Background: Polycystic ovary syndrome (PCOS) is one of the most common
endocrine and metabolic diseases of women of reproductive age. The major
characteristics of PCOS are anovulation, hyperandrogenism, infertility, and insulin
resistance. Previous studies showed that acupuncture could promote menstruation,
decrease testosterone levels, increase insulin sensitivity, and improve frequency of
ovulation in women with PCOS. However, the mechanism of how acupuncture
regulates the reproductive and metabolic abnormalities of PCOS remains unclear. The
present study investigated the differential expression of miRNAs in the ovaries of rats
with PCOS and insulin resistance (IR) after electroacupuncture (EA) treatment.
Methods: A rat model of PCOS with IR was established by letrozole and a high-fat
diet. Rats in the PCOS+EA group received acupuncture treatment five times a week for
four weeks. The differentially expressed miRNAs of three rat ovaries of each group
(n=3/group) were identified by deep sequencing. The differentially expressed miRNAs
are shown by a hierarchical clustering heatmap and volcano plot. Gene ontology (GO)
analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis
were conducted to explore the potential target genes of the differentially expressed
miRNAs and identify their putative biological function. Eight of the differentially
expressed miRNAs were selected for validation by real-time quantitative PCR (qRTPCR).
Results: The rats in the PCOS+EA group had significantly decreased body weight and
increased insulin sensitivity compared with the rats in the PCOS group. EA tend to
reduce testosterone levels in the rats with PCOS and insulin resistance. The rats in the
PCOS+EA group displayed fewer large cystic follicles, fewer atretic antral follicles,
and more corpora lutea than the rats in the PCOS group. A total of 23 differentially
expressed miRNAs were identified in the PCOS with IR group after EA treatment,
including 15 miRNAs that were upregulated and 8 miRNAs that were downregulated.
GO and KEGG pathway analyses indicated that the predicted target genes were related
to cellular processes, and metabolic pathways. Furthermore, qRT-PCR confirmed that
miRNA-181 was significantly downregulated in the rat ovaries of the PCOS+EA group
compared with the PCOS group.
Conclusion: Our results indicate that differentially expressed miRNAs may mediate the effect of acupuncture on insulin sensitivity in PCOS with IR. It will be beneficial to study the mechanism of acupuncture in improving insulin resistance in women with PCOS.