Neuroprotective and immunomodulatory effects of human hair follicle stem cells on streptozotocin-induced memory impairment in rats: insights into inflammation and neurotrophic mechanisms

This study explored the potential of human hair follicle stem cells (hHFSCs) as a treatment for memory impairment caused by streptozotocin (STZ) in male rats. Alzheimer’s disease, a major cause of dementia, involves neurodegeneration and inflammation, prompting researchers to investigate neuroprotective strategies. Rats were divided into control, STZ, and STZ + hHFSC groups, with stereotaxic intracerebroventricular injections of STZ (3 mg/kg) or vehicle. hHFSCs (1×10 ⁶ ) were transplanted on days 4, 14, and 21 post-surgery. Memory function was assessed via passive avoidance tests, showing notable improvement in hHFSC-treated rats compared to STZ-treated rats. Molecular analyses of hippocampal tissue revealed increased expression of neurotrophic factors such as BDNF, TGFβ, and GFAP as well as inflammatory markers including IL-1β, IL-6, and TNFα. Elevated TGFβ and GFAP in the STZ group persisted after stem cell transplantation, indicating a continued neuroinflammatory response, while IL-10 levels rose, suggesting anti-inflammatory effects of hHFSC treatment. These findings suggest that hHFSCs exhibit neuroprotective effects against STZ-induced memory impairment. The simultaneous upregulation of pro- and anti-inflammatory markers underscores the complexity of the inflammatory response in this xenogeneic model. Future investigations should consider immunocompromised models or immunosuppressive protocols to better isolate the therapeutic effects of hHFSCs from immune responses.