Effects Of Fe₃O₄ Nanoparticle On Gut Microbiota, SCFA And Serum Biochemical Markers In Rats

Objective: The purpose of this research was to discuss the effects of SD rats exposure to ferroferric oxide Nano particles（Nano-Fe₃O₄） on physiological and biochemical, the short chain fatty acid in intestinal, intestinal flora’s change, and discussed that the change of intestinal microbial community structure and flora metabolism disorder effects on the body.Methods: The SD rats were orally administered with Nano-Fe₃O₄（0, 185, 740mg/kg） for 28 days, weighing once every week, getting fresh feces samples by the method of forced. The rats were sacrificed at 28 th day, get serum, weighing the organ of liver, kidney, spleen, heart, lung, brain, oophoron, testis, and calculate organic indexes. The liver and colon were made pathological section, observe the pathological change. The concentration of AST, ALT, MDA, SOD, GSH, NO, BUN, Cr and UA were detected by enzyme linked immunosorbent assay. The content of acetic acid, propanoic acid and butyric acid in faeces were detected by gas chromatography. The difference of structure of intestinal flora was analysis by polymerase chain reaction-denaturing gradient gel electrophoresis. The change of the intestinal microflora were calculated quantitatively by high throughput sequencing.Results: The effect of rats exposure to Nano-Fe₃O₄ on body weight wasn’t significant difference from the first week to the 4th week in all groups（P>0.05）. Compared with the control, the organ coefficient of spleen, lung, liver, heart and ovary of female rats were not significant difference in low and high doses（P>0.05）. The organ coefficient of kidney was increased and the organ coefficient of brain in high dose group was decreased significantly（P<0.05）, but the organ coefficient of kidney and brain in low dose group were not significant difference（P>0.05）. Compared with the control, the organ coefficient of heart, spleen, liver, kidney, lung, brain and testis of male rats were not significant difference in all groups（P>0.05）.Compared with the control, the pathological sections showed that there were large amount of inflame cells in the liver tissue, liver sinuses obvious dilation, interlobular boundaries were obscure, collect abbacy vein and intrahepatic blood sinus mild expansion, dissociation of hepatic cord, the boundary between the cell membrane is not clear, part of the liver cells were smaller, nucleolus site color became weak or broken, hepatic macrophage increased in male and female rats in low and high doses groups. The epithelial cell were appeared vacuolar degeneration, goblet cells arranged loosely, the number of columnar absorbing cells decreased, cytoplasm dye lightly, nuclear shape irregularly.At 28 day, compared with the control, the concentration of the AST, ALT, BUN, Cr, UA, MDA, GSH and NO in serum were not significant difference of male and female rats in all groups（P>0.05）; but the concentration of SOD of male and female rats in high dose group was decreased significantly（P<0.05）, the concentration of the SOD in serum was not significant difference of male and female rats in low group（P>0.05）.Compared with the control, the concentration of acetic acid in faeces of male rats was decreased significantly（P<0.05） in low and high dose groups in the 4th weeks, but the concentration of propionic acid in faeces of female rats was increased significantly（P<0.05） in low and high dose groups. The concentration of butyric acid in faeces of female rats was increased significantly（P<0.05） in high dose group, otherwise the concentration of butyric acid in faeces of male rats was decreased significantly（P<0.05） in high dose group.Fecal bacteria 16 s r RNA genes by PCR amplification then use high-throughput sequencing, compared with the control, the Simpson and Shannon of high dose group of female rats was significant difference（P<0.05）, also the Ace and Chao1 of high dose group of male rats was significant difference（P<0.05）.The firmicutes were 65.23% and 30.44% for control and high dose group of female rats respectively, and the bacteroidetes were 27.32% and 37.21% respectively. In male rats group, the firmicutes were 61.58% and 49.05% respectively, and the bacteroidetes were 34.48% and 32.62% respectively.Females in the control group and high dose group of bacteroides classes, respectively, 27.27%, 37.23%, clostridium classes, respectively, 57.62%, 19.98%, phylum gamma deformation were 8.9%, 23.3%, bacteroides classes, clostridium highest richness in each group. Male rats in control group and high dose group of bacteroides classes, respectively, 34.07%, 32.53%, clostridium classes, respectively, 39.78%, 38.20%.Female control group and high dose group of responding to Mr Wolfowitz bacteria respectively 10.52%, 23.56%, MAO spirillum were 23%, 10.52%, rumen bacteria branch, respectively, 17.33%, 8.99%. Males females in the control group and high dose group of responding to Mr Wolfowitz bacteria, respectively, 23.63%, 24.90%, MAO spirillum were 16.79%, 12.37%, rumen bacteria branch, respectively, 19.44%, 17.55%. Adult SD rats ferroferric oxide（Nano-Fe₃O₄） nanoparticles exposure may affect the structural changes of the intestinal microflora and bacteria metabolic disorders, and then change the intestinal short chain fatty acids composition proportion, a certain influence on physiological and biochemical metabolism in rats, the damage in the body have a certain role.