Both selenium deficiency and excess impair male reproductive system via inducing oxidative stress-activated PI3K/AKT-mediated apoptosis and cell proliferation signaling in testis of mice.

Selenium (Se) deficiency or excess impairs testicular development and spermatogenesis, while the underlying mechanisms in this regard remain unclear. This study was designed to explore the molecular biology of Se deficiency or excess in spermatogenesis in mice. Three-week-old male mice (n = 10 mice/diet) were fed with Se-deficient diet (SeD, 0.02 mg Se/kg), adequate-Se diet (SeA, 0.2 mg Se/kg), or excess-Se diet (SeE, 2.0 mg Se/kg) for 5 months. Compared with SeA, SeD reduced (P < 0.05) the body weight (10.4%) and sperm density (84.3%) but increased (P < 0.05) sperm deformity (32.8%); SeE decreased (P < 0.05) the sperm density (78.5%) and sperm motility (35.9%) of the mice. Meanwhile, both SeD and SeE increased (P < 0.05) serum FSH concentrations (10.4-25.6%) and induced testicular damage in mice in comparison with the SeA. Compared with SeA, SeD increased (P < 0.05) the 8-OHdG concentration by 25.5%; SeE increased (P < 0.05) both MDA and 8-OHdG concentrations by 118.8-180.3% in testis. Furthermore, transcriptome analysis showed that there 1325 and 858 transcripts were altered (P < 0.05) in the testis by SeD and SeE, respectively, compared with SeA. KEGG pathway analysis revealed that these differentially expressed genes were mainly enriched in the PI3K-AKT signaling pathway, which is regulated by oxidative stress. Moreover, western blotting analysis revealed that SeD and SeE dysregulated PI3K-AKT-mediated apoptosis and cell proliferation signaling, including upregulating (P < 0.05) caspase 3, cleaved-caspase 3, BCL-2 and (or) P53 and downregulating (P < 0.05) PI3K, p-AKT, p-mTOR, 4E-BP1, p-4E-BP1 and (or) p-p70S6K in the testis of mice compared with SeA. Additionally, compared with SeA, both SeD and SeE increased (P < 0.05) GPX3 and SELENOO; SeD decreased (P < 0.05) GPX1, TXRND3 and SELENOW, but SeE increased (P < 0.05) production of three selenoproteins in the testis. Conclusively, both Se deficiency and excess impairs male reproductive system in mice, potentially with the induction of oxidative stress and activation of PI3K/AKT-mediated apoptosis and cell proliferation signaling in the testis.

Upregulation of Myeloid Zinc Finger 1 in Dorsal Root Ganglion via Regulating Matrix Metalloproteinase-2/9 and Voltage-gated Potassium 1.2 Expression Contributes to Complete Freund's Adjuvant-induced Inflammatory Pain.

Myeloid zinc finger 1 (MZF1) belongs to the Kruppel family of zinc-finger transcription factors. Recent studies have demonstrated that in dorsal root ganglion (DRG) neurons, MZF1 is involved in the development and maintenance of neuropathic pain. However, the role of MZF1 in inflammatory pain still remains unknown. In the present study, the mechanism of MZF1 in chronic inflammatory pain was investigated in rats received an intraplantar injection of complete Freund's adjuvant (CFA). Subsequently, a series of assays including Western blotting, qRT-PCR, immunohistochemistry, and chromatin immunoprecipitation (ChIP) were performed. We found that CFA led to MZF1 upregulation in ipsilateral L4/5 DRGs. Pre- and post-microinjection of MZF1 siRNA into the ipsi-L5 DRG blocked the development of CFA-induced chronic inflammatory pain and alleviated the mechanical allodynia and thermal hyperalgesia in the maintenance phase. CFA also increased MMP-2/9 and Nav1.8 expression but reduced voltage-gated potassium 1.2 (Kv1.2) and Cav1.2 expression in L4/L5 DRGs. Microinjection of MZF1 siRNA into DRG diminished the CFA-induced changes in MMP-2/9 and Kv1.2 expression. However, the expressions of Nav1.8 and Cav1.2 were not changed by the treatment. Double immunofluorescence staining showed that MMP-2/9 and Kv1.2 were co-localized with MZF1 in DRGs. The ChIP-PCR results revealed that MZF1 binds directly to the promoter region of MMP-2/9 gene. Together, the above results imply that upregulation of MZF1 in DRGs might contribute to the development and maintenance of CFA-induced chronic inflammatory pain by regulating MMP-2/9 and Kv1.2 expression. Targeting DRG-localized MZF1 might be a promising therapeutic strategy for the treatment of chronic inflammatory pain in the clinic.