Pomegranate extract can inhibit key cellular pathways and activities involved in the progression of osteoarthritis.
The researchers derived human chondrocytes, cells found in the cartilages, from osteoarthritis-affected cartilage using enzymatic digestion methods. These chondrocytes were treated with a standardized pomegranate extract and then stimulated with Interleukin-1β, a protein involved in cellular responses to injury. To understand the pathways influenced by the extract, gene expression of different types of p38-Mitogen Activated Protein Kinase (MAPK) was measured by Reverse Transcription Polymerase Chain Reaction, while their activation was studied through immunoblotting and immunoprecipitation. The DNA binding activity of a transcription factor, known as Runt-related Transcription Factor 2, was analyzed using sensitive and specific Enzyme-Linked Immunosorbent Assay methods.
The outcomes showed that Interleukin-1β enhances the phosphorylation of two types of p38-MAPK in these cells. The cells also expressed three isoforms of p38-MAPK and activating p38-MAPK preferentially occurred through the activation of a protein, known as MKK3. Furthermore, the pomegranate extract inhibited the Interleukin-1β-induced activation of MKK3, one isoform of p38-MAPK, and reduced the DNA binding activity of Runt-related Transcription Factor 2.
