| Objective To investigate the relationship between the expression of epigenetic signaling molecule-bromodomain protein 4 (BRD4) and the efficacy of the Six-Ingredient Rehmannia Pill on the treatment of postmenopausal osteoporosis (PMOP). Methods A PMOP rat model was established with bilateral ovariectomy. The rats were then randomly divided into sham-operated group, model group (saline, 10 mL/kg), model Chinese medicine group (Six-Ingredient Rehmannia Pill, 385.7 mg/kg), and model Western medicine group (alendronate 0.893 mg/kg), with 15 rats in each group. Femoral specimens were taken from the Chinese medicine and Western medicine groups after 12 weeks of the treatment to detect femoral bone mineral density, bone strength, and the expression of BRD4 protein in the bone tissue. The BRD4 expression and significance were analyzed with the PMOP TCM kidney deficiency evidence sequencing dataset GSE56116. Results Western blotting results showed that BRD4 protein expression levels were up-regulated in the PMOP model group compared to those in the sham-operated rats, and the difference was significant (P<0.05). Compared to those in the PMOP model rats, BRD4 protein expression levels were down-regulated in Chinese medicine group and Western medicine group. Analysis of the GSE56116 dataset revealed that BRD4 mRNA expression was significantly higher in the kidney yin deficiency group than that in the kidney yang deficiency group and the non-kidney deficiency group, and the difference was significant (P<0.05). The upregulation of BRD4 expression involved 5-hydroxytryptaminergic synapses, platelet activity, neural ligand receptor responses, calcium signaling pathways, and the second messenger-mediated signaling. Conclusion BRD4 expression level is correlated with the efficacy of the Six-Ingredient Rehmannia Pill on the treatment of PMOP with kidney yin deficiency evidence. |