Osteoarthritis is a progressive joint condition identified by ongoing deterioration of the cartilage matrix, and there is currently no effective drug treatment plan. Metformin-modified exosomes isolated from bone marrow-derived mesenchymal stem cells can become a new method for treating osteoarthritis due to their avoidance of oral drug adverse reactions and immunogenicity.

To study the controlling impact of exosomes from metformin-altered bone marrow-derived mesenchymal stem cells on chondrocytes.

Rabbit bone marrow-derived mesenchymal stem cells and chondrocytes were cultured in vitro. Bone marrow-derived mesenchymal stem cells derived exosomes and metformin pretreated bone marrow-derived mesenchymal stem cells derived exosomes were collected using a high-speed centrifuge. Chondrocytes were cultured with exosome-containing culture medium for 24 hours and then treated with 100 µmol/L H₂O₂ for 24 hours. The capability changes of two extracellular vesicles on chondrocyte proliferation and migration were detected using CCK8 assay and scratch healing experiment, respectively. Western blot analysis and RT-qPCR were employed to examine the alterations in the expression of type II collagen, P16 protein, and their mRNA in chondrocytes.

Western blot analysis was utilized to assess the changes in the expression of MKK7/JNK pathway proteins. ELISA kits were utilized to measure the activity of cell superoxide dismutase and the levels of malondialdehyde in chondrocytes.

(1) In an oxidative stress environment, the proliferation and migration abilities of chondrocytes were weakened. The two types of exosomes could restore the proliferation and migration abilities of chondrocytes to a certain extent. Metformin pretreated bone marrow-derived mesenchymal stem cells derived exosomes had a significantly better improvement effect (P < 0.05). (2) Compared with normal bone marrow mesenchymal stem cell-derived exosomes, metformin pretreated bone marrow-derived mesenchymal stem cells derived exosomes could more effectively increase type II collagen expression and superoxide dismutase activity (P < 0.05), and were also more effective in reducing P16 expression and malondialdehyde levels (P < 0.05). (3) The two types of exosomes could inhibit the expression of MKK7 and p-JNK proteins to a certain extent, and the inhibitory effect of metformin pretreated bone marrow-derived mesenchymal stem cells derived exosomes was more significant (P < 0.05). The results show that in an oxidative stress environment, metformin pretreated bone marrow-derived mesenchymal stem cells derived exosomes resist chondrocyte aging and promote chondrocyte proliferation by inhibiting the MKK7/JNK pathway.