BERBERINE ENRICHING AKKERMANSIA MUCINIPHILA ALLEVIATE OVARIECTOMY-INDUCED GLUCOSE AND LIPID METABOLISM DISORDERS AND OSTEOPOROSIS IN RAT

Background and Aims:
Abnormal glucose and lipid metabolism and osteoporosis are typical symptoms of postmenopausal women. Multiple studies have shown berberine (BBR), a kind of natural alkaloid, as a microbiota regulator, can significantly improve metabolic diseases such as type 2 diabetes, obesity, and insulin resistance. Whether berberine could also alleviate ovariectomy (OVX)-induced metabolic disorders and osteoporosis deserve further study.
Methods:
Experimental anxiety was established in specific pathogen-free (SPF) or germ-free (GF) rats. The SPF rats were divided as Sham, OVX, OVX+BBR (Fig. 1A). The GF rats were divided as GF-Sham, GF-OVX, GF-OVX+BBR (Fig. 1F), OVX, OVX+AKK and OVX+ pasteurized AKK (pAKK) (Fig. 2E). OVX+BBR and GF-OVX+BBR group were treated with BBR for 4 weeks, OVX+AKK and OVX+pAKK group were gavaged with 10⁹ CFU / ml AKK or pAKK for 4 weeks. Blood glucose, ALT, ALP, TC and TG were detected by BS-350E fully automatic biochemical analyzer. Bone mineral density was detected by X-ray apparatus with a small-animal high-resolution collimator. Trabecular bone was scanned by micro-CT. Fecal gut microbiota was detected by 16s rRNA. Metagenomic sequencing was used to detected Akkermansia muciniphila (AKK) gene expression.
Results:
In SPF rats, BBR could significantly inhibited OVX-induced body weight gain at 4^th week of BBR treatment (Fig. 1B). And so did the blood glucose, ALT, ALP and TG (Fig. 1C). Bone mineral content and density were reduced in OVX group, and BBR could rescue it (Fig. 1D). Micro-CT scan shown OVX-induced osteoporosis could be alleviated by BBR (Fig 1E). In GF rats, BBR did not inhibited OVX-induced body weight gain (Fig. 1G). And, so did the blood glucose, ALP and TC (Fig. 1H). Fecal 16s rRNA results shown Lactobacillus, Akkermansia and unclassified_p_Firmicutes were decreased in OVX group, which were increased in OVX+BBR group (Fig 2A). Meanwhile, functional analysis of 16s rRNA shown genes related to carbon metabolism and carbon fixation pathway were significantly enriched in OVX group, and the pathways that were significantly reduced by BBR were: carbon fixation pathway, insulin resistance, fatty acid metabolism pathway, and adipocytokine signaling pathway (Fig 2B). Metagenomic sequencing results shown AKK expresses a variety of enzymes related to carbon metabolism (Fig. 2C). Furthermore, a variety of metabolism-related pathways were enriched in AKK, such as carbon metabolism, amino sugar and nucleotide sugar metabolism, starch and sucrose metabolism and glycolysis / gluconeogenesis (Fig. 2D). Furthermore, after gavage AKK or pAKK to OVX GF rats, OVX-induced weight gain is suppressed by AKK but not by pAKK (Fig. 2F).
Conclusion:
Berberine may attenuate OVX-induced glucose and lipid metabolism disorders and osteoporosis by enriching Akkermansia muciniphila, and the underlying mechanism deserves further study.