Sodium Ion Changes in the Skin of Rats Under High-Salt Diet Conditions and the Potential Mechanism of the Skin Acting as a Sodium Ion Buffer

Description

This dataset investigates the impact of a high-salt diet on sodium ion changes in the skin of rats and explores the role of the skin as a sodium ion buffer. The study includes detailed measurements of sodium and potassium ion concentrations in blood, urine, and skin, as well as analyses of glycosaminoglycans (GAGs), macrophage activity, lymphangiogenesis, and protein expressions related to the TonEBP/VEGF-C/VEGFR-3 pathway. Male SD rats were divided into five groups with varying dietary salt levels, including a transitional group shifting from high- to low-salt intake. Key findings include increased skin sodium levels and GAG concentrations under high-salt conditions, along with upregulated macrophage and lymphatic vessel markers. The dataset supports the hypothesis that the skin acts as a dynamic sodium reservoir, buffering blood pressure and sodium load, with lymphatic remodeling as a crucial mechanism. Data includes raw measurements, statistical analyses, and experimental protocols for sodium/potassium quantification, ELISA, immunofluorescence, and Western blotting, offering comprehensive insights into sodium homeostasis and related physiological pathways.

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Male SD rats (8 weeks old, SPF grade) were housed under controlled conditions (12-hour light/dark cycle, 23-25°C, 55-60% humidity) with free access to food and water. After one week of acclimation, they were divided into five groups: 0.1% low-salt, 0.8% normal-salt, 4% high-salt, 8% high-salt, and an 8% high-salt → 0.1% low-salt transitional group (high-salt diet for four weeks, then low-salt for four weeks). The study was approved by the Animal Ethics Committee of Anhui University of Chinese Medicine (Approval No.: AHUCM-rats-2023052). Blood pressure was measured non-invasively using a tail-cuff system at weeks 0, 2, 4, 6, and 8. Rats were pre-warmed to 38°C, and six readings were recorded for each rat, with the average used as the final value. Urine and blood were collected at designated intervals. Urine was centrifuged at 3500 rpm for 10 minutes, and serum was obtained from clotted blood samples after centrifugation. Sodium and potassium levels were measured using ion assay kits and spectrophotometry at 630 nm, calibrated with standard solutions. Skin samples were collected using sterile scalpels, dried, ashed, and dissolved for sodium and potassium quantification via atomic absorption spectroscopy. Standard curves were generated to calculate ion concentrations. Skin glycosaminoglycan (GAG) levels were measured using ELISA kits. Skin homogenates were centrifuged, and supernatants were processed following the ELISA protocol. Absorbance at 450 nm was measured, and GAG levels were calculated using a standard curve. Body fluid distribution (total body water, extracellular fluid, intracellular fluid) was measured using the Vet BIS1 bioimpedance analyzer. Electrodes were placed on anesthetized rats, and data were analyzed with ImpediVet BIS1 software. Immunofluorescence staining was performed to detect LYVE-1 (lymphatic marker) and F4/80 (macrophage marker) in skin sections. Samples were permeabilized with Triton X-100, blocked, and incubated overnight at 4°C with primary antibodies (1:100). Secondary antibodies were applied the next day, followed by fluorescence microscopy and ImageJ analysis. Western blotting was used to assess TonEBP, VEGF-C, VEGFR-3, and LYVE-1 protein levels. Skin proteins were extracted, separated by SDS-PAGE, and transferred to PVDF membranes. Membranes were blocked, incubated overnight with primary antibodies (1:1000), and treated with HRP-conjugated secondary antibodies (1:5000) for 1.5 hours. Protein bands were visualized using an imaging system and quantified with ImageJ. Data were analyzed using GraphPad Prism 9.5.0. Results were expressed as mean ± standard deviation. One-way ANOVA or Dunnett’s T3 test was used, with P < 0.05 considered significant.

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