Effects of Pregnancy on Progression of Osteoarthritis Induced by Monosodium Iodoacetate in Rats

Hormones, particularly estrogen, are known to play a role in the development of osteoarthritis (OA). In relation to this, the impact of pregnancy on OA remains unknown. Pregnancy leads to decreased expressions of both synthetic and degradation genes of articular chondrocytes, as determined using in vitro tests, but no in vivo studies have been performed exploring pregnancy and OA simultaneously. The present study investigates the effect of pregnancy on the progression of OA in the rat joint degeneration model using an intra-articular injection of monosodium iodoacetate (MIA). Twenty Wistar rats were divided into four groups: A-Pregnancy and intra-articular injection of MIA; B-MIA injection in naive rats; C-Pregnancy, and D-Sham injection of saline in naive rats. Articular cartilage was evaluated 18 days after the detection of vaginal plug in female rats using Janusz's macroscopic score, equilibrium partitioning of an ionic contrast agent via microcomputed tomography, and glycosaminoglycan (GAG) quantification. Results show that there was no significant difference in GAG content, attenuation, volume, and thickness of articular cartilage between pregnant and non-pregnant groups. Contrary to our initial hypothesis, pregnancy does not have observable effects on MIA-induced OA in rats at 3 weeks.