Adrenomedullin and Protecting Spinal Motor Neurons Against Doxorubicin-induced Toxicity

In the present study, the culture of embryonic spinal motor neurons (SMNs) was used to assess the impacts of adrenomedullin (AM) on the neurotoxic effects of doxorubicin (DOX).

To prepare the culture of rat embryonic SMNs, spinal cords were isolated from the rat embryos, digested enzymatically, and triturated to obtain spinal cell suspension. Then, the SMNs were purified from the cell suspension using a single OptiPrep gradient and cultured. The SMNs were treated with DOX (0.0-100 μM) and AM (3.125-100 nM), and their viability and apoptosis were evaluated using MTT and annexin V flow cytometric assays. Oxidative stress was assessed through the measurement of cellular reactive oxygen species (ROS), nitric oxide (NO), malondialdehyde (MDA), and 8-iso-prostaglandin F2α (iPF2α) levels. Finally, qPCR was employed to determine the expressions of interleukin1-β (IL-1β), inducible NO synthase (iNOS), tumor necrosis factor-α (TNF-α), SRY-related protein 9 (SOX9), matrix metalloproteinase (MMP)-3 and -13.

The viability of SMNs decreased following DOX treatment dose-dependently (IC₅₀=10.54 μM). DOX increased the cellular ROS, MDA, NO, and iPF2α levels (P<0.001). Additionally, AM reduced DOX-induced cell death dose-dependently (P<0.001). AM (50 nM) pretreatment also reduced the DOX-induced oxidative stress (P<0.01) and gene expression (P<0.01).

Based on the results, AM might be a protective factor against chemotherapy-induced toxicity in SMNs.