Quantification of superoxide radical production in 4 vital organs of rats subjected to hemorrhagic shock

Detection of superoxide radical in all biological systems by Thin Layer Chromatography

The study presents a new method that detects O₂^•-, via quantification of 2-hydroxyethidium (2-ΟΗ-Ε⁺) as low as ∼30 fmoles by High-Performance Thin Layer Chromatography (HPTLC). The method isolates 2-ΟΗ-Ε⁺ after its extraction by the anionic detergent SDS (at 18-fold higher than its CMC) together with certain organic/inorganic reagents, and its HPTLC-separation from di-ethidium (di-Ε⁺) and ethidium (Ε⁺). Quantification of 2-OH-E⁺ is based on its ex/em maxima at 290/540 nm, and of di-E⁺ and E⁺ at 295/545 nm. The major innovations of the present method are the development of protocols for (i) efficient extraction (by SDS) and (ii) sensitive quantification (by HPTLC) for 2-OH-E⁺ (as well as di-E⁺ and E⁺) from most biological systems (animals, plants, cells, subcellular compartments, fluids). The method extracts 2-ΟΗ-Ε⁺ (by neutralizing the strong binding between its quaternary N⁺ and negatively charged sites on phospholipids, DNA etc) together with free HE, while protects both from biological oxidases, and also extracts/quantifies total proteins (hydrophilic and hydrophobic) for expressing O₂^•- levels per protein quantity. The method also uses SDS (at 80-fold lower than its CMC) to extract/remove/wash 2-ΟΗ-Ε⁺ from cell/organelle exterior membrane sites, for more accurate internal content quantification. The new method is applied on indicative biological systems: (1) artificially stressed (mouse organs and liver mitochondria and nuclei, ±exposed to paraquat, a known O₂^•- generator), and (2) physiologically stressed (cauliflower plant, exposed to light/dark).

Kaempferol pretreatment modulates systemic inflammation and oxidative stress following hemorrhagic shock in mice

Background

Kaempferol has been reported as beneficial for both acute and chronic inflammatory diseases. This study aims to investigate whether kaempferol affects systemic inflammation and oxidative stress in the heart, lung, and liver after hemorrhagic shock in mice.

Methods

Male C57/BL6 mice underwent hemorrhagic shock (mean arterial pressure of 35 mmHg for 90 min) and were arbitrarily divided into Sham, hemorrhagic shock (HS), and Kae groups (n = 10 in each group). Mice in the Kae groups received a kaempferol (10-mg/kg body weight) injection 12 h prior to (Group Kae PT) or 90 min after (Group Kae T) the initiation of hemorrhagic shock. Plasma proinflammatory cytokines (TNF-α and IL-6), organ myeloperoxidase (MPO) and superoxide dismutase (SOD) activities, and organ malondialdehyde (MDA) concentrations and heme oxygenase-1 (HO-1) expression levels were assessed by enzyme-linked immunosorbent assay (ELISA) or western blot assay.

Results

Compared with the HS group and the Kae T group, pretreatment with kaempferol significantly decreased proinflammatory cytokines TNF-α (P = 0.012 and 0.015, respectively) and IL-6 (P = 0.023 and 0.014, respectively) following hemorrhagic shock. Kae pretreatment reverted MPO, SOD, and MDA to basal levels in the heart, lung, and liver (Ps < 0.05), while the Kae T group showed no significant differences in these biomarkers compared with the HS group (Ps > 0.05). HO-1 expression was significantly increased in the Kae PT group compared with the other groups (P = 0.011 vs. HS group and P = 0.02 vs. Kae T group).

Conclusions

Pretreatment of hemorrhagic shock mice with kaempferol significantly decreased plasma levels of TNF-α and IL-6; reverted MPO, SOD, and MDA in the heart, lung, and liver; and increased expression of HO-1 in the same organs.

Clonidine pre-treatment prevents hemorrhagic shock-induced endotoxemia and oxidative stress in the gut, liver, and lungs of the rat

OBJECTIVES

To study the effect of clonidine pre-treatment on hemorrhagic shock (H/S)-induced endotoxemia and oxidative stress (OS) in three vital organs of the rat.

METHODS

The study protocol consisted of two arms: one for the measurement of organic hydroperoxide (LOOH) and superoxide radical (O(2)(-·)) production in the gut, liver, and lungs (n = 32 rats) and one for the measurement of endotoxin in portal and systemic circulation (n = 32 rats). Four animal groups (sham, clonidine, H/S, and clonidine-H/S group) were used in each arm. Three hours after H/S and concominant blood resuscitation, tissues were collected for LOOHs and O(2)(-·) measurement and blood samples were obtained for endotoxin determination.

RESULTS

Clonidine pre-treatment prior to H/S resulted in a significant reduction of LOOHs and O(2)(-·) production in all vital organs (P < 0.05-0.001), while additionally, clonidine reduced H/S-induced endotoxemia in portal (P < 0.05) and systemic circulation as well (P < 0.01).

DISCUSSION

Clonidine pre-treatment prevents endotoxemia and OS in the gut, liver, and lungs of rats subjected to severe H/S. The improved intestinal barrier function probably stems from the antioxidant effect of clonidine on the intestinal epithelium, whereas the reduced endotoxemia may contribute to a decreased OS observed in the liver and lungs.