Luteolin alleviates vascular dysfunctions in CLP-induced polymicrobial sepsis in mice.

BACKGROUND: Luteolin, a naturally occurring flavonoid, is thought to have health-promoting properties as a part of human diet and has been reported to possess a wide range of pharmacological activities. Therefore, the present study was undertaken to evaluate the effect of luteolin pre-treatment on vascular dysfunctions in sepsis induced by caecal ligation and puncture (CLP) in the mouse model. METHODS: Mice were divided into four groups: sham, luteolin plus sham, CLP, and luteolin plus CLP. Luteolin was administered (0.2 mg/kg body weight) intraperitoneally one hour (h) before CLP surgery in mice. 20 ± 2 h post CLP surgery, the isolated thoracic aorta of mice was assessed for its vascular reactivity to noradrenaline (NA) and acetylcholine (ACh). To explore the underlying mechanism, aortic mRNA expressions of α1D adrenoceptors, eNOS and iNOS were investigated. RESULTS: In mice with CLP-induced sepsis luteolin pre-treatment markedly increased the survival time and attenuated serum lactate level. The CLP group manifested the reduced vascular reactivity to NA and this deficit was restored by luteolin pre-treatment. However, luteolin pre-treatment did not improve α1D adrenoceptors down-regulation observed in septic mice aorta. In the presence of 1400 W, the NA contractile response was significantly restored in CLP mice aortic tissue in comparison with the respective control of septic mice and further enhanced in the presence of luteolin. Luteolin reduced the iNOS mRNA expression and iNOS-derived nitrite production. Pre-treatment with luteolin restored the endothelial dysfunction in septic mice aorta by improving eNOS mRNA expression and enhanced eNOS-derived nitric oxide (NO) production in septic mice aorta and aortic iNOS gene expression and inducible NO production. CONCLUSION: The present study suggests that the vasoplegic state to NA in aorta was restored through the iNOS pathway and endothelial dysfunction was reversed via eNOS and NO production pathway.

Kaempferol-induces vasorelaxation via endothelium-independent pathways in rat isolated pulmonary artery.

BACKGROUND: Kaempferol, a flavonoid, is the essential part of human diet. Flavonoids have different pharmacological activities like cardioprotective, anti-inflammatory and anti-oxidant. The aim of current study was to investigate vasorelaxant potential of kaempferol on rat isolated pulmonary artery and to assess the underling mechanisms. METHODS: Tension experiments were conducted on both the branches of main pulmonary artery of rats. Experiments were done using isolated organ bath system by recording tension with the help of data acquisition system, Power Lab. RESULTS: Kaempferol (10-8-10-4.5M) caused concentration-dependent relaxation (Emax 124.33±4.37%; pD2 5.03±0.084) of endothelium-intact pulmonary artery. In endothelium-denuded arterial rings, relaxation produced by kaempferol was not different from intact artery. L-NAME, indomethacin, combination of L-NAME and indomethacin did not show any effect on kaempferol-induced relaxation. Kaempferol-induced relaxation was reduced (Emax 55.53±7.72%) in 60mMK+ pre-contracted pulmonary arterial rings. Iberiotoxin significantly decreased (Emax 71.68±11.84%) the relaxation response. However, glibenclamide, BaCl2, 4-AP (1mM) and ICI182780 did not reduce the kaempferol-induced relaxation. TEA (10mM) and 4-AP (5mM) significantly reduced relaxation. Kaempferol-induced relaxation was significantly attenuated (Emax 94.92±19.60%) in presence of ODQ. H89 significantly decreased (Emax, 98.38±8.55%) the kaempferol-induced relaxation in rat pulmonary arterial rings. HC067047 and apamin did not show any effect on kaempferol-induced relaxation. In endothelium-denuded K+ (80mM)-depolarized arterial rings, kaempferol (10µM) markedly reduced CaCl2-induced contractions (Emax 35.14±6.53% vs. control 69.04±15.19%). CONCLUSION: Kaempferol relaxes rat pulmonary artery in endothelium-independent manner through involvement of BKCa channel, sGC, PKA pathways and inhibition of Ca2+-influx through L-type calcium channels.

Luteolin attenuates acute lung injury in experimental mouse model of sepsis.

