Minerva Medica 2020 Jul 17

DOI: 10.23736/S0026-4806.20.06625-2

Copyright © 2020 EDIZIONI MINERVA MEDICA

language: English

Inhibiting MiR-34α reduces retinal cell apoptosis and downstream NF-κB pathway in diabetic retinopathy rats through regulating HMGB1 expression

Yibin MA ¹, Yunhong DU ¹, Qian XU ¹, Huijing BAO ¹, Zhonglian LIU ², Yingchao LI ¹, Wenjing LIU ¹ ✉

¹ Department of Ophthalmology, Taian City Central Hospital, Taian, China; ² Radiotherapy Center, Taian Oncology Hospital, Taian, China

BACKGROUND: To study the effect of micro ribonucleic acid (miR)-34α on the retinal cell apoptosis in diabetic retinopathy (DR) rats and its key molecular mechanism.
METHODS: Sprague-Dawley rats were randomly divided into healthy group (H group, n=5), diabetes group (D group, n=5), diabetes + negative control transfection group (N group, n=5) and diabetes + miR-34α inhibitor transfection group (M group, n=5). The rat model of diabetes was established via intraperitoneal injection of 2% streptozotocin solution (60 mg/kg). After 72 h, the urine glucose and blood glucose were detected, and the urine glucose above 3+ and the blood glucose concentration >16.7 mmol/L indicated the successful modeling. After the rats were normally fed for 4 months, the changes in expression of miR-34α in retinal tissues were detected via reverse transcription-polymerase chain reaction (RT-PCR), the pathological changes in retinal tissues were observed via hematoxylin-eosin (HE) staining, and the retinal cell apoptosis was detected using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. Moreover, the changes in the number of cells containing active caspase-3 in retinal tissues were determined through immunohistochemistry, and the changes in expressions of caspase-3, high mobility group box 1 (HMGB1) and nuclear factor-κB (NF-κB) in retinal tissues were determined through Western blotting.
RESULTS: Compared with those in H group, the cell density declined and the cells were arranged disorderly with swelling in each retinal layer, the expression of miR-34α in retinal tissues was increased, the retinal cell apoptosis was enhanced, the number of cells containing active caspase-3 in retinal tissues rose, and the expressions of caspase-3, HMGB1 and NF-κB in retinal tissues were increased in D group, N group and M group (P<0.05). Compared with those in D group and N group, the cell density rose and the cells were arranged less disorderly with milder swelling in each retinal layer, the expression of miR-34α in retinal tissues declined, the retinal cell apoptosis was weakened, the number of cells containing active caspase-3 in retinal tissues was decreased, and the expressions of caspase-3, HMGB1 and NF-κB in retinal tissues were reduced in M group (P<0.05).
CONCLUSIONS: Inhibiting miR-34α reduces the retinal cell apoptosis in DR rats through egulating the HMGB1 expression and downstream NF-κB pathway.

KEY WORDS: miR-34α; Diabetic retinopathy; Retinal cell apoptosis; HMGB1, NF-κB