Effect of Shuangdan Mingmu Capsule on Diabetic Retinopathy in Rats via Regulation of miRNAs

Abstract

Purpose

To evaluate the effects of Shuangdan Mingmu (SDMM) capsule on diabetic retinopathy in rats by regulating miRNAs.

Materials and Methods

Streptozotocin (STZ) (50 mg/kg) was successfully used to induce diabetes in male Sprague-Dawley rats, which were randomly assigned to a group taking SDMM capsules (“diabetic+SDMM”) or a control group (“diabetic”), and the normal group (n=10/group). The diabetic+SDMM capsule group received 1.89g/kg/d of SDMM capsule by gavage, whereas the other groups received the same amount of distilled water. After 12-weeks of gavage, the retina was removed from all rats for histopathological analysis, and miRNA sequencing experiments were carried out to identify the differential expression of miRNAs. These results were then confirmed by quantitative real-time polymerase chain reaction (qRT-PCR).

Results

SDMM capsules improved retinal morphology, restored the number of cells in the ganglion cell layer (p<0.0001) and reduced apoptosis in all retinal layers (p values in the outer nuclear layers, inner nuclear layers and ganglion cell layers 0.0001, 0.0147, 0.0034, respectively). In addition, miRNA expression was changed in rats taking SDMM capsules. Compared with the diabetic group, six miRNAs were up-regulated and four miRNAs were down-regulated in the diabetic+SDMM capsule group. The qRT-PCR validation results showed that the expression levels of miR-450b-5p, miR-1249 and miR-155-5p were consistent with the trend of miRNA sequencing results, and were all up-regulated after SDMM capsule treatment. Target gene prediction and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of differentially expressed miRNAs showed that these pathways were mainly concentrated in the focal adhesions and PI3K/Akt, MAPK, and neural factor signaling pathways.

Conclusion

SDMM capsules may prevent and treat diabetic retinopathy by regulating the expression of miR-450b-5p, miR-1249 and miR-155-5p.

Keywords:

• SDMM capsule
• diabetic retinopathy
• traditional Chinese medicine
• miRNAs
• bioinformatics analysis

Abbreviations

SDMM, Shuangdan Mingmu; KEGG, Kyoto Encyclopedia of Genes and Genomes; DR, Diabetic retinopathy; TCM, Traditional Chinese medicine; HE, Hematoxylin-Eosin; PAS, Periodic Acid-Schiff; TUNEL, TdT-mediated dUTP nick end labeling; qRT-PCR, quantitative real-time polymerase chain reaction; GCL, ganglion cell layer; INL, inner nuclear layer; ONL, outer nuclear layer; VEGF, Vascular Endothelial Growth Factor; PEDF, Pigment Epithelium Derived Factor.

Acknowledgments

We appreciate the support of LHP who providing us with preliminary data on components absorbed into the plasma of SDMM capsule.

Author Contributions

All authors contributed to data analysis, drafting or revising the article, have agreed on the journal to which the article will be submitted, gave final approval of the version to be published, and agree to be accountable for all aspects of the work.

Disclosure

The authors declare no competing financial interests.

Additional information

Funding

This research was supported by the National Natural Science Foundation of China (No. 81874493), Hunan Provincial Graduate Student Research Innovation Program (No.CX20210696), Hunan Provincial Natural Science Foundation Youth Project (No.2020JJ5413), Outstanding Youth Program for Scientific Research of Hunan Provincial Department of Education (No.19B431).