A Low-Frequency Pulsed Magnetic Field Reduces Neuropathic Pain by Regulating NaV1.8 and NaV1.9 Sodium Channels at the Transcriptional Level in Diabetic Rats

Low-frequency pulsed magnetic field (LF-PMF) application is a non-invasive, easy, and inexpensive treatment method in pain management. However, the molecular mechanism underlying the effect of LF-PMF on pain is not fully understood. Considering the obvious dysregulations of gene expression observed in certain types of voltage-gated sodium channels (VGSCs) in pain conditions, the present study tested the hypothesis that LF-PMF shows its pain-relieving effect by regulating genes that code VGSCs proteins. Five experimental rat groups (Control, Streptozotocin-induced experimental painful diabetic neuropathy (PDN), PDN Sham, PDN 10 Hz PMF, and PDN 30 Hz PMF) were established. After the pain formation in PDN groups, the magnetic field groups were exposed to 10/30 Hz, 1.5 mT PMF for 4 weeks, an hour daily. Progression of pain was evaluated using behavioral pain tests during the entire experimental processes. After the end of PMF treatment, SCN9A (NaV_1.7 ), SCN10A (NaV_1.8 ), SCN11A (NaV_1.9 ), and SCN3A (NaV_1.3 ) gene expression level changes were determined by analyzing real-time polymerase chain reaction results. We found that 10 Hz PMF application was more effective than 30 Hz on pain management. In addition, NaV_1.7 and NaV_1.3 transcriptions were upregulated while NaV_1.8 and NaV_1.9 were downregulated in painful conditions. Notably, the downregulated expression of the genes encoding NaV_1.8 and NaV_1.9 were re-regulated and increased to control level by 10 Hz PMF application. Consequently, it may be deduced that 10 Hz PMF application reduces pain by modulating certain VGSCs at the transcriptional level. © 2021 Bioelectromagnetics Society.

Changes in sperm quality and testicular structure in a rat model of type 1 diabetes

Background

Chronic hyperglycemia is a characteristic of diabetes mellitus (DM). Long-lasting hyperglycemia can generate oxidative stress and reactive oxygen species. The effect of this condition on sperm quality and spermatogenesis leads to male infertility and reproductive dysfunction.

Objectives

To investigate changes in sperm quality, morphology of testicular structure, and stage of development of seminiferous tubules in a streptozotocin (STZ)-induced rat model of type 1 DM.

Methods

We divided 15 male Sprague Dawley rats into 2 groups. DM was induced in 7 rats using STZ (60 mg/kg intraperitoneally), while the other 8 were treated with citrate buffer as a vehicle control group. Rat semen was collected for quality measurements including motility, normal morphology, and concentration. Morphological changes in testicular structure and stage of development of seminiferous tubules were investigated by histology with hematoxylin and eosin (HE) staining.

Results

Significant decreases in all parameters of sperm quality and testicular weight were found in rats with induced DM. Moreover, abnormal morphology of seminiferous tubules including separation of the germinal epithelium, vacuolization, luminal sloughing of germ cells, and tubular atrophy was increased significantly in these rats, while the proportion of their seminiferous tubules at an early stage of development was significantly higher, but was dramatically decreased in the late stage of development when compared with that in vehicle-treated control rats.

Conclusions

DM has adverse effects on sperm quality, testicular structure, and development of seminiferous tubules. These findings may reflect the male infertility and reproductive dysfunction seen in patients with type 1 DM.