Amikacin Cytotoxicity on Equine Joint Cells

A recent study was published titled, “Amikacin induces rapid dose-dependent apoptotic cell death in equine chondrocytes and synovial cells in vitro.” The study was authored by Pezzanite, L.; Chow, L.; Soontararak, S.; Phillips, J.; Goodrich, L.; Dow, S.

This in vitro study aimed to evaluate the cytotoxic effects of amikacin on equine chondrocytes, synoviocytes, and bone marrow and adipose-derived mesenchymal stem cells (MSC).

Chondrocytes, synovial cells, and adipose and bone marrow derived MSC were harvested post-mortem from three horses with no evidence of osteoarthritis. The effects of amikacin on cell viability were assessed for different exposure times, concentrations, and with pH buffered or unbuffered in media, as well as in the presence of synovial fluid. Cell metabolism/viability was assessed by colorimetric MTT assay, and cell proliferation was assessed by live cell imaging. Cell viability was assessed using trypan blue and dimeric cyanine nucleic acid stain. Mechanism of cell death was also evaluated.

Amikacin exhibited a dose-dependent killing of chondrocytes, synovial cells, and bone marrow and adipose-derived mesenchymal stem cells. At a concentration of amikacin achieved following typical intra-articular medication (25 mg/mL), rapid cytotoxic effects were seen for all cell types. The primary mechanism of cell death was via apoptosis, and cytotoxicity was not mitigated by the addition of synovial fluid in vitro.

Bottom line: Amikacin at clinically applied doses induces rapid, pronounced cell death of equine joint cells, so amikacin doses currently used intra‐articularly should be reconsidered.