Safflower Extract Mitigates MIRI in Rats by Modulating TLR-4/NF-κB Signaling Pathway, Demonstrating Protective Effects.

BACKGROUND

Myocardial ischemia-reperfusion injury (MIRI) exacerbates tissue damage following the restoration of coronary blood flow after ischemia. The TLR-4/NF-κB signaling pathway plays a crucial role in the pathogenesis of MIRI. This study investigated the therapeutic efficacy of safflower extract in mitigating MIRI and its modulation of TLR-4/NF-κB signaling in rats.

METHODS

Adult male Sprague-Dawley rats were subjected to 30 minutes of myocardial ischemia followed by 2 h of reperfusion. Safflower extract was administered intravenously at doses of 2, 4, and 8 mg/kg 15 minutes before ischemia and 1 minute before reperfusion. Infarct size was assessed using TTC staining. Serum levels of creatine kinase (CK) and lactate dehydrogenase (LDH) were measured. Pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) were quantified using ELISA. TLR-4 and NF-κB mRNA and protein expression were evaluated using qRT-PCR and western blotting, respectively. Histopathological changes were assessed using H&E staining.

RESULTS

Safflower extract effectively reduced myocardial infarct size in a dose-dependent manner, with the highest dose providing the greatest benefit. Treatment with safflower extract significantly lowered the elevated levels of serum CK and LDH caused by ischemia-reperfusion (I/R) injury, bringing these biochemical markers closer to normal values. In addition, safflower extract decreased the levels of pro-inflammatory cytokines IL-1β, IL-6, and TNF-α in myocardial tissue, showing a clear dose-response relationship. Analysis through qRT-PCR and western blot confirmed that safflower extract downregulated the expression of TLR4 and NF-κB at both the transcriptional and protein levels. Histological studies further supported these findings, demonstrating that safflower extract improved myocardial tissue architecture, maintained cardiomyocyte structure, and reduced inflammatory cell infiltration.

CONCLUSION

Safflower extract provides significant cardioprotection against MIRI by modulating the TLR-4/NF-κB-mediated inflammatory response. These findings suggest that safflower extract may be a potential therapeutic agent for mitigating the effects of myocardial ischemiareperfusion injury.