Hypertonic saline resuscitation protects against kidney injury induced by severe burns in rats.

BACKGROUND: Proper fluid resuscitation can relieve visceral damage and improve survival in severely burned patients. This study compared the effectiveness of resuscitation with 400mEq/L hypertonic saline (HS) and sodium lactate Ringer's solution (LR) in rats with kidney injury caused by burn trauma. METHODS: Rats (Sprague-Dawley) underwent burn injury and were randomized into sham, LR, and HS groups. Samples from the kidney were assayed for water content ratio, histopathology, and oxidative stress (superoxide dismutase (SOD) and malondialdehyde (MDA)). Serum sodium, renal function (creatinine and cystatin (Cys)-C), and inflammatory response (tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, and high mobility group protein box (HMGB)-1) were also examined as serum markers. RESULTS: Hypertonic saline resuscitation reduced the renal water content ratio and improved renal histopathology caused by severe burns. This effect was accompanied by reductions in serum creatinine and Cys-C as well as TNF-α, IL-1ß, and HMGB1. Serum sodium concentration and SOD activity were increased, whereas MDA content was decreased in the kidney tissue of the HS group. CONCLUSIONS: The data indicate that 400mEq/L HS solution reduces hyponatremia and renal edema, inhibits the release of inflammatory mediators, and alleviates oxidative stress injury, thus protecting against kidney injury induced by severe burns.

[Study on the mechanism of hypertonic salt solution alleviates lung injury of rats at the early stage of severe scald].

OBJECTIVE: To explore the mechanism of hypertonic salt solution (HS) alleviates lung injury of rats at the early stage of severe scald. METHODS: Thirty-two female Sprague-Dawley (SD) rats were randomly assigned to sham group, lactated Ringer solution (LR) group, HS200 group (200 mmol/L HS group, 1 L 200 mmol/L HS contained 955 mL LR and 45 mL 10% NaCl) and HS400 group (400 mmol/L HS group, 1 L 400 mmol/L HS contained 846 mL LR and 154 mL 10% NaCl), with 8 rats in each group. A 30% total body surface area (TBSA) III degree scalded model was reproduced by scalded on the back with 98 centigrade boiling water for 12 seconds, whereas those in the sham group were exposed to 37 centigrade water without liquid resuscitation. Rats in the three drug intervention groups were resuscitated with LR, 200 mmol/L HS and 400 mmol/L HS by caudal vein according to the Parkland formula, respectively. All rats were sacrificed at 8 hours after scald injury to harvest abdominal aorta blood and lung tissues. Interleukins (IL-6, IL-10 and IL-17) in serum were determined by enzyme-linked immunosorbent assay (ELISA). Samples from the lung tissue were used to measure malondialdehyde (MDA) and superoxide dismutase (SOD) levels by ultraviolet spectrophotometer. Expressions of p38 mitogen-activated protein kinase (p38MAPK) and extracellular regulated protein kinase 1/2 (ERK1/2) in the lung were determined by Western Blot. The lung tissue was stained with hematoxylin and eosin (HE), and the pathological changes were observed with a light microscope. RESULTS: Compared with the sham group, the lung tissues in the LR group were damage obviously, which accompanied with more inflammatory cell infiltration, cell edema and pulmonary septum thickening, and the levels of IL-6, IL-10, IL-17 in serum and MDA content, the phosphorylation of p38MAPK and ERK1/2 in lung tissues were increased whereas the activity of SOD was decreased. Compared with the LR group, the lung injury was significantly alleviated, the levels of IL-6, IL-17 in serum and MDA content and the phosphorylation of p38MAPK and ERK1/2 were decreased, and the levels of IL-10 and SOD were increased in both HS groups with a dose-dependent manner. There were significant difference in above parameters between HS400 group and LR group [serum IL-6 (ng/L): 3.76±0.12 vs. 6.72±0.90, serum IL-10 (ng/L): 33.76±3.71 vs. 16.77±3.19, serum IL-17 (ng/L): 103.52±2.78 vs. 124.96±4.96, lung MDA (nmol/mg): 5.59±0.24 vs. 7.09±0.39, lung SOD (U/mg): 226.7±3.9 vs. 172.7±3.4, lung phosphorylation of p38MAPK (p-p38MAPK)/p38MAPK: 0.15±0.09 vs. 0.35±0.19, lung phosphorylation of ERK1/2 (p-ERK1/2)/ERK1/2: 0.27±0.01 vs. 0.70±0.01, all P < 0.01]. CONCLUSIONS: HS protected against lung injury induced by severe burns in rats with a dose-dependent manner, and it was better than LR, and its possible mechanism was related with reducing the expression of p38MAPK and ERK1/2 pathway in lung tissue, increasing the level of anti-inflammatory cytokines and decreasing the release of pro-inflammatory cytokines, thus inhibiting excessive inflammation and oxidative stress injury in lung.

[Effect of different concentrations of hypertonic sodium fluid resuscitation on intestine injury in rats at the early stage of severe burn].

