[Effects of high salt diet on renal vascular reactivity in mice detected by laser speckle contrast imaging].

The aim of this study was to conduct <i>in vivo</i> experiments using laser speckle contrast imaging (LSCI) technology to investigate the effects of high salt diet on renal vascular reactivity in mice. LSCI is a technology for monitoring blood flow based on the laser speckle principle. It has been widely used to detect microcirculatory functions in tissues such as the skin and brain. The kidneys are located behind the peritoneum, and their position is easily affected by the movement of abdominal organs. Measuring renal microcirculation in a living individual is difficult. The present study used a self-made kidney cup to isolate the kidney and fix its position relatively, and then applied LSCI technology to explore the effect of high salt diet (8% Na⁺) on renal vascular reactivity in male and female mice <i>in vivo</i>. The results showed that a short-term high salt diet (1 week) did not affect the systolic blood pressure of the tail artery, while significantly increased glomerular filtration rate (GFR) and renal blood flow (RBF). Compared with the normal salt diet group, the high salt diet group showed a significant decrease in the ratio of post-occlusive reactive hyperemia (PORH) in male mice, while there was no significant change in the PORH ratio in female mice. These results suggest that, although a short-term high salt diet does not cause changes in blood pressure, it has already affected renal vascular reactivity and has gender differences in its effects. Furthermore, the present study provides a basis for renal microcirculation assessment using LSCI <i>in vivo</i>.