Objective To establish a rat model of intestinal dysbacteriosis and provide methodological support for the study of intestinal dysbacteriosis after cerebral ischemia.
Methods Totally 19 male specific pathogen free (SPF) Sprague-Dawley (SD) rats were divided into a normal group (n = 5), a donor group (n = 9) and a recipient group (n = 5). The rats of donor group were subsequently assigned into 3 groups and middle cerebral artery occlusion (MCAO) was performed in the rats on the first, second and third day after a 3-day adaptive feeding and cecal flora were taken as grafts 72 hours after the MCAO operation. After gavage administration of streptomycin sulfate for exhausting intestinal microbes, the rats of the recipient group were administered with the grafts by gavage once a day continually for three days. The cecal specimens of all the rats of the three groups were examined with gram staining microscopy. The contents of ileum, cecum and transverse colon of normal and recipient rats and cecum contents of donor rats were sampled for 16S rDNA high-throughput sequencing and the microbial structure and characteristics of the contents were detected and analyzed with bioinformatics.
Results Compared with that of the ileum, the species diversity of cecum and transverse colon flora in normal rats increased significantly (P < 0.01) and the flora in the three intestinal segments were mainly composed of thick-walled bacteria. Compared with that of the normal rats, the species diversity of cecal flora in the donor rats decreased significantly; the species composition analysis at phylum level showed that the Firmicutes decreased significantly and the Proteobacteria increased significantly (both P < 0.01). Compared with that of the normal rats, the species diversity of cecum and transverse colon flora in the recipient rats decreased significantly (P < 0.01). The cecal flora of the recipient rats was similar to that of the transverse colon, mainly composed of Bacteroides. There were no significant differences in α diversity ACE index and β diversity among the ileum, cecum and transverse colon flora of the recipient rats and the cecum flora of the donor rats (P > 0.05 for all), but the flora structure of the rats of the two groups were similar.
Conclusion Gavage administration of cecal flora 72 hours after MCAO operation could be used to establish a rat model of intestinal flora imbalance similar to the structure and characteristics of microorganisms of the rats with ischemic stroke.
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