Histone deacetylase inhibitor, Trichostatin A mitigates ionizing radiation induced redox imbalance by regulating NRF2/GPX4/PINK1/PARKIN signaling in mice intestine.

Background: Gastrointestinal-acute radiation syndrome (GI-ARS) caused by moderate to high doses of ionizing radiation exposure contribute to early death in humans. GI injury is also a common adverse effect seen in cancer patients undergoing abdominal/pelvic radiotherapy. Currently, no countermeasure agents have been approved for medical management of GI-ARS. The present study aims to evaluate the mechanism of action of Trichostatin A(TSA), a pan histone deacetylase inhibitor, against radiation-induced GI injury.

Methods: TSA (150 ng/kg bw) was administered to mice 1 h and 24 h after 15 Gy abdominal irradiation. Expression of various markers of oxidative stress, mitochondrial dysfunction, and apoptosis were checked in the jejunum, and their possible regulation through the Nrf2 signaling pathway was evaluated.

Results: TSA administered post-irradiation (15 Gy + TSA) elevated intestinal total antioxidant and glutathione levels by regulating the expression of Slc7A11 and antioxidant proteins, GCLC, GPX4, and TXNRD1. Improved mitochondrial membrane potential, ATP levels, downregulation of mitochondrial quality control proteins, (PINK1 and PARKIN), and differential regulation of the apoptotic proteins, (BAX, PUMA and BCL2) with reduced intestinal epithelial cell apoptosis in the TSA-adminstered group were observed. TSA also upregulated Nrf2 in the presence of its specific inhibitor, ML385, suggesting its involvement in regulating Nrf2 signaling during oxidative stress induced by radiation in intestine. H & E stained jejunum cross-sections revealed that TSA mitigated radiation-mediated intestinal injury in mice.

Conclusions: Present findings indicate that TSA is beneficial in mitigating the damaging effects of ionizing radiation in the intestine.