Thymoquinone prevents cisplatin neurotoxicity in primary DRG neurons

Chemotherapy-induced peripheral neuropathy (CIPN) is a substantial, dose-limiting adverse effect that occurs in cancer patients. Cis-dichlorodiamine (II) platinum (CDDP, cisplatin) is a platinum-based chemotherapeutic agent that causes severe acute and chronic peripheral neuropathies in 30% of cancer patients. Thymoquinone (TQ), a leading bioactive constituent of Nigella sativa seeds, has been reported to have antioxidant, anti-inflammatory, anti-neoplastic and neuroprotective properties. Dorsal root ganglia (DRG) include different classes of primary sensory neurons, such as nociceptors, mechanoreceptors, and proprioceptive neurons. Here, we investigated the neuroprotective activity of TQ against cisplatin neurotoxicity in cultured DRG neurons. We prepared neuronal cultures from DRGs of adult mice, pre-treated them with or without varying doses of TQ prior to exposure of cells to cisplatin. The preparations were viewed under the scope before and after the treatment at 24 h, 48 h, and 72 h time points. We analyzed neuronal cell viability and neurite outgrowths, and evaluated morphologic changes of neuronal or non-neuronal cells. TQ significantly increases the ability to extend neurites and neuronal cell viability when compared to the culture conditions which were treated with cisplatin only. Although we provide compelling evidence for the protective activity of TQ against chemotherapy-induced neurotoxicity, further detailed investigations in preclinical settings are warranted for its clinical use.