Full-Fat Rice Bran (FFRB) Ameliorates Insulin Resistance and Modulates Muscle Parameters in HFD-Fed Ovariectomized Mice: Potential Gut-Muscle Axis Involvement
In ovariectomized mice fed a high-fat diet, supplementation with 10–20% full-fat rice bran reduced HOMA-IR, attenuated muscle atrophy gene expression, and altered gut microbiota composition compared to unsupplemented HFD controls.
| Endpunkt | Grad | Richtung | Effekt | Studien |
|---|---|---|---|---|
| Insulin resistance (HOMA-IR) | D | ▲ Günstig | Redução numérica em OHR10 e OHR20 vs OH; IC 95% não reportado | 1 |
| Glucose tolerance (IPGTT AUC) | D | ▲ Günstig | Redução numérica em grupos OHR vs OH; IC 95% não reportado | 1 |
| Muscle atrogin-1 and MuRF-1 gene expression | D | ▲ Günstig | Downregulation em OHR vs OH por RT-qPCR (2−ΔΔCT); magnitude exata e IC 95% não reportados | 1 |
| Grip strength | D | — Unzureichend | Mudança desde baseline (Δ semana 11 − semana 0) relatada; direção e magnitude não discriminadas no texto disponível | 1 |
| Gut microbiota composition | D | ▲ Günstig | Aumento de táxons produtores de SCFAs em OHR vs OH; métricas de diversidade e IC 95% não disponíveis no texto fornecido | 1 |
| Fecal SCFAs (acetate, propionate, butyrate) | D | ▲ Günstig | Aumento numérico em grupos OHR; valores absolutos e IC 95% não reportados no texto disponível | 1 |
| Plasma lipid parameters (TG, TC) | D | — Unzureichend | Tendências de melhora com significância estatística variável entre doses; IC 95% não reportado | 1 |
Kontext
Postmenopause-related estrogen decline promotes insulin resistance, chronic low-grade inflammation, and accelerated muscle atrophy. A high-fat diet worsens these effects through gut dysbiosis and reduced SCFA production. Identifying dietary interventions capable of modulating the gut-muscle axis in this context has clinical relevance.
Was die Studie zeigte
OHR10 and OHR20 reduced HOMA-IR relative to OH, with OHR20 showing the greatest reduction; exact 95% CIs and effect sizes were not fully reported in the available text. Atrogin-1 and MuRF-1 expression in gastrocnemius was reduced in OHR groups versus OH, indicating reduced ubiquitin-proteasome pathway activation. Gut microbiota composition shifted toward SCFA-producing taxa in supplemented groups. Lipid parameters (TG, TC) showed improvement trends, but statistical significance varied across doses.
Wie es durchgeführt wurde
Controlled preclinical trial, 12 weeks, in female ICR mice (n=6 YC; n=5 per OVX group, total ≈36). Bilateral ovariectomy was performed prior to the experiment to simulate postmenopause. High-fat diet (45% kcal fat) induced insulin resistance. Analyses included IPGTT, HOMA-IR, RT-qPCR of gastrocnemius and colon, 16S rRNA gut microbiota sequencing, fecal SCFA quantification, and plasma biochemistry.
Effektgröße
Effect sizes with 95% CIs were not explicitly calculated; comparisons relied on p<0.05 threshold. Translational clinical magnitude is indeterminate from murine data.
Einschränkungen
Exclusively animal (murine) model with n=5 per OVX group; insufficient sample size for robust inference; no reported power calculation. RoB 2 and ROBINS-I do not apply to preclinical animal studies, but lack of evaluator blinding and small n represent relevant biases. The FFRB dose has no validated human equivalent. The young sham group is not an appropriate comparator for efficacy inferences.
In der klinischen Praxis
These data do not support clinical recommendation of rice bran for postmenopausal women with sarcopenia or insulin resistance. Clinicians should await human trials before any prescription based on these findings. The proposed mechanism (gut-muscle axis via SCFAs) is biologically plausible but undemonstrated in humans.
Was noch fehlt
Randomized controlled trials in postmenopausal women with body composition, insulin resistance, and muscle function outcomes are needed. The clinically safe and effective dose of FFRB in humans remains unknown.