DCA can improve the ACI-induced neurological impairment through negative regulation of Nrf2 signaling pathway

To investigate the effect of tauroursodeoxycholic acid (TUDCA) on neurological impairment induced by acute cerebral infarction (ACI) and its relevant mechanism of action.

A total of 60 male Sprague-Dawley (SD) rats were randomly divided into Sham group (n = 20), ACI group (n = 20), and TUDCA group (n = 20). The rat model of ACI in middle cerebral artery was established. TUDCA was intravenously injected into rats in the TUDCA group, while an equal amount of sodium bicarbonate solution was intravenously injected into the other two groups. The blood was drawn after modeling to detect the content of serum glutamate (Glu), triglyceride (TG), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C). The degree of cerebral infarction in each experimental group was observed under an optical microscope, and the infarct area was measured and compared. The content of serum tumor necrosis factor-α (TNF-α), interleukin-8 (IL-8), and high-sensitivity C-reactive protein (hs-CRP) was detected via enzyme-linked immunosorbent assay (ELISA); mRNA and protein expressions of them were detected using reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting, respectively, followed by statistical analysis. Moreover, the expression levels of serum malondialdehyde (MDA), oxidized-LDL (ox-LDL), superoxide dismutase (SOD), and glutathione peroxidase (GPX) were detected, followed by statistical analysis. The protein expressions of nuclear factor (erythroid-derived 2)-like 2 (Nrf2), very low-density lipoprotein receptor (VLDLR), nuclear factor-κB (NF-κB), B-cell lymphoma 2-associated X protein (Bax), and caspase-3 were detected via Western blotting, and the gray value was determined, followed by statistical analysis.

TUDCA could improve the symptoms of neurological impairment in ACI patients, decrease the National Institute of Health Stroke Scale (NIHSS) score but increase the activity of daily living (ADL) score of patients, and significantly reduce the content of serum TG, TC, and LDL-C, showing statistically significant differences (p < 0.05). TUDCA significantly decreased the serum Glu content in ACI rats, reduced the cerebral infarction area and lowered the serum TG, TC, and LDL-C content, displaying statistically significant differences (p < 0 .05). Besides, TUDCA inhibited mRNA and protein expressions of TNF-α, IL-8, and hs-CRP, and alleviated the inflammatory response. TUDCA inhibited MDA and ox-LDL expressions, but increased SOD and GPX expressions, and relieved oxidative stress injury. In addition, TUDCA could negatively regulate Nrf2 signaling pathway, and down-regulated VLDLR and NF-κB protein expressions and expressions of apoptotic proteins (Bax and caspase-3).

TUDCA can alleviate the ACI-induced neurological impairment in rats through mitigating lipid peroxidation and inflammatory response and reducing apoptosis, whose relevant mechanism may be that TUDCA negatively regulates Nrf2 signaling pathway.