The present investigation was undertaken to assess the result of pretreatment of luteolin in sepsis-induced acute lung injury in mice and its mechanism of action. Luteolin was administered intraperitoneally one hour before caecal ligation and puncture (CLP) surgery in mice. Acute lung injury was assessed by estimation of different parameters like lung edema, protein content, cytokines level, oxidative stress, inducible nitric oxide synthase (iNOS), intercellular adhesion molecule (ICAM)-1 expression and histopathology. Pretreatment of mice with luteolin showed decrease lung edema and protein content in tissue and bronchoalveolar lavage fluid (BALF). However, mice pretreated with luteolin showed reduction (p = 0.92) in blood and lung tissue bacterial counts however it was non significant. Further, luteolin showed significant reduction in interleukin (IL)-6 and IL-1ß in lung tissue which are the proinflammatory cytokines. However, plasma IL-1ß and tissue tumor necrosis factor (TNF)-α level decrease (p = 0.24; p = 0.19) with this pretreatment. Further, ICAM-1 mRNA expression and nuclear factor (NF)-kappa B protein expression were significantly (p < 0.01) decreased in luteolin pretreated septic mice. The lung iNOS level, iNOS mRNA and protein expressions were markedly (p = 0.25; p = 0.50; p = 0.06) altered with luteolin pretreatment, respectively. Also, significant reduction in lipid peroxidation and increase in the activity of antioxidant enzymes like superoxide dismutase (SOD) and catalase was noted with luteolin pretreatment. However, luteolin did not alter (p = 0.36) the non enzymatic antioxidant GSH activity in septic mice. Histopathology of lung tissue showed reduction in lung injury with the luteolin pretreatment in septic mice. The study suggests that luteolin showed attenuation in sepsis-induced acute lung injury in mice through suppression in ICAM-1, NF-kappa B, oxidative stress and partially iNOS pathways.

Kaempferol attenuates acute lung injury in caecal ligation and puncture model of sepsis in mice.

AIM OF THE STUDY: Kaempferol is a flavonoid and important part of the diet. Kaempferol has shown antioxidant, antiinflammatory and antidiabetic activities in various studies. However, protective potential of kaempferol in acute lung injury induced by sepsis and its mechanism remains unclear. The present study was undertaken to evaluate the effect of kaempferol in sepsis-induced acute lung injury in mice and its possible mechanism of action. MATERIALS AND METHODS: Acute lung injury was induced by CLP surgery in mice. Kaempferol (100 mg/kg bw) was administered orally one hour before caecal ligation and puncture surgery in mice. Mice were divided into four groups sham, KEM+sham, sepsis (CLP), and KEM+sepsis. Assessment of lung injury was done by estimation of protein content in lung tissue, lung edema, proinflammatory cytokines in plasma and lung tissue, oxidative stress, antioxidant enzymes, nitrite production, and histopathology. RESULTS: Kaempferol pretreated mice showed significant (P < 0.001) decrease in water content in lungs. Kaempferol pretreatment showed reduction in cytokines IL-6, IL-1ß, and TNF-α in plasma as well as in lung tissue in comparison with septic mice without pretreatment. Pretreatment with kaempferol did not show any reduction in MDA level in comparison with septic mice. Antioxidant enzymes SOD and catalase and nonenzymatic antioxidant GSH activities were also increased with kaempferol pretreatment in septic mice. Further, kaempferol pretreatment reduced the lung tissue nitrite level (P < 0.01) and iNOS (P < 0.05) level in septic mice. A significant (P < 0.01) downregulation of mRNA expression of ICAM-1 and iNOS was observed with this pretreatment. Kaempferol pretreatment did not decrease bacterial load in septic mice. Mice pretreated with kaempferol followed by sepsis showed lesser infiltration of cells and more arranged alveolar structure in histopathological analysis. CONCLUSIONS: The study suggests that kaempferol showed attenuation in sepsis-induced acute lung injury in mice through suppression of oxidative stress, iNOS, and ICAM-1 pathways.

Evaluation of ameliorative potential of supranutritional selenium on enrofloxacin-induced testicular toxicity.

The study was designed to assess the ameliorative potential of selenium (Se) on enrofloxacin-induced testicular toxicity in rats. There was a significant decrease in body weight and non-significant decrease in mean testicular weight of enrofloxacin treated rats. In enrofloxacin treated rats, total sperm count and viability decreased where as sperm abnormalities increased. Testicular histopathology revealed dose dependent dysregulation of spermatogenesis and presence of necrotic debris in seminiferous tubules which was marginally improved with Se. Enrofloxacin also produced a dose dependent decrease in testosterone level. The activity of testicular antioxidant enzymes decreased where as lipid peroxidation increased in a dose-dependent manner. Se supplementation partially restored oxidative stress and sperm damage and did not affect the plasma concentrations of enrofloxacin or ciprofloxacain. The results indicate that enrofloxacin produces a dose-dependent testicular toxicity in rats that is moderately ameliorated with supranutritional Se.