ABSTRACT
Objective To observe the effects of fecal microbiota transplantation on intestinal microbiota and brain function in sepsis rats. Methods Sixty male Sprague Dawley (SD) rats were divided into sham operation group, model group and fecal microbiota transplantation (FMT) group by random number table, each group 20 rats. The rat model of sepsis was established by injection of lipopolysaccharide (LPS) 10 mg/kg in tail vein. FMT group received nasogastric infusion of feces from healthy donor. Fecal samples were collected on the 6th day after the modeling to detect the levels of intestinal microbiota composition; the brain function was also evaluated by electroencephalogram (EEG), and the proportion of each waveform in EEG was calculated. After sacrifice of rats in different groups, the brain tissues were taken, the levels of protein expression and positive cells of Iba-1 in brain tissue were detected by Western Blot and immunohistochemistry method. Results ① Intestinal flora analysis showed that: the diversity index and Chaol index of the intestinal microbiota in model group were significantly lower than that in sham operation group (observed species:282±40 vs. 473±37, Chao1 index: 730±21 vs. 837±27, both P < 0.05); compared with the model group, the diversity index and Chaol index in FMT group were obviously higher (observed species: 461±20 vs. 282±40, Chao1 index:840±16 vs. 730±21, both P < 0.05). At phylum, family, genus level analysis showed that the proportion of Firmicutes phylum and Fusobacterium were obviously lower than those of sham operation group [Firmicutes phylum (22.12±1.34)% vs. (78.01±1.23)%, Fusobacterium: (2.03±0.17)% vs. (5.03±0.19)%, both P < 0.05], and the proportions of Proteobacteria, Bacteroidetes phyla and Acidaminococcaceae, Fusobacteriaceae, Enterbacteriacecae, Alistipes were markedly higher in model group [Proteobacteria: (70.21±2.35)% vs. (19.45±2.17)%, Bacteroidetes phyla: (4.12±0.19)% vs. (2.50±0.64)%, Acidaminococcaceae: (12.51±0.87)% vs. (1.01±0.12)%, Fusobacteriaceae: (13.62±1.27)% vs. (2.31±0.19)%, Enterbacteriacecae: (18.24±2.13)% vs. (4.15±1.51)%, Alistipes: (4.53±0.27)% vs. (1.47±0.33)%, all P < 0.05]; compared with the model group, the proportion of Firmicutes phylum and Faecalibacterium in FMT group were significantly higher [Firmicutes phylum: (72.14±2.31)% vs. (22.12±1.34)%, Faecalibacterium: (5.01±0.27)% vs. (2.03±0.17)%, both P < 0.05], and Proteobacteria, Bacteroidetes phyla and Acidaminococcaceae, Fusobacteriaceae, Enterbacteriacecae in FMT group were obviously lower [Proteobacteria: (14.23±1.98)% vs. (70.21±2.35)%, Bacteroidetes phyla: (3.15±0.18)% vs. (4.12±0.19)%, Acidaminococcaceae: (0.91±0.11)% vs. (12.51±0.87)%, Fusobacteriaceae: (1.25±0.15)% vs. (13.62±1.27)%, Enterbacteriacecae: (3.50±0.21)% vs. (18.24±2.13)%, all P < 0.05]. ② EEG analysis showed that the percentages of δ wave in EEG in model group was significantly higher after modeling than that in sham operation group [(16.86±0.50)% vs. (10.67±0.65)%, P < 0.05]; the ratios of δ wave in EEG was significantly lower in FMT group than that in the model group [(12.87±0.60)% vs. (17.35±0.41)%, P <0.05]. The incidence of abnormal EEG in sham operation group was 0, the incidence of abnormal EEG in model group was significantly increased [the ratios of δpredominant wave, θpredominant wave, low-voltage were 66.7% (6/9), 66.7% (6/9), 77.8% (7/9) respectively], the ratios of above abnormal waves in EEG in FMT group were obviously lower than those in model group [the ratios of above abnormal waves in FMT group were respectively 9.1% (1/11), 9.1% (1/11), 18.2%(2/11)]. ③ Western Blot analysis showed that the protein expression of Iba-1 in cortex in model group obviously was higher than that in sham operation group (Iba-1/β-actin: 1.39±0.16 vs. 0.67±0.18, P < 0.05); the expression of Iba-1 in cortex tissue of FMT group was markedly lower than that in model group (Iba-1/β-actin: 0.51±0.14 vs. 1.39±0.16, P < 0.05). ④ Immunohistochemistry of Iba-1 in cortex analysis showed that there were no Iba-1 positive cells in the cortex in sham operation group; Iba-1 positive cells were found in the cortex in model group; the number of Iba-1 positive cells in FMT group was less than that in model group. Conclusion FMT can improve the construction of intestinal microbiota, and ameliorate the brain dysfunction in SAE.