# Examining the role of trans-sodium crocetinate in alleviating colistin-induced cytotoxicity through apoptosis and autophagy pathways on HEK-293 cells

## TL;DR

This study shows that trans-sodium crocetinate can protect kidney cells from the harmful effects of colistin, a powerful antibiotic.

## Contribution

The novel contribution is demonstrating TSC's protective role against colistin-induced toxicity via apoptosis and autophagy modulation in HEK-293 cells.

## Key findings

- TSC pretreatment improved cell viability by 35% and reduced ROS by 50% in colistin-treated HEK-293 cells.
- TSC suppressed apoptosis markers (Bax/Bcl-2 ratio by 50%, cleaved caspase-3 by 55%) and autophagy proteins (LC3 and Beclin-1 by 35-45%).

## Abstract

Colistin is a crucial antibiotic for multidrug-resistant Gram-negative bacterial infections, but its nephrotoxicity limits clinical use. Trans sodium crocetinate (TSC), a synthetic crocetin derivative, exhibits anti-oxidative, antiapoptotic, and renal-protective effects. This study investigated whether TSC could alleviate colistin-induced cytotoxicity in HEK-293 cells, a human renal epithelial model.

HEK-293 cells were pretreated with varying TSC concentrations for 24 hr, followed by 200 µM colistin for another 24 hr. Cell viability was measured via MTT assay, and reactive oxygen species (ROS) levels were quantified using DCFH-DA fluorescence. Apoptotic markers (Bax, Bcl-2, caspase-3) and autophagy-related proteins (LC3, Beclin-1) were analyzed by western blotting.

Colistin reduced HEK-293 cell viability by 50%, increased ROS by 43%, and elevated autophagy markers (LC3, Beclin-1) by 50%. The Bax/Bcl-2 ratio rose by 50%, and cleaved caspase-3 increased by 33% compared to controls. However, TSC pretreatment significantly attenuated these effects: viability improved by 35%, ROS decreased by 50%, and the Bax/Bcl-2 ratio dropped by 50%. Additionally, TSC reduced Bax (40%), cleaved caspase-3 (55%), LC3 (35%), and Beclin-1 (45%) levels compared to colistin-only treatment.

These findings suggest that TSC protects HEK-293 cells from colistin-induced toxicity by reducing oxidative stress, suppressing apoptosis, and modulating autophagy. Thus, TSC may serve as a potential adjunct therapy to mitigate colistin-associated nephrotoxicity.