Low-Level Laser Mitigates Cisplatin-Induced Oxidative Stress and Apoptosis via AMPK-Mediated Autophagy in PC12 Cells

Platinum-based chemotherapeutic agents, such as cisplatin, form the cornerstone of many modern anticancer treatment regimens. Despite their clinical effectiveness, long-term use is often limited by dose-related side effects, notably peripheral neuropathy, which significantly impacts patient quality of life and restricts treatment success. Neuroprotective strategies are still limited. Low-level laser (LLL) therapy, also known as photobiomodulation, has recently gained recognition as a noninvasive approach capable of reducing various tissue damages, including nerve injuries. However, the cellular and molecular mechanisms behind its protective effects in chemotherapy-induced neurotoxicity are not yet fully understood. In this study, we examined the neuroprotective effects of LLL in an in vitro model of cisplatin toxicity using PC12 neuronal cells. PC12 neuronal cells were pretreated with LLL irradiation at 660 nm and 5 J/cm² for 10 min prior to exposure to 10 μM cisplatin for 24 h. Cell viability and cytotoxicity were assessed using MTT and LDH assays. Apoptosis was evaluated via TUNEL staining and caspase-3 activity. Mitochondrial function and oxidative stress were examined by JC-1 staining for membrane potential, MitoSOX for mitochondrial ROS, and MDA assay for lipid peroxidation. AMPK expression was silenced using siRNA, and protein levels related to autophagy, apoptosis, and AMPK signaling were analyzed by Western blotting. Our results showed that pretreatment with LLL at 5 J/cm² significantly improved cell viability and decreased cisplatin-induced cytotoxicity and apoptosis at a concentration of 10 μM. LLL reduced oxidative stress caused by cisplatin and maintained mitochondrial function, as demonstrated by lower lipid peroxidation, decreased mitochondrial ROS production, and stabilization of mitochondrial membrane potential. In addition, we found that these protective effects were mediated through activation of the AMPK signaling pathway, which enhanced autophagy and inhibited apoptotic processes. Silencing of AMPK eliminated the neuroprotective effects of LLL, confirming its key role in this mechanism. Overall, our findings suggest that LLL therapy exhibits robust neuroprotective effects against cisplatin-induced neuronal damage through AMPK-driven autophagy, offering a promising adjunctive strategy for managing chemotherapy-induced peripheral neuropathy.