[Effect and mechanism of astaxanthin on acute kidney injury in rats with full-thickness burns].

Objective: To explore the effect and mechanism of astaxanthin on acute kidney injury in rats with full-thickness burns. Methods: Forty-eight male Sprague Dawley rats of 8 to 10 weeks were divided into sham injury group, simple burn group, burn+ vehicle group, burn+ low-dose astaxanthin group, burn+ medium-dose astaxanthin group, and burn+ high-dose astaxanthin group according to the random number table, with 8 rats in each group. The back skin of rats in sham injury group were immersed in warm water of 20 ℃ for 15 s to simulate burn injury, and the back skin of rats in the other 5 groups were immersed in boiled water of 100 ℃ for 15 s to inflict full-thickness burn of 30% total body surface area. Fluid resuscitation was performed in rats in the 5 groups except of sham injury group immediately and 6 h after injury. At 30 min after injury, the rats in sham injury group and simple burn group were injected with 1 mL/kg normal saline via tail vein, rats in burn+ vehicle group were injected with 1 mL/kg astaxanthin solvent via tail vein, and rats in burn+ low-dose astaxanthin group, burn+ medium-dose astaxanthin group, and burn+ high-dose astaxanthin group were respectively injected with 5, 10, 20 mg/kg astaxanthin solution of 5, 10, 20 mg/mL via tail vein. The renal tissue was collected at post injury hour (PIH) 48, and hematoxylin eosin staining was used for histopathological observation and renal tubular injury score. At PIH 48, the venous blood was collected for detecting serum creatinine level through blood biochemical analyzer, and blood urea nitrogen (BUN) level was detected by enzyme-linked immunosorbent assay. The renal tissue was collected to detect the mRNA expressions of myeloperoxidase (MPO), interleukin-1ß (IL-1ß), and IL-6 by real-time fluorescent quantitative reverse transcription polymerase chain reaction method, and the protein expressions of Toll like receptor 4 (TLR4), phosphorylated nuclear factor kappa B (p-NF-кB) p65, and heme oxygenase 1 (HO-1) were detected by Western blotting. Besides, the expression of HO-1 in renal tissue was detected by immunofluorescence method. Data were statistically analyzed with Kruskal-Wallis H test, Dunn-Sidák correction, one-way analysis of variance, and Bonferroni method. Results: (1) At PIH 48, there were no inflammatory cell infiltrating and degeneration or necrosis of cells in renal tissue of rats in sham injury group, and the structure of renal tubules was intact. The renal tubules of burn rats in each group showed injury manifestation of separation between epithelial cell and basement membrane, and vacuole cells and lysate protein aggregation. The injury degree of renal tissue of rats in burn+ high-dose astaxanthin group was obviously decreased compared with that in simple burn group. (2) At PIH 48, compared with that of sham injury group, the renal tubular damage scores of rats in simple burn group, burn+ vehicle group, burn+ low-dose astaxanthin group, and burn+ medium-dose astaxanthin group were significantly increased (P<0.05 or P<0.01). Compared with those of simple burn group and burn+ vehicle group, the renal tubular damage scores of rats in burn+ medium-dose astaxanthin group and burn+ high-dose astaxanthin group were significantly decreased (P<0.05 or P<0.01). Compared with that of burn+ low-dose astaxanthin group, the renal tubular damage score of rats in burn+ high-dose astaxanthin group was significantly decreased (P<0.01). (3) At PIH 48, the level of serum creatinine of rats in sham injury group was (2.42±0.06) mg/L, which was significantly