Critical role of insulin‑like growth factor binding protein‑5 in methamphetamine‑induced apoptosis in cardiomyocytes.

Methamphetamine (MA) is a highly abused amphetamine‑like psychostimulant. At present, the mechanisms underlying MA‑induced cardiotoxicity are poorly understood. The cardiotoxic effects have yet not been clearly elucidated with respect to the apoptotic pathway. Insulin‑like growth factor binding protein‑5 (IGFBP5) is important for cell growth control and the induction of apoptosis. The aim of the present study was to analyze whether IGFBP5 is involved in MA‑induced apoptosis as a novel target. MA‑induced apoptosis was observed in neonatal rat ventricular myocytes (NRVMs) in a concentration‑dependent manner using a terminal deoxyribonucleotide transferase‑mediated dUTP nick end‑labeling assay. Using reverse transcription polymerase chain reaction and western blotting, MA was demonstrated to induce concentration‑dependent increases in the expression of IGFBP5. Silencing IGFBP5 with small interfering RNA significantly reduced apoptosis and suppressed the expression of caspase‑3 in NRVMs following treatment with MA. To the best of our knowledge, the present study provided the first evidence suggesting that IGFBP5 is a potential therapeutic target in MA‑induced apoptosis in vitro, providing a foundation for future in vivo studies.