Quercetin ameliorates testosterone secretion disorder by inhibiting endoplasmic reticulum stress through the miR-1306-5p/HSD17B7 axis in diabetic rats.

Testicular damage and testosterone secretion disorder are associated with diabetes mellitus. Quercetin,  a common flavonoid, has antioxidant, anti-cancer,  and blood sugar lowering effects. Therefore, this study aims to investigate the effect of quercetin on the reproductive system of male rats with diabetes in vivo and in vitro and elucidate its mechanism. Streptozotocin (STZ)  induction was used to establish a diabetes model in forty male Sprague Dawley (SD) rats, which were subsequently administered with 20 or 50 mg/kg of quercetin. Leydig cells of rat testes were treated by high glucose (HG) followed by 5 or 10 µM quercetin. Two doses of quercetin increased rat body weight and testicular weight, decreased blood glucose,and inhibited oxidative stress. RT-qPCR and Western blotting revealed that quercetin alleviated STZ-induced testicular damage and promoted testosterone synthesis. Both doses of quercetin reduced ROS and MDA levels, and increased SOD level in HG-treated cells. Both, in vivo and in vitro results confirmed that a high dose of quercetin was more effective. MiR-1306-5p was upregulated in testicular tissue of diabetic rats and HG-treated cells. 17ß-hydroxysteroid dehydrogenase (HSD17B7) was a target of miR-1306-5p and HSD17B7 was downregulated in STZ-induced rat tissues and HG-treated cells. HSD17B7 overexpression reversed the increase of C/EBP homologous protein (CHOP) and glucose-regulated protein 78 (Grp78) protein levels as well as eIF2α phosphorylation level and promotion of cell apoptosis caused by miR-1306-5p overexpression. Moreover, overexpression of HSD17B7 activated the Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) axis in HG-treated cells. In conclusion, quercetin inhibits ER stress and improves testosterone secretion disorder through the miR-1306-5p/HSD17B7 axis in diabetic rats.

Long Non-coding RNA XIST Attenuates Diabetic Peripheral Neuropathy by Inducing Autophagy Through MicroRNA-30d-5p/sirtuin1 Axis.

Diabetic peripheral neuropathy (DPN) is a prevalent diabetes mellitus (Feldman et al., 2017) complication and the primary reason for amputation. Meanwhile, long non-coding RNAs (lncRNAs) are a type of regulatory non-coding RNAs (ncRNAs) that broadly participate in DPN development. However, the correlation of lncRNA X-inactive specific transcript (XIST) with DPN remains unclear. In this study, we were interested in the role of XIST in the modulation of DPN progression. Significantly, our data showed that the expression of XIST and sirtuin1 (SIRT1) was inhibited, and the expression of microRNA-30d-5p (miR-30d-5p) was enhanced in the trigeminal sensory neurons of the diabetic mice compared with the normal mice. The levels of LC3II and Beclin-1 were inhibited in the diabetic mice. The treatment of high glucose (HG) reduced the XIST expression in Schwann cells. The apoptosis of Schwann cells was enhanced in the HG-treated cells, but the overexpression of XIST could block the effect in the cells. Moreover, the levels of LC3II and Beclin-1 were reduced in the HG-treated Schwann cells, while the overexpression of XIST was able to reverse this effect. The HG treatment promoted the production of oxidative stress, while the XIST overexpression could attenuate this result in the Schwann cells. Mechanically, XIST was able to sponge miR-30d-5p and miR-30d-5p-targeted SIRT1 in the Schwann cells. MiR-30d-5p inhibited autophagy and promoted oxidative stress in the HG-treated Schwann cells, and SIRT1 presented a reversed effect. MiR-30d-5p mimic or SIRT1 depletion could reverse XIST overexpression-mediated apoptosis and autophagy of the Schwann cells. Thus, we concluded that XIST attenuated DPN by inducing autophagy through miR-30d-5p/SIRT1 axis. XIST and miR-30d-5p may be applied as the potential targets for DPN therapy.

[Effect of endotoxemia on thyrotropin releasing hormone and its receptor in Wistar rat brain].

OBJECTIVE: To study the dose and location of thyrotropin releasing hormone (TRH) and its receptor in Wistar rat's brain when early endotoxemia happened. METHODS: Twenty-two Wistar rats were selected. In 13 mouse the model was established with endotoxemia and hemorrhagic shock. The TRH and its receptor were observed with radioimmunoassay (RIA), and were compared to the 9 control rats. RESULTS: The dose of TRH decreased significantly in the early stage of endotoxemia. The maxium dose (Bmax) of TRH increased while Kd (affinity) decreased, so the effective TRH receptor had no significantly change. CONCLUSION: The dose of TRH is different in brain and serum. The decrease of TRH and the steady of active TRH receptor may protect the brain tissue and repress multiple organ dysfunction syndrome (MODS) in the early stage of endotoxemia.