Attenuation of Oxidative Stress-Induced Cell Apoptosis in Schwann RSC96 Cells by <i>Ocimum Gratissimum</i> Aqueous Extract

Abstract

<b><i>Objectives:</i></b> Cell transplantation therapy of Schwann cells (SCs) is a promising therapeutic strategy after spinal cord injury. However, challenges such as oxidative stress hinder satisfactory cell viability and intervention for enhancing SCs survival is critical throughout the transplantation procedures. <i>Ocimum gratissimum,</i> widely used as a folk medicine in many countries, has therapeutic and anti-oxidative properties and may protect SCs survival. <b><i>Methods:</i></b> We examined the protective effects of aqueous <i>O. gratissimum</i> extract (OGE) against cell damage caused by H₂O₂-induced oxidative stress in RSC96 Schwann cells. <b><i>Results:</i></b> Our results showed that the RSC96 cells, damaged by H₂O₂ oxidative stress, decreased their viability up to 32% after treatment with different concentrations of up to 300 μM H₂O₂, but OGE pretreatment (150 or 200 μg/mL) increased cell viability by approximately 62% or 66%, respectively. Cell cycle analysis indicated a high (43%) sub-G1 cell population in the H₂O₂-treated RSC96 cells compared with untreated cells (1%); whereas OGE pretreatment (150 and 200 μg/mL) of RSC96 cells significantly reduced the sub-G1 cells (7% and 8%, respectively). Furthermore, Western blot analysis revealed that OGE pretreatment inhibited H₂O₂-induced apoptotic protein caspase-3 activation and PARP cleavage, as well as it reversed Bax up-regulation and Bcl-2 down-regulation. The amelioration of OGE of cell stress and stress-induced apoptosis was proved by the HSP70 and HSP72 decrease. <b><i>Conclusion:</i></b> Our data suggest that OGE may minimize the cytotoxic effects of H₂O₂-induced SCs apoptosis by modulating the apoptotic pathway and could potentially supplement cell transplantation therapy.