Vahideh Faghani zadeh - Department of Microbiology, Damghan Branch, Islamic Azad University, Damghan, Iran
Nazila Arbab Soleimani - Stem Cell Research Center, Golestan University of Medical Sciences, Gorgan, Iran
Ayyoob Khosravi - Department of Molecular Medicine, Faculty of Advanced Medical Technologies, Golestan University of Medical Sciences, Gorgan, Iran
mohammad mahdi forghanifard - Departments of Biology, Damghan Branch, Islamic Azad University, Damghan, Iran.

Background and Objectives: Oral cancer relates to oral and intestinal microbiota composition. Lactobacillus species are considered probiotic bacteria due to their ability to modulate human immune responses and therapeutic effects. This study aimed to investigate the effects of Lactobacillus plantarum (L. plantarum) on TLR۴ gene expression and its downstream pathways in a mouse model of oral cancer. Material and Methods: This experimental study was conducted in the Stem Cell Research Center, Faculty of Modern Technologies, Golestan University of Medical Sciences, Gorgan, Iran, in ۲۰۲۱. L. plantarum strain ATCC ۸۰۱۴ was used in this study. Twenty-eight male Wistar rats were divided into four groups (n = ۷). ۴-Nitroquinoline ۱-oxide (۴NQO) was used to establish oral cancer in rats. A pathological examination was adopted to confirm cancer establishment. Rats were treated with probiotic L. plantarum before and after cancer development. After extracting RNA from blood and synthesizing cDNA, the ability of lactobacilli to modulate the expression of TLR۴ genes was investigated by Real-Time PCR Methods (RT-PCR). Results: In the present study, it was observed that after causing cancer and treating the animal with L. plantarum, the expression of the TLR۴ gene decreased significantly (P-value < ۰.۰۵), which might, in turn, affect the downstream pathways, which included the decrease in the expression of BCL-۲ and NF-ĸB genes. Accordingly, the expression of the NF-ĸB gene was significantly reduced in rats received L. plantarumgavaged for two weeks after cancer induction. Conclusion: According to the obtained results, probiotic L. plantarum significantly affects the gene expression of NF-ĸB and TLR۴ in cancerous rats. It was also shown that L. plantarum was more efficient in reducing TLR-۴ and NF-ĸB genes expression when it was gavaged for ۱۴ days after tumor induction.

Lactobacillus plantarum, Probiotics, Toll-Like Receptors, Apoptosis