Analysis of changes in intestinal microbiota in female Wistar rats at the stage of breast cancer induction by N-methyl-N-nitrosourea

Abstract

The intestinal microbiota, having enormous metabolic potential, makes a significant contribution to the physiological and pathological processes of humans and animals and is currently considered as an important factor in the pathogenesis of cancer. The aim of this study is to determine changes in the quantitative and qualitative composition of the intestinal microbiota in Wistar rats during chemical induction of breast cancer (BC). Material and methods. The work was performed on female Wistar rats (n = 40) aged 3 months, weighing 200–210 g, using cultural methods for studying fecal microbiota in intact rats (1 group) on the 1st, 14th, 35th days and in rats with induction of breast cancer and and in rats, whereby N-methyl-N-nitrosourea was administered to induce breast cancer (2 group) on the 1st (before injection of N-methyl-N-nitrosourea), 14th, 35th days after injection of N-methyl-N-nitrosourea. Results and discussion. In all experimental animals, representatives characteristic of the intestinal normobiota of warm-blooded animals predominated, namely: Bifidobacterium spp., Lactobacillus spp., Escherichia coli with pronounced enzymatic properties, Enterococcus spp., Clostridium spp. In addition, Staphylococcus spp., yeast-like fungi of the genus Candida and mold. Escherichia coli with reduced enzymatic activity was also detected. It was established that the isolated bacteria belonged to 3 types, 4 classes, 5 orders, 6 families, 6 genera of the bacterial domain. Also, 2 genera of fungi belonging to the order Saccharomycetales were isolated. The most significant changes in the composition of the intestinal microbiota were noted in rats with chemically induced breast cancer on the 35th day tumor induction: the appearance of pathogenic microflora in the intestine was revealed.

Keywords

• female wistar rats
• intestinal microbiota
• induction
• n-methyl-n-nitrosourea
• dysbiosis
• breast cancer
• carcinogenesis