lower than (6.11±0.11), (6.48±0.08), (5.79±0.09), (4.03±0.12) mg/L of simple burn group, burn+ vehicle group, burn+ low-dose astaxanthin group, and burn+ medium-dose astaxanthin group (P<0.05 or P<0.01). The level of BUN of rats was (21.9±1.3) mmol/L in sham injury group, significantly lower than (32.1±7.4) mmol/L of simple burn group and (30.2±4.8) mmol/L of burn+ vehicle group (P<0.05 or P<0.01). At PIH 48, compared with those of simple burn group and burn+ vehicle group, the levels of serum creatinine and BUN of (16.0±2.9) mmol/L in burn+ medium-dose astaxanthin group, serum creatinine of (3.02±0.08) mg/L and BUN of (14.5±2.9) mmol/L in burn+ high-dose astaxanthin group, and serum creatinine of (22.8±5.5) mmol/L of rats in burn+ low-dose astaxanthin group were significantly decreased (P<0.05 or P<0.01). At PIH 48, compared with those of burn+ low-dose astaxanthin group, the levels of serum creatinine and BUN of burn+ high-dose astaxanthin group and serum creatinine of burn+ medium-dose group were obviously decreased (P<0.05 or P< 0.01). (4) At PIH 48, compared with those of sham injury group, the mRNA expressions of MPO, IL-1ß, and IL-6 in renal tissue of rats in simple burn group, burn+ vehicle group, burn+ low-dose astaxanthin group, and burn+ medium dose astaxanthin group, and the mRNA expressions of IL-1ß and IL-6 in renal tissue of rats in burn+ high-dose astaxanthin group were obviously increased (P<0.01). Compared with those of simple burn group and burn+ vehicle group, the mRNA expressions of MPO, IL-1ß, and IL-6 in renal tissue of rats were significantly decreased in burn+ low-dose astaxanthin group, burn+ medium-dose astaxanthin group, and burn+ high-dose astaxanthin group (P<0.01). Compared with those of burn+ low-dose astaxanthin group, the mRNA expressions of MPO, IL-1ß, and IL-6 in renal tissue of rats were significantly decreased in burn+ medium-dose astaxanthin group and burn+ high-dose astaxanthin group (P<0.01). The mRNA expressions of MPO, IL-1ß, and IL-6 in renal tissue of rats in burn+ high-dose astaxanthin group were significantly decreased compared with those of burn+ medium-dose astaxanthin group (P<0.01). (5) At PIH 48 h, compared with those of sham injury group, the protein expressions of TLR4 and p-NF-кB p65 in renal tissue of rats in simple burn group, burn+ vehicle group, burn+ low-dose astaxanthin group, and burn+ high-dose astaxanthin group were obviously increased (P<0.01). Compared with those of simple burn group, the protein expressions of TLR4 and p-NF-кB p65 in renal tissue of rats in burn+ low-dose astaxanthin group, burn+ medium dose astaxanthin group, and burn+ high-dose astaxanthin group were significantly decreased (P<0.01). (6) The results of Western blotting combined with immunofluorescence method showed that compared with that of sham injury group, the protein expression of HO-1 in renal tissue of rats in burn+ vehicle group, burn+ low-dose astaxanthin group, burn+ medium-dose astaxanthin group, and burn+ high-dose astaxanthin group were significantly increased at PIH 48 (P<0.01), and the protein expression of HO-1 in renal tissue of rats in burn+ medium-dose astaxanthin group and burn+ high-dose astaxanthin group was significantly increased compared with that of simple burn group (P<0.01). Conclusions: Astaxanthin can attenuate the structural damage and functional decline of renal tissue and regulate the release of injury-related inflammatory factors, thus to protect the rats from acute kidney injury after burn. The HO-1/TLR4/NF-кB signaling pathway is the main regulatory mechanism of astaxanthin to achieve anti-inflammation-based renoprotection.

