[Short-term effect of gas explosion in real roadway environment on rats' brain neural behavior].

OBJECTIVE: To study the effect of gas explosion on brain nerve behavior of rats in real roadway environment. METHODS: Before the gas explosion, the real gas explosion roadway environment was simulated by using the roadway and explosion test system of gas explosion test in a large coal mine in Chongqing Research Institute of China Coal Science & Technology Group, and cage fixation and explosion parameter setting were carried out. That was to use the equivalent of 9. 0% gas containing mixed air and to install special cage in roadway gas detonation distance at point 40 m, 160 m and 240 m. The SPF grade healthy adult SD male rats anesthetized with chloral hydrate were placed among them, and the rats were placed in a position that could force the head. At the same time, the trunk part below the occipital foramen and the mouth and face above the line of inner canthus were fully protected, and the gas explosion experiment was carried out. A total of 40 rats were randomly divided into four groups according to their body weight: control group, burn-blast combined injuries group(40 m), proximal group(160 m) and distance group(240 m). Ten rats in each group were placed in cages at different distance points under anesthesia except the normal control group. The general physiological behavior of the rats was observed 2 h and 7 d after the explosion, and the neurobehavioral indexes of the rats were monitored by open field behavior experiment. Gross observation and pathological examination of brain tissue were performed 7 days later. RESULTS: The spirits of the rats in the 2 h exposure group after explosion were poor, and improved slightly after 7 d. The degree of surface burn was the most serious in group 40 m. The number of urination decreased while the number of feces increased(P>0. 05). At the end of the experiment, it was found that cerebral edema and hyperemia were obvious in rats. Compared with the normal control group, the brain weight of rats in each exposure group increased, and the difference was statistically significant(P<0. 05). Pathological observation showed that the brain tissues of rats in each exposed group showed irregular and disordered arrangement of nerve cells, interstitial edema, dense and deep staining of loose nuclear chromatin, formation of dense mass and other characteristics of apoptotic cells, as well as increased glia and aggregation of inflammatory cells. At 2 d and 7 h after the explosion, compared with the control group, the resting time of the neurobehavioral indicators of rats at different distance points was significantly prolonged(P<0. 01), while the number of standing times, movement time and movement distance were significantly reduced, and the difference was statistically significant(P<0. 01). CONCLUSION: The gas explosion in real roadway environment can cause certain damage to the brain tissue of rats, and has obvious influence on its neural behavior.

Micelles based on polyvinylpyrrolidone VA64: A potential nanoplatform for the ocular delivery of apocynin.

Purpose of this work was to determine the feasibility of a nano-ophthalmic solution consisting of the nanocarrier polyvinylpyrrolidone VA64 (VA64) and encapsulated apocynin (APO) as treatment for ocular inflammatory diseases. Results showed the solution, termed APO-VA64 ophthalmic solution, could be fabricated via a simple process. This solution was clear, colorless, and possessed valuable characteristics, such as small micelle size (14.12 ± 1.24 nm), narrow micelle size distribution, and high APO encapsulation efficiency. Encapsulated APO was also found to have high aqueous solubility and in vitro release and antioxidant activities. APO-VA64 ophthalmic solution showed good ocular tolerance and demonstrated improved corneal permeation ability in mouse eyes. In an in vivo mice model, topically administered APO-VA64 ophthalmic solution was found to be significantly more effective against benzalkonium chloride-induced ocular damage than APO, VA64, and a mix of APO and VA64. Blockage of high mobility group box 1 signaling and its related proinflammatory cytokines were involved in this therapeutic effect. In conclusion, these in vitro and in vivo findings demonstrate that VA64 micelles are a potential nanoplatform for ocular drug delivery, and that the nanoformulation APO-VA64 ophthalmic solution may be a promising candidate for the efficacious treatment of ocular inflammatory diseases.

Absorption, distribution, metabolism and excretion of the biomaterials used in Nanocarrier drug delivery systems.

Nanocarriers (NCs) are a type of drug delivery system commonly used to regulate the pharmacokinetic and pharmacodynamic properties of drugs. Although a wide variety of NCs has been developed, relatively few have been registered for clinical trials and even fewer are clinically approved. Overt or potential toxicity, indistinct mechanisms of drug release and unsatisfactory pharmacokinetic behavior all contribute to their high failure rate during preclinical and clinical testing. These negative characteristics are not only due to the NCs themselves but also to the materials of the drug nanocarrier system (MDNS) that are released in vivo. In this article, we review the main analytical techniques used for bioassay of NCs and MDNS and their pharmacokinetics after administration by various routes. We anticipate our review will serve to improve the understanding of MDNS pharmacokinetics and facilitate the development of NC drug delivery systems.

Molecular cloning and characterization of wheat calreticulin (CRT) gene involved in drought-stressed responses.

Calreticulin (CRT) is a highly conserved and ubiquitously expressed Ca(2+)-binding protein in multicellular eukaryotes. CRT plays a crucial role in many cellular processes including Ca(2+) storage and release, protein synthesis, and molecular chaperone activity. To elucidate the function of CRTs in plant responses against drought, a main abiotic stress limiting cereal crop production worldwide, a full-length cDNA encoding calreticulin protein namely TaCRT was isolated from wheat (Triticum aestivum L.). The deduced amino acid sequence of TaCRT shares high homology with other plant CRTs. Phylogenetic analysis indicates that TaCRT cDNA clone encodes a wheat CRT3 isoform. Southern analysis suggests that the wheat genome contains three copies of TaCRT. Subcellular locations of TaCRT were the cytoplasm and nucleus, evidenced by transient expression of GFP fused with TaCRT in onion epidermal cells. Enhanced accumulation of TaCRT transcript was observed in wheat seedlings in response to PEG-induced drought stress. To investigate further whether TaCRT is involved in the drought-stress response, transgenic plants were constructed. Compared to the wild-type and GFP-expressing plants, TaCRT-overexpressing tobacco (Nicotiana benthamiana) plants grew better and exhibited less wilt under the drought stress. Moreover, TaCRT-overexpressing plants exhibited enhanced drought resistance to water deficit, as shown by their capacity to maintain higher WUE (water use efficiency), WRA (water retention ability), RWC (relative water content), and lower MDR (membrane damaging ratio) (P < or = 0.01) under water-stress conditions. In conclusion, a cDNA clone encoding wheat CRT was successfully isolated and the results suggest that TaCRT is involved in the plant response to drought stress, indicating a potential in the transgenic improvements of plant water-stress.