In a recent study, Chinese researchers evaluated the ability of a plant compound known as icariin to enhance the regenerative capabilities of bone. Icariin is a flavonoid glycoside found in medicinal herbs that belong to the genus Epimedium. The researchers developed an icariin-conditioned serum (ICS) and investigated its ability -- when combined with hyaluronic acid (HA) -- to repair a critical-sized osteochondral defect in rabbit knees.
They reported their findings in an article published in the journal BMC Complementary and Alternative Medicine.
Icariin from horny goat weed promotes bone repair with the help of hyaluronic acid
The epimedium herb, which is commonly known as horny goat weed, is widely used in Traditional Chinese Medicine (TCM). Its main active component, icariin, is a potent flavonoid that, according to studies, promotes the maturation of osteoblasts -- the bone cells responsible for bone formation. Icariin also promotes the proliferation of chondrocytes -- the cells located in cartilage -- and reduces the degradation of the extracellular matrix (ECM). The ECM is a three-dimensional network made up of proteins and other macromolecules that provides structural support to cells.
Hyaluronic acid is a type of sugar naturally produced by the body. It is known to help the skin retain water and also serves as an essential component of the ECM of cartilage. As such, HA is involved in cell proliferation, inflammation and wound repair. Research has found that gels made with HA can help slow or prevent the onset of osteoarthritis following knee injury. These gels also make great delivery vehicles for medicines that promote bone repair, especially in severe cases of cartilage injury.
For their experiment, the researchers prepared ICS using different concentrations of icariin and incubated primary chondrocytes with the sera. They measured cell proliferation rates and glycosaminoglycan (GAG) secretion to determine the influence of ICS on various cell functions. GAGs are sugar molecules (polysaccharides) that help modulate enzyme activities, regulate cell growth and control the assembly and function of the ECM.
The researchers then gave rabbits intra-articular injections of either 0.5 mL normal saline (NS), ICS, HA and a combination of ICS and HA in their right knee joints. The researchers used International Cartilage Repair Society (ICRS) scores to assess macroscopic cartilage regeneration, and histological and immunohistochemical analyses to assess cartilage repair and chondrocyte regeneration. (Related: Scientists develop a new biomaterial made from citrate to help hasten bone regeneration.)
The researchers reported that low-dose icariin (0.94 g/kg) significantly promoted chondrocyte proliferation and enhanced GAG secretion. Treatment with the combination of ICS and HA caused the femoral condyles -- the two rounded prominences at the end of the thighbone -- of rabbits to be integrated with native cartilage. ICS together with HA also caused more subchondral bone regeneration, promoted repair of cartilage defects and increased the formation of new cartilage.
Based on these findings, the researchers concluded that icariin combined with hyaluronic acid helps repair cartilage defects and can be used in bioactive material-based cartilage regeneration therapies.
Sources include:
BMCComplementMedTherapies.BiomedCentral.com
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