Natural Eggshell Membrane Attenuates Chondrocyte Inflammation and Surgically Induced Osteoarthritis in Rats

Abstract

Osteoarthritis (OA) is a degenerative joint disease that mainly occurs due to the cellular inflammatory response and the destruction of joint cartilage. Natural eggshell membrane (NEM), a byproduct of egg processing, might be a promising knee OA treatment because of its anti-inflammatory properties and resemblance to synovial membrane components. Therefore, we aimed to study the anti-inflammatory effects of NEM in OA, utilizing both in vitro experiments with primary chondrocytes and in vivo studies with a surgical rat model of knee OA. In vitro studies showed that NEM treatment improved cell viability in chondrocytes exposed to interleukin-1α by upregulating chondrogenic genes and inhibiting enzymes that degrade the extracellular matrix (ECM). Furthermore, the anti-inflammatory effects of NEM were observed in chondrocytes induced by lipopolysaccharide. Administering NEM orally for 56 days after OA surgery resulted in enhanced joint swelling reduction and improved mobility in animal models, as well as an increase in bone density and cartilage compressive strength in a concentration-dependent manner. It inhibited inflammatory markers (5-lipoxygenase and prostaglandin E2) and extracellular matrix (ECM)-degrading enzymes (MMP-2 and MMP-9) in both the cartilage and synovium. Simultaneously, there was an upregulation in the expression of chondrogenic genes (Sox9, aggrecan, and Col-2). The histopathological and immunohistochemical analyses demonstrated that NEM’s anti-inflammatory, anti-apoptotic, and chondrogenic properties contributed to the mitigation of joint degradation and synovial inflammation. Therefore, NEM is a potential alternative or functional food agent that addresses both anti-inflammatory and chondroprotective aspects in OA.