关键词:

核苷酸结合结构域富含亮氨酸重复序列和含热蛋白结构域受体3, 炎症小体, Klotho蛋白, 自发性高血压大鼠, 肾脏功能, 肾损伤

Abstract:

Objective　To investigate the effects of Klotho protein on renal injury and nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome in spontaneous hypertensive rats (SHR). Methods　The experiment was conducted from January 10 to March 25, 2024. The 14-week-old SPF male spontaneously hypertensive rats with body mass of 220-260 g were selected, and the other SPF male WKY rats with the same body mass were selected. All rats were fed alone in a 12 h/12 h light-dark cycle at 25 ℃ and 60% humidity, and after 7 days of adaptive feeding, the rats were treated in groups at the same time in the morning during the following 21 days. The spontaneously hypertensive rats were divided into a model group (gavage with equal volume of normal saline), a positive control group (gavage with 0.67 mg/kg of enalapril), low and high dose Klotho groups (gavage with 50 and 100 mg/kg of Klotho), and a high dose Klotho+NLRP3 inflammasome activator group (gavage with 100 mg/kg of Klotho protein followed by 5 mg/kg of nigericin sodium), 12 rats in each group; another 12 WKY rats were selected as a control group (gavage with equal volume of normal saline). The rats in each group were given gavage once a day for 21 days, and other treatment methods were the same. The systolic and diastolic blood pressure of the tail artery, renal function (serum creatinine, blood urea nitrogen, and urinary microalbumin), pathological morphology of renal tissue, content of collagen fibers, levels of inflammatory factors [interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and IL-1β], Klotho protein, NLRP3, apoptosis-associated speck-like protein (ASC), Caspase-1, Collagen Ⅲ, and Collagen Ⅰ protein contents of each group were detected. One-way analysis of variance and LSD-t test were used for statistical analysis. Results　Compared with the control group, the model group had severe renal tissue damage, with increased tail artery systolic and diastolic blood pressure, serum creatinine, urea nitrogen, and urinary microalbumin contents, levels of inflammatory factors in renal tissue (IL-6, TNF-α, and IL-1β), Collagen volume fraction, and NLRP3, ASC, Caspase-1, Collagen Ⅲ, and Collagen Ⅰ protein expressions in renal tissue, and reduced Klotho protein expression level (0.24±0.01 vs. 0.60±0.02), with statistically significant differences (all P<0.05). Compared with the model group, the positive control group and low and high dose Klotho groups had reduced kidney tissue lesions, with reduced tail artery systolic and diastolic blood pressure, serum creatinine, urea nitrogen, and urinary microalbumin contents, levels of inflammatory factors in renal tissue (IL-6, TNF-α, and IL-1β), Collagen volume fraction, and NLRP3, ASC, Caspase-1, Collagen Ⅲ, and Collagen Ⅰ protein expressions in renal tissue, and increased Klotho protein expression level (0.53±0.03, 0.36±0.03, 0.51±0.04 vs. 0.24±0.01), with statistically significant differences (all P<0.05). Compared with the high dose Klotho group, the high-dose Klotho+NLRP3 inflammasome activator group had severe renal tissue damage, intensified renal fibrosis and inflammatory response, and decreased renal function (all P<0.05). Conclusion　Supplementing with Klotho protein can alleviate the renal tissue inflammation and fibrosis in spontaneously hypertensive rats by inhibiting the NLRP3 inflammasome pathway, thereby improving the renal injury and enhancing the renal function.

Key words:

Nucleotide-binding oligomerization domain-like receptor protein 3, Inflammasome, Klotho protein, Spontaneously hypertensive rats,  , Renal function, Renal injury