COMPLEX ALTERATIONS IN GENE-EXPRESSION OCCUR IN THE KNEE LIGAMENTS OFTHE SKELETALLY MATURE MULTIPAROUS RABBIT DURING PREGNANCY

Pregnancy is known to influence the function of ligaments of the knee in both humans and rabbits. During pregnancy, ligament laxity increase s. The mechanism by which these changes in ligament function occur is unknown. The present study was undertaken to assess changes in the pat tern of gene expression for a number of molecules which could be invol ved in the alterations in tissue function. Using RNA isolated from pre gnant and age-matched nonpregnant rabbits, levels of mRNA for matrix m olecules, proteinases and inhibitors, cytokines and growth factors and inducible nitric oxide synthase were assessed by semi-quantitative RT -PCR. The results indicate that the pregnancy-induced changes in the p attern of gene expression is very complex and differences in the chang es observed for the medial collateral ligament and the anterior crucia te ligament may also indicate that ligament-specific effects of pregna ncy occur, mRNA levels of some molecules were significantly elevated o r suppressed, while others were unchanged, indicating that the changes observed were specific rather than general. While the extent of the m olecules assessed was designed to be representative rather than exhaus tive, the results indicate that there is likely no simple cause and ef fect relationship between the observed mechanical alterations during p regnancy and alterations in gene expression in the affected ligaments. (C) 1998 Elsevier Science B.V.