pregnancy is complex and is influenced by the parity and/or the skeletal maturity of the animals.
已知体外情况下，雌激素和妊娠相关激素松弛素会对关节软骨产生影响。这些观察结果增加了一种可能性，即女性体内的关节软骨可能会受到这些激素在体内的独特调节作用。本研究的目的是评估怀孕和未怀孕兔子关节软骨中几种相关分子的mRNA水平。
采用TRIspin方法从新西兰白兔膝关节软骨中提取总RNA。使用兔特异性引物对，通过半定量逆转录-聚合酶链反应（RT-PCR）这一灵敏的分子技术对总RNA进行逆转录和分析。
初产兔关节软骨的总RNA产量降至年龄匹配对照组值的65%（P = 0.0003）；然而，经产动物的产量并未显著降低。在这两种情况下，DNA产量均不受妊娠影响。怀孕动物软骨中所研究的大多数基因的mRNA水平总体上有降低的趋势。经产兔的关节软骨中，相关分子如II型胶原蛋白、双糖链蛋白聚糖、胶原酶和金属蛋白酶组织抑制剂（TIMP）-1，以及肿瘤坏死因子-α（TNF-α）、诱导型一氧化氮合酶（iNOS）和环氧化酶2（COX-2）的mRNA水平显著降低。初产兔软骨中胶原酶和亮氨酸聚糖的转录本显著较低。在两个怀孕组中，转化生长因子β1（TGF-β1）转录水平均显著降低。相比之下，初产兔软骨中碱性成纤维细胞生长因子（bFGF）和胰岛素样生长因子-2（IGF-2）的mRNA水平显著降低，而在经产兔软骨中这些分子的转录本上调。
本研究表明，怀孕期间关节软骨中RNA水平的调节是复杂的，并且受动物的胎次和/或骨骼成熟度影响。
