Sika deer velvet antler protein extract modulater bone metabolism and the structure of gut microbiota in ovariectomized mice

Abstract

Osteoporosis is a systemic osteopathy characterized by bone metabolism disorders that become more serious with age increases in postmenopausal women. Recent studies have found that antler protein is the main bioactive component of cervus pantotrichum, and it has a positive regulatory effect on bone metabolism and can improve estrogen level. This study aimed to investigate the effect of velvet antler extract (VAE) on the prevention of osteoporosis and the modulation of gut microbiota in ovariectomized (OVX) mice. OVX mice treated with 12 weeks of VAE exhibited higher levels of serum BGP, Ca²⁺, CT, and HyP (p < .05). Micro-CT scans showed that VAE significantly elevated bone volume fraction (BV/TV), trabecular bone number (Tb.N), trabecular bone thickness (Tb.Th), trabecular bone connection density (Conn.D), decreased trabecular separation (Tb.Sp), and structural modality index (SMI) than untreated OVX mice. The right tibial retinaculum in the VAE group was clearer, with a clearer reticular structure, smaller gaps, a tighter distribution, and a more orderly arrangement. The gut microbiota of the cecal contents was analyzed by 16 s rDNA amplicon sequencing. The data indicated that VAE modulated the species, numbers, and diversity of the gut microbiota in OVX mice. Ovariectomy caused dysbiosis of the intestinal microbiota by increasing the ratio of Firmicutes to Bacteroidetes in mice, but the ratio decreased after treatment with VAE. These results suggest that VAE has a therapeutic effect on OVX mice via modulate bone-related biochemical markers in serum and structure of gut microbiota.

Keywords: OVX mice; gut microbiota; osteoporosis; protein extract; sika deer velvet antler.

FIGURE 1

(a–f) Serum biochemical indicators of mice. (a–f: the contents of BGP, Ca²⁺, CT, E2, FOXP3 and Hyp in serum; ^## p < .01 vs Blank control group; *p < .05 vs Model group; **p < .01 vs Model group. Con, Blank control group; Mod, Model group; VAE, velvet antler extract group; Pir, positive drug group).

FIGURE 2

(a–f) 3D reconstruction image of proximal tibia of mice. The red dotted line area represents the quantitative analysis of the histomorphometry (a and d: Con group, b and e: Mod group, c and f: VAE group).

FIGURE 3

VAE makes the number of intestinal flora OTUs in osteoporotic mice close to the control group. Con, Blank control group; Mod, Model group; Pir, positive drug group; VAE, velvet antler extract group.

FIGURE 4

(a) Shannon Diversity Index curves; (b) Shannon diversity indexes. ^## p < .01 vs Blank control group; **p < .01 vs Model group; Con, Blank control group; Mod, Model group; Pir, positive drug group; VAE, velvet antler extract group.

FIGURE 5

Beta diversity analysis diagram. Con, Blank control group; Mod, Model group; Pir, positive drug group; VAE, velvet antler extract group.

FIGURE 6

(a) Stacked bar chart of species abundance at different genera taxonomic levels. (b) Stacked bar chart of species abundance at different phyla taxonomic levels. Con, Blank control group; Mod, Model group; Pir, positive drug group; VAE, velvet antler extract group.