The study of the cytopathic effects of Blastocystis sp., ST1-3 and 6 isolated from subjects referred to medical laboratories in HT29 cell line

Background and Aim: Blastocystis sp., is one of the most common intestinal protozoan parasites found in both human and animal fecal samples. The pathogenicity and cytopathic effects of subtypes ST1-3 and 6 of Blastocystis sp., on gastrointestinal cell line are not clear. This study aimed to investigated intra-subtype variations on the apoptosis and cytopathic effects on HT-29 cell line in 2019, in Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Materials and Methods: This study was an experimental case-control investigation on Blastocystis sp., subtypes 1-3 and 6, which were isolated from stool samples of 30 symptomatic and subtypes 1-3 from 25 asymptomatic subjects. After purifying and counting the microorganisms, lysate of Blastocystis sp., was prepared from 1 × 105 of the microorganism by three freeze-thaw cycles in liquid nitrogen and a 37°C water bath. Then, the lysates of subtypes of Blastocystis were co-incubated with HT-29 cell line for 48h. Finally, the cell proliferation rate was measured using an MTT dye assay. For investigation of statistical differences on the cell proliferation based on subtypes as well as symptoms, One-way ANOVA test incorporated with GraphPad Prism was applied. Results: The results clearly indicated that all of Blastocystis sp., subtypes in comparison with non-treated control (NTC) had a cytopathic/inhibitory effect on HT-29 cells growth. The lowest cytopathic effect was seen in ST1 isolated from symptomatic patient (17.11%), while the highest was seen in ST1 isolated from symptomatic patient (25%). Indeed, ST2 showed milder cytopathic effects in HT-29 cell line in comparison with ST1, 3 and 6. However, there was not seen statistical correlation between subtypes as well symptoms and cytopathic effect. Conclusions: The findings of the current study indicated that the soluble antigen of Blastocystis subtypes 1-3 and 6, could reduce the growth of HT-29 cells, although there was no statistically significant correlation between subtypes and the cytopathic effect.