[Ruifuping pectin protects against intestinal mucosal injury in the rat exertional heat stroke model].

OBJECTIVE: To evaluate the intestinal function in rats with exertional heat stroke (EHS) and explore the protective role of Ruifuping pectin (RFP) against heat related intestinal mucosal injury. METHODS: One hundred and twenty healthy special pathogen free (SPF) male Sprague-Dawley (SD) rats were randomly divided into normothermic control group, EHS model group, hyperthermic plus drinking water group (H2O+EHS group) and hyperthermic plus pectin group (RFP+EHS group) with 30 rats in each group. The rats in the H2O+EHS group and RFP+EHS group were given water 20 mL/kg or RFP 20 mL/kg orally for 5 days during adaptive training period. After 1 week, the temperature control range was adjusted to (37±1) centigrade using the temperature control treadmill, and the rat model of EHS was reproduced by one-time high temperature exhaustive exercise. No rehydration intervention was given during the training adaptation period in the EHS model group. The rats in the normothermic control group were maintained to room temperature (25±2) centigrade and humidity (55±5)% without other treatment. Behavior tests including withdraw response, righting, and muscle strength were performed immediately after onset of EHS. Blood of inferior vena cava was collected, and the serum inflammatory cytokines [tumor necrosis factor-α (TNF-α) and interleukins (IL-6, IL-1ß, IL-10)] and activity of diamine oxidase (DAO) were detected by enzyme linked immunosorbent assay (ELISA). The intestinal mucosa was collected, after hematoxylin-eosin (HE) staining, and Chiu score was performed to assess EHS induced pathological changes under light microscope. RESULTS: The rats in the EHS model group had behavioral, inflammatory and pathological changes, such as delayed withdraw response and righting, decreased forelimb pulling, increased inflammatory index, and obvious intestinal mucosal injury, which indicated that the reproduction of the EHS model was successful. There was no significant difference in above parameters between the H2O+EHS group and the EHS model group except that the inflammatory index in the RFP+EHS group was improved. Compared with the EHS model group, the withdraw reflex to pain and righting after RFP pretreatment in the RFP+EHS group were significantly improved (righting score: 1.4±0.2 vs. 0.3±0.2, withdraw reflex to pain score: 1.0±0.1 vs. 0.2±0.1, both P < 0.05), the muscle strength was significantly increased (N: 13.0±0.5 vs. 8.2±0.6, P < 0.01). The levels of pro-inflammatory factors in the RFP+EHS group were significantly lower than those in the EHS model group [TNF-α (ng/L): 67.5±9.2 vs. 194.3±13.7, IL-6 (ng/L): 360.0±54.1 vs. 981.2±84.4, IL-1ß (ng/L): 33.7±9.0 vs. 88.7±6.1, all P < 0.01], while the level of anti-inflammatory factor IL-10 was higher than that in the EHS model group (ng/L: 208.7±10.5 vs. 103.7±7.0, P < 0.01). The degree of intestinal mucosal injury in the RFP+EHS group was less severe than that in the EHS model group, and the Chiu score and DAO were significantly lower than those in the EHS model group [Chiu score: 1.5±0.2 vs. 3.8±0.0, DAO (U/L): 83.7±6.7 vs. 128.7±10.5, both P < 0.05]. CONCLUSIONS: High temperature training can damage the intestinal barrier function, and induce endotoxemia and systemic inflammatory response syndrome (SIRS) in rats. Oral prophylactic RFP can protect the intestinal barrier function, alleviate SIRS, and promote the recovery of basic nerve reflex and muscle strength after the occurrence of EHS in rats.

Exonuclease-assisted target recycling amplification for label-free chemiluminescence assay and molecular logic operations.

A versatile exonuclease III (Exo III)-assisted target recycling amplification (Exo-TRA) strategy is demonstrated to achieve label-free and homogeneous chemiluminescence (CL) detection of target DNA. Inspired by this principle, a series of logic gates are constructed using DNA molecules as "inputs" to activate the Exo-TRA system.

Label-free chemiluminescent aptasensor for platelet-derived growth factor detection based on exonuclease-assisted cascade autocatalytic recycling amplification.

Here an exonuclease III (Exo III)-assisted cascade autocatalytic recycling amplification (Exo-CARA) strategy is proposed for label-free chemiluminescent (CL) detection of platelet-derived growth factor BB (PDGF-BB) by taking advantage of both recognition property of aptamer and cleavage function of Exo III. Functionally, this system consists of a duplex DNA (aptamer-blocker hybrid), two kinds of hairpin structures (MB1 and MB2), and Exo III. Upon recognizing and binding with PDGF-BB, aptamer folds into a close configuration, which initiates the proposed Exo-CARA reaction (Recyclings I→II→III→II). Finally, numerous "caged" G-quadruplex sequences on DNAzyme1 and DNAzyme2 release that intercalate hemin to catalyze the oxidation of luminol by H2O2 to generate an amplified CL signal, achieving excellent specificity and high sensitivity with a detection limit of 6.8×10(-13) M PDGF-BB. The proposed strategy has the advantages of simple design, isothermal conditions, homogeneous reaction without separation and washing steps, effective-cost without the need of labeling, and high amplification efficiency, which might be a universal and promising protocol for the detection of a variety of biomolecules whose aptamers undergo similar conformational changes.

Hybridization chain reaction-based branched rolling circle amplification for chemiluminescence detection of DNA methylation.

A novel hybridization chain reaction-based branched rolling circle amplification combining the fabrication of multi-HRP-capped MNPs is developed for chemiluminescence detection of DNA methyltransferase activities and inhibitors with high sensitivity in a well-controlled manner.

A graphene oxide platform for the assay of biomolecules based on chemiluminescence resonance energy transfer.

The bifunctionality of graphene oxide (GO) that can highly adsorb single-stranded DNA (ssDNA) and effectively quench the emission of organic dyes is reasonably utilized in a chemiluminescence resonance energy transfer (CRET) system, achieving sensitive and selective detection of DNA (H1V1) and protein (thrombin), respectively.

[Intervention of nutritional status and hypoxia endurance by a nutritional supplement in young adults living at high altitude].

AIM: To investigate the effects of a nutritional supplement on nutritional status and hypoxia endurance in young adults living at high altitude. METHODS: Forty healthy male young adults were recruited and randomly assigned to control and intervention groups. The nutrition survey was carried out using weighing method. The intervention group was given a nutritional supplement specifically designed for use at high altitude, while the control group was treated with a supplement made of stir-fried flour. After 20 days of supplementation, they marched from the altitude of 3700 m to 5100 m. The changes in HR, SaO2, serum concentrations of VA and VB2 and some minerals were measured. RESULTS: The results of nutrition survey showed that the ratio of three macronutrients was not adequate and the intakes of calcium, VA and VB2 were below Chinese RNI. The serum concentrations of calcium, magnesium and VA were below normal references. The serum VB2 concentration was at the low level o f normal reference. The nutritional supplement could increase the serum concentrations of calcium, magnesium, VA and VB2, indicating an improved nutritional status. The changes in HR and SaO2 were diminished in intervention group compared with control group. CONCLUSION: The nutritional supplement can improve nutritional status and increase the hypoxia endurance in young adults living at high altitude.