Achyranthes Bidentata Polysaccharides Attenuates Hypoxic Renal Injury by Reducing Neutrophil Extracellular Traps Suppressing the NLRP3/ASC/Caspase-1 Pathway:A Preliminary Study

Kai LI^1,2Jing-Wei FANG²Guang-Min XIE²Jun-Ying LV^2*Fang-Ning Wei^1,3*

• ¹Guangzhou University of Chinese Medicine, Guangzhou, China
• ²Department of Traditional Chinese Medicine, First Affiliated Hospital, Guangxi Medical University, Guangxi, China
• ³Department of nephrology, The Second Clinical Medical School, Guangzhou University of Chinese Medicine, Guangzhou, China

ABSTRACT Aim: Aimed to investigate whether Achyranthes bidentata polysaccharides (ABPS) alleviate HRI and the possible mechanism. Methods: The HRI rat model was established using a hypobaric hypoxia chamber. Rats were divided into control group, Hypoxia group, low-dose ABPS group, high-dose ABPS group, DNase I positive control group, and NLRP3 agonist nigericin sodium salt (NSS) group. Blood serum of neutrophil extracellular traps (NETs) relevant components included cell-free DNA (cf-DNA), myeloperoxidase-DNA (MPO-DNA) and neutrophil elastase-DNA (NE-DNA), citrullinated histone 3 (citH3), blood urea nitrogen (BUN), serum creatinine (Scr), cystatin C (CysC), neutrophil gelatinase-associated lipocalin (NGAL), and kidney injury molecule-1 (KIM-1) were analyzed. NOD-like receptor protein 3 (NLRP3) pathway proteins, MPO, NE, citH3 and reactive oxygen species (ROS) of renal tissues were analyzed by multiplex fluorescence immunohistochemistry. MPO, and citH3 of renal tissues were analyzed via Western blot. Oxidative stress markers such as malondialdehyde (MDA), superoxide dismutase (SOD) were analyzed by Thio 3 barbituric acid (TBA) assay. Results: The results demonstrated that ABPS exerted protective effects against hypoxic renal injury. First, ABPS significantly reduced the levels of cf-DNA, MPO-DNA and cit-H3, with efficacy comparable to DNase I. Second, ABPS markedly suppressed the activation of the NLRP3 inflammasome pathway by degrading NETs, as evidenced by reduced protein expression of NLRP3, apoptosis-associated spot-like protein containing the CARD (ASC), and Caspase-1, accompanied by significant decreases in interleukin 1β (IL-1β) and IL-18. Furthermore, ABPS effectively alleviated oxidative stress by lowering MDA, enhancing SOD activity, and attenuating ROS. Finally, these molecular and cellular improvements translated into functional recovery, as high-dose ABPS treatment restored renal function to near-normal levels, including a 58.1% reduction in BUN, a 34.5 % reduction in Scr, a 23.6% reduction in NGAL, a 29.6% reduction in KIM-1, and a 32.2% reduction in CysC. HE and PAS staining and quantitative scoring analysis of kidney injury revealed severe tubular necrosis and glomerular damage in hypoxia group rats, which were significantly attenuated in both ABPL and ABPH groups (P<0.05). Conclusion: ABPS mitigates hypoxic renal injury by reducing NETs and synergistically regulating oxidative stress. ABPS shows potential as a multi-target, low-toxicity candidate for renal protection.