An in vitro analysis of the rat C6 glioma cells to elucidate the linear alkylbenzene sulfonate induced oxidative stress and consequent G2/M phase cell cycle arrest and cellular apoptosis

Abstract

Linear alkylbenzene Sulphonate (LAS) is the anionic surfactant component of globally consumed detergents. Exposure of sub-inhibitory fractions viz., 1/10th (T1), 1/5th (T2), and 1/2.5th (T3) of IC50 for 48 h, of LAS (5 μM, 10 μM, and 20 μM, respectively) to viable C6 glioma cells of rat, besides imparting morphological alterations leads to gross cytotoxicity. Expression of the damaged DNA coupled with cleaved PARP (p < 0.05; p < 0.01 and p < 0.001) were recorded for T1, T2 and T3, respectively. Subsequently, the cell cycle at G2/M check point was significantly arrested (p < 0.05 for T1 and T2; p < 0.01 for T3). The flow cytometric analysis reveals the initiation of apoptosis in C6 cells as is evident by a significant increase (p < 0.01 for T1, p < 0.001 for T2, and T3) in the intake of annexin-V, the calcium dependent apoptotic phospholipid binding protein. Moreover, significantly increased reactive oxygen species (ROS) (p < 0.05; p < 0.01 and p < 0.001) after 6 h of exposure for all the three sets, registered a declining trend (P < 0.001) when T3 cells were co-treated with N-acetyl cysteine (NAC). Furthermore, the significant attenuation (p < 0.01) of expression of the cleaved PARP and a consequent decrease (p < 0.05) in the cell cycle arrest at G2/M phase after scavenging ROS induced oxidative stress by treating C6 cells with NAC clearly evinces that LAS induced apoptosis is mediated by intracellular ROS. Thus, these findings provide a tangible basis for further investigations including in vivo studies, to unravel the molecular mechanism involved in ROS mediated and LAS induced cytotoxic manifestations.