[Studies on polysaccharides in different development stages of Armillaria mellea (Vahl.: Fr.) Quel].

OBJECTIVE: To study the polysaccharides in different development stages of Armillaria mellea. METHOD: Polysaccharides in rhizomorph, fruit-body, mycelia and its fermenting liquor of A. mellea were extracted, isolated and purified. The properties contents, molar ratio and molecular weight of the polysaccharides were determined by IR spectra, HPLC, GPC and gel chromatography. RESULT: The polysaccharides in mycelia and its fermenting liquor contained only glucose, the sugar contents were 9.00% in mycelia and 0.87 g.(100 ml)-1 in fermenting liquor respectively. The polysaccharides in both rhizomorph and fruit-body consisted of glucose and xylose, and the molar ratio was 1:14 in rhizomorph and 1:10 in fruit-body respectively; the polysaccharide contents were 1.12% in rhizomorph and 2.27% in fruit-body. The molecular weight of these polysaccharides was about 10,000-70,000. CONCLUSION: The experimental results supply important scientific data for developing A. mellea as a medicine.

[Secondary metabolites of Gliocladium sp., a growth accelerating fungus for Anoectochilus roxburghii (Wall.) Lindl].

OBJECTIVE: To study the secondary metabolites of fungus Gliocladium sp. that helps accelerate the growth of A. roxburghii. METHOD: Compoud isolation by chromatography and structure elucidation by chemical and spectral analyses. RESULTS: Five compounds were obtained and elucidated as: 8(E)-N-(2'-hydroxypalmityl)-1-O-beta-gly-copyranosyl-3-hydroxyl-9-methyl-2- octodecanine-4, 8-diene (I), N-(2'-hydroxytetracosanoyl)-1,3,4-trihydroxy-2-octodecanine(II), 7, 22-diene-3-hydroxy-6,9-epidioxyergosta(III), ergostol(IV) and alpha-palmitin(V). CONCLUSION: I, II, III were obtained from Gliocladium sp. for the first time.

[Isolation and biological activity of mycorrhizal fungi from Dendrobium candidum and D. nobile].

OBJECTIVE: To isolate the mycorrhizal fungi from the roots of wild Dendribium candidum and D. nobile collected from Yunnan and Sichuan provinces and determine their biological activities. METHOD: The isolation was completed using solidified potato dextrose agar (PDA, Difco) of plates and the biological activities were tested by means of symbiotic germination of fungus-seedlings. RESULTS: 25 Species of mycorrhizal fungi were obtained and most of them belong to Basidiomycotina and Deuteromycotina. The preliminary biological activity test has shown that of these fungi 5 species help promote the seed germination of D. candidun, 7 species can establish the symbiotical relationship with seedlings of D. candium and D. nobile, and 3 species can stimulate the growth of seedlings of the two medicinal plants. CONCLUSION: Isolation and screening of fungi helpful to the growth and development of Dendrobium is important in the production of the herb.

[Establishment of symbiotic system for Anoectochilus roxburghii (Wall.) Lindl. and endophytic fungi].

OBJECTIVE: Setting up a symbiotic system for Anoectochilus roxburghii and endophytic fungi, so as to study the relationship between them and try to set up new cultural methods for A. roxburghii. METHOD: A. roxburghii and its endophytic fungi were cultured together on five kinds of media in flasks. The growth of the plantlets and fungi were observed. Symbiotic conditions were selected according to symbiotic characteristics. RESULTS: A symbiotic system for A. roxburghii and endophytic fungi was set up. The optimum composition of the system induded NH4NO3 825 mg.L-1, KNO3 950 mg.L-1, MgSO4 185 mg.L-1, and inositol 100 mg.L-1, other organic components being 2/3 times those of MS medium, sugrose 15 g.L-1, and other components being the same as those of MS medium, agar 9 g.L-1, pH 5.8. The culture was effected at 24-25 degrees C under cool white fluorescent light (150 lx) for a photoperiod of 11 hours. CONCLUSION: A. roxburghii and endophytic fungi can grow well together and form endomycorrhiza in the symbiotic system. Moreover, endophytic fungi help stimulate the growth and development of A. roxburghii.

Increased cerebral free radical production during thiamine deficiency.

Concentration of reactive oxygen species (ROS) and the antioxidant glutathione (GSH) was measured in thalamus and cortex after 13 and 14 days of pyrithiamine-induced thiamine deficiency (PTD) in the rat. The concentration of ROS was significantly elevated in thalamus and cortex on day 14 when righting reflexes were absent and spontaneous seizures occurred. No significant changes in GSH concentration were observed in thalamus or cortex on either day of treatment. These findings suggest that increased formation of free radicals occurs during the more acute symptomatic stage of thiamine deficiency and may contribute to the structural damage described in this model of Wernicke's encephalopathy.