Transcranial direct current stimulation improves cerebral ischemiareperfusion injury by regulating microglial ferroptosis and M1 polarization via KLF4/xCT

  • Pathol Res Pract. 2026 Jun 22:286:156598. doi: 10.1016/j.prp.2026.156598.
Yongjun Gao  1 ,  Xiuli Han  2 ,  Yong Yuan  3 ,  Pengyan Guo  3 ,  Pengyu Qiao  3 ,  Renhui Shang  3 ,  Xinhai Gao  3 ,  Kuai Yu  3
Affiliations
  • 1. Department of Neurosurgery, The Second Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650101, China. Electronic address: [email protected].
  • 2. Department of Stomatology, Children's Hospital Affiliated to Kunming Medical University, Kunming, Yunnan 650000, China.
  • 3. Department of Neurosurgery, The Second Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650101, China.
PMID: 42364340 DOI: 10.1016/j.prp.2026.156598
Abstract

Background: Neuroinflammation triggered by microglia plays a critical role in cerebral ischemia-reperfusion injury (CIRI). Previous studies have reported that transcranial direct current stimulation (tDCS) has ameliorative effects on CIRI, but its regulatory effect on microglia in CIRI remains poorly understood.

Methods: A middle cerebral artery occlusion/reperfusion (MCAO/R)-induced CIRI rat model and an oxygenglucose deprivation/reperfusion (OGD/R)-induced BV2 cell injury model were established for experimental investigation. The severity of CIRI in rats and cell damage were assessed using the mNSS, TTC staining, HE staining, Nissl staining, CCK-8, and immunofluorescence. The expression levels of related proteins and cytokines were determined via Western blotting, immunohistochemistry, and ELISA.

Results: First, tDCS treatment effectively improved CIRI in rats and inhibited M1 polarization of microglia in the ischemic penumbra. Second, Ferroptosis plays an important role in OGD/R-induced BV2 cell death, and direct current stimulation (DCS) significantly suppressed OGD/R-induced Ferroptosis in BV2 cells. Additionally, DCS inhibited the expression of M1 polarization markers and proinflammatory factors in BV2 cells while promoting the expression of M2 polarization markers and anti-inflammatory factors. Mechanistically, we found that KLF4 expression was downregulated in CIRI and that tDCS treatment upregulated KLF4 expression. Knockdown of KLF4 partially attenuated the therapeutic effects of tDCS on CIRI in rats. Furthermore, overexpression of KLF4 inhibited Ferroptosis and M1 polarization in BV2 cells by promoting xCT expression.

Conclusion: tDCS ameliorates CIRI in rats by suppressing microglial Ferroptosis and M1 polarization through the activation of KLF4/xCT expression.

Keywords
Cerebral ischemiareperfusion injury; Ferroptosis; KLF4/xCT; M1 polarization; Microglia; TDCS.
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