Ethambutol (Myambutol) is an orally available anti-tuberculosis drug that may also be capable of interfering with arabinogalactan, thereby inhibiting cell wall synthesis and inhibiting bacteria, and may be used in animal modeling for hyperuricemia and optic neuropathy.

HT29 cells:25.5±4.7 µg/mL, SW620 cells:5.5±2.1 µg/mL, MCF7 cells:11.1±1.1 µg/mL, DLD1 cells:7.8±2.2 µg/mL, SW480 cells:5.8±1.3 µg/mL, HCT116 cells:5.5±1.0 µg/mL

The MTT or CCK-8 assays showed that Ethambutol (0-50µg/mL) exerted a time-dependent inhibitory effect on cell proliferation in six cell lines, including SW480 and SW620. The IC50 values for different cell lines ranged from 5.37 to 31.54µg/mL over 24-72 hours[1]. In the RGC-5 retinal ganglion cell experiment, after treating the cells with 4mM Ethambutol for 8 hours, flow cytometry and Western blot analysis confirmed a significant increase in cell apoptosis, as well as upregulation of autophagy markers such as PI3C3 and Beclin-1[2]. Additionally, treatment of Mycobacterium smegmatis with 10µg/mL Ethambutol followed by acid hydrolysis combined with HPLC and enzyme activity analysis showed changes in arabinogalactanase activity[3].

Ethambutol (250 mg/kg, administered by gavage once daily for 23 days) can induce hyperuricemia and cause pathological damage and inflammatory reactions in the thymus and spleen, manifested by thymic atrophy, fusion of the cortex and medulla, congestion of the splenic sinuses, and hemosiderin deposition [4,5]. In addition, Ethambutol (35 mg/kg/day, orally for 30 days) can induce optic neuropathy, leading to ganglion cell damage, increased retinal ganglion cell (RGC) density, and thickening of the RGC layer [6].