OBJECTIVE: To investigate the effect of different concentrations of hypertonic saline solution (HS) on intestine injury in rats at the early stage of severe burn. METHODS: 104 adult healthy female Sprague-Dawley (SD) rats were randomly divided into five groups: sham group (n = 8), lactated Ringer solution (LR) group (n = 24) and 200, 300, 400 mmol/L HS group (HS200 group, HS300 group, HS400 group, all n = 24). All the rats in LR group and different concentrations of HS groups were scalded for 30% total body surface area (TBSA) with III degree, after immediately, the rats were given burn resuscitation therapy by LR or corresponding concentrations of HS through the tail vein. Eight rats were sacrificed on the 2nd, 8th and 24th post-injury hour (PIH), respectively, to collect abdominal aorta blood and intestinal tissues. The rats in sham group were given simulation of burns without resuscitation, which were immediately sacrificed and the specimens were harvested. The serum Na+ concentration was determined by automatic biochemical analyzer. Tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß) contents in serum were determined by enzyme-linked immunosorbent assay (ELISA). The moisture content of intestine reflected by intestine wet/dry weight (W/D) ratio was determined. The content of malondialdehyde (MDA) and the activity of diamine oxidase (DAO) in intestinal tissue were determined by ultraviolet spectrophotometer. The activation of von Willebrand factor (vWF) was assessed by using immunohistochemistry. RESULTS: Compared with sham group, and the contents of TNF-α and IL-1ß in blood and W/D ratio and MDA contents in intestine at each time point after injury in LR group and three HS groups were significantly increased, and the activity of intestinal DAO was significantly decreased. The serum Na+ concentration was significantly reduced in the LR group as compared with that in the sham group, which was significantly higher in the three HS groups than that in the sham group, with the most obvious change on the 8th PIH. Compared with LR group, the serum Na+ concentration and the activity of intestine DAO at each time point after injury in different concentrations of HS groups were significantly increased, and the serum contents of TNF-α, IL-1ß and the W/D ratio, MDA contents in intestine were significantly lowered showing a dose dependent. The changes of HS400 group was the most significantly, and the difference on the 8th PIH was statistically significant as compared with LR group [blood Na+ (mmol/L): 145.51±0.72 vs. 131.52±0.85, intestinal DAO (U/g): 4.85±0.30 vs. 3.50±0.45, blood TNF-α (ng/L): 88.47±4.91 vs. 153.21±13.45, blood IL-1ß (ng/L): 85.77±3.42 vs. 140.57±10.46, intestinal W/D ratio: 3.32±0.05 vs. 3.73±0.09, intestinal MDA (nmol/mg): 0.58±0.01 vs. 0.82±0.04, all P < 0.05]. The immunohistochemical results showed that the vWF activity in the LR group and different concentrations of HS groups was significantly reduced as compared with that of the sham group. Compared with LR group, the activity of intestinal vWF at each time point in different concentration of HS groups was increased to some extent with a dose dependent. The positive staining in HS400 group was the deepest, which showed that the activity of intestinal vWF was the strongest after treated by 400 mmol/L HS. CONCLUSIONS: Compared with LR, HS can attenuate intestinal tissue injury of rats at the early stage of severely burned, and of all, the curative effect of 400 mmol/L HS is the best.

[Effects of three different concentrations of hypertonic sodium salt resuscitation on liver injury of rats at the early stage of severe burned].

OBJECTIVE: To investigate the effects of three different concentrations of hypertonic sodium salt (HS) resuscitation on liver injury of rats at the early stage of severe burned. METHODS: 104 female Sprage-Dawley (SD) rats were randomly divided into five groups: sham group (n = 8), lactated Ringer solution (LR) group (n = 24), 600, 800, 1 000 mmol/L HS groups (HS600, HS800, and HS1000 groups, n = 24). Rats in LR group and HS groups were subjected to full-thickness scald with 30% total body surface area (TBSA), and then given liquid resuscitation treatment with LR and the corresponding HS. These rats were sacrificed at 2, 8 and 24 hours post injury to collect blood and liver tissue. Rats in sham group were given simulation of burns without resuscitation, which were immediately sacrificed and the specimens were harvested. The levels of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were detected by automatic biochemical analyzer. The levels of liver tissue malondialdehyde (MDA) and superoxide dismutase (SOD) were detected by ultraviolet spectrophotometry. The expression of liver tissue p38 mitogen-actirated protein kinase (p38MARK) was detected by Western Blot. RESULTS: Compared with sham group, the levels of ALT, AST, MDA and p38MAPK were increased, and the activities of SOD were decreased in LR group and different degrees in HS groups at each time point after injury. Compared with LR group, the levels of ALT, AST, MDA and p38MAPK were decreased and the activities of SOD were increased in different degrees with HS groups, among which HS600 group changed most significantly [ALT (U/L): 147±52 vs. 227±60 at 8 hours, 138±47 vs. 191±41 at 24 hours; AST (U/L): 288±79 vs. 548±237 at 2 hours, 567±167 vs. 841±338 at 8 hours, 515±180 vs. 712±159 at 24 hours; MDA (nmol/mg): 0.287±0.036 vs. 0.395±0.041 at 2 hours, 0.298±0.030 vs. 0.392±0.018 at 8 hours, 0.278±0.033 vs. 0.422±0.036 at 24 hours; SOD (U/mg): 230±16 vs. 159±30 at 2 hours, 251±14 vs. 194±15 at 8 hours, 296±8 vs. 243±11 at 24 hours; p-p38MAPK/p38MAPK (A value): 0.778±0.040 vs. 1.065±0.066 at 2 hours, 0.791±0.046 vs. 0.967±0.041 at 8 hours, 0.733±0.027 vs. 1.020±0.043 at 24 hours; all P < 0.05]. The levels of ALT and AST in HS600 group were significantly lower than those in HS1000 group at 2 hours and in HS800 group at 8 hours. The levels of MDA and p38MAPK in HS600 group were significantly lower than those of HS800 group and HS1000 group, and the level of SOD in HS600 group was significantly higher than that in HS800 group and HS1000 group at each time point after injury. There were no significant differences in all test indicators between HS800 group and HS1000 group at each time point after injury. CONCLUSIONS: High concentration of HS can reduce the early liver injury in severely scalded rats, of which the curative effect of HS 600 mmol/L is best.