Evaluation of phyto-medicinal efficacy of thymoquinone against Arsenic induced mitochondrial dysfunction and cytotoxicity in SH-SY5Y cells

Background: It is evaluated that a few million individuals worldwide are experiencing Arsenic (As) harmfulness coming about because of anthropogenic discharges. There is likewise proof to propose that As can affect the peripheral, as well as, the central nervous system (CNS). On the contrary, thymoquinone (TQ), a biologically active ingredient of Nigella sativa has exhibited numerous neuro-pharmacological traits since ancient times. Hypothesis/Purpose: In the present study, the neuroprotective efficacy of TQ was explored by primarily studying its antioxidant and anti-apoptotic potential against Arsenic trioxide (As2O3) induced toxicity in SH-SY5Y human neuroblastoma cell lines. Study design: For experimentation, cells were seeded in 96 well tissue culture plates and kept undisturbed for 24 h to attain proper adhesion. After 75-80% confluence, cells were pretreated with 10 mu M and 20 mu M thymoquinone (TQ) for 1 h After adding 2 mu M As, cells were set aside for incubation for 24 h without changing the medium. Methods: The mitigatory effects of TQ with particular reference to cell viability and cytotoxicity, the generation of reactive oxygen species, DNA damage, and mitochondrial dynamics were studied. Results: Pretreatment of SH-SY5Y cells with TQ (10 and 20 mu M) for an hour and subsequent exposure to 2 mu M As2O3 protected the SH-SY5Y cells against the neuro-damaging effects of the latter. Also, the SH-SY5Y cells were better preserved with increased viability, repaired DNA, less free radical generation and balanced transmembrane potential than those exposed to As2O3 alone. TQ pretreatment also inhibited As2O3-induced exacerbation in protein levels of BAX and PARP-1 and restored the loss of Bcl(2) levels. Conclusion: The findings of this study suggest that TQ may prevent neurotoxicity and As2O3-induced apoptosis and cytotoxicity. It is, therefore, worth studying further for its potential to reduce the risks of arsenic-related neurological implications.