ABSTRACT
Objective: To explore the factors affecting the nasal entry of the pharmaceutical preparations into the brain based on the established model of the "nose-brain" pathway in vitro. Methods: Calu-3 cells and OECs cells were co-cultured to construct a "nasal-brain" pathway cell model group. Taking fluorescein isothiocyanate dextran (FD) and fluorescent silver nanoparticles (AgNPs) as model drugs, the effects of drug molecular weight (Mw) factors and preparation particle size factors on the drug transnasal transport into the brain were explored. Results: The apparent permeability coefficient (Papp) of transcellular monolayer transport of FD decreased with the increase of molecular weight. The uptake of fluorescein isothiocyanate dextran with different molecular weights by OECs tended to be saturated after 90 min. As the molecular weight of FD increased, the uptake of OECs decreased significantly during the same uptake time. The apparent permeability coefficient of fluorescent AgNPs with different particle sizes in the "nose-brain" multi-channel cell model group of calu-3 monolayer decreased with the increase of the particle size of the nanoparticles. When the particle size was less than 40 nm, its transport characteristics in Calu-3 were shown as medium absorption (1 × 10-6 < Papp < 10 × 10-6), and when the particle size of nanoparticles was more than 60 nm, its transport characteristics were shown as difficult to absorb (Papp < 1 × 10-6). The uptake of OECs of fluorescent AgNPs with different particle sizes tended to be saturated at 60 min, and with the increase of the particle size of fluorescent AgNPs, the uptake of OECs at the same uptake time showed a significant decline. Conclusions The Mw of the drug and the particle size of the nano-formulation have an important influence on the nasal transport of the drug into the brain. Drugs with a molecular weight of < 4 000 and nano particles with a particle size of less than 40 nm have better transport and uptake characteristics.
ABSTRACT
Objective To investigate the protective effect of allicin on intestinal mucosal barrier of septic rats so as to explore the possible mechanism.Methods Twenty-four male SD rats were randomly (random number) divided into sham,septic model and allicin treatment group.Septic model was established by cecal ligation and puncture (CLP) in rats.Rats in the treatment group were administered with allicin (30 mg/kg,ip)at 6 h and 12 h after modeling,while those in the model and sham groups were treated with equal amount of saline instead.Rats were sacrificed at 24 h and the serum D-lactic acid,diamine oxidase (DAO) and fluorescence isothiocyanate-dextran (FITC-Dextran,FD-40) were determined to evaluate the intestinal mucosal barrier function.The levels of tumor necrosis factor-α (TNF-α),interleukin-6 (IL-6),malondialdehyde (MDA),and the activity of superoxide dismutase (SOD) in intestinal tissue were measured.Histopathological changes of intestinal mucosa injury were assessed by Hematoxylin-eosin staining.Results Compared with the sham group,levels of serum D-lactic acid,DAO and FD-40 increased significantly in the CLP group (D-lactic acid:599.4±101.1 vs.149.2±20.63 nmoL/mL,t=11.84,P＜0.01;DAO:302.1 ±64.5 vs.76.57±14.76 ng/mL,t=9.433,P＜0.01;FD-40:6664.0±1437.0vs.1446.0±205.0 ng/mL,t =9.704,P ＜0.01);intestinal morphology damage occurred in the CLP group;intestinal levels of TNF-α,IL-6 and MDA increased greatly (TNF-αt:186.35 ±20.43 vs.58.76 ±8.94 pg/mL,t=17.23,P＜0.01;IL-6:763.25±85.23vs.125.36±14.37 pg/mL,t=22.54,P＜0.01;MDA:29.36±3.27vs.7.24±0.85 nmol/mg prot,t=16.61,P＜0.01),while SOD activity reduced (35.75±6.53 vs.73.26 ±8.35 U/rmg prot,t =10.57,P ＜0.01) in the CLP group.Allicin treatment greatly inhibited the increase of D-lactic acid,DAO and FD-40 levels in rat plasma caused by CLP (D-lactic acid:330.1 ±81.77 vs.599.4±101.1 nmol/mL,t=7.086,P＜0.01;DAO:171.8±49.70vs.302.1±64.56ng/mL,t=5.45,P＜0.01;FD-40:3349.0±1167.0 vs.6664.0±1437.0 ng/mL,t=6.165,P＜0.01);intestinal morphology damage was improved in the allicin treatment group;allicin treatment greatly inhibited the intestinal levels of TNF-o,IL-6 and MDA and preserved the intestinal SOD activity compared with the CLP group (TNF-α:95.37 ±12.68 vs.186.35 ±20.43 pg/mL,t =12.29,P＜0.01;IL-6:354.27±46.27vs.763.25±85.23pg/mL,t=14.45,P＜0.01;MDA:16.27±3.14vs.29.36±3.27 nmol/mgprot,t=9.831,P＜0.01;SOD:55.35 ±6.23vs.35.75±6.53 U/mgprot,t=5.522,P ＜0.01).Conclusions Allicin could inhibit local inflammation and oxidative stress in the intestine and exerts protective effect on intestinal mucosal barrier of septic rats.
ABSTRACT
Background The incidence of retinal vascular diseases increase annually,such as diabetic retinopathy,retinopathy of prematurity and age-related macular degeneration.The key of treatment for these diseases is how to evaluate retinal vascular change effectively and objectively.Retro-orbital injection of fluorescein isothiocyanatedextran (FITC-dextran) is a simple and effective method for observing C57BL/6J mouse retinal vessels.But,whether it is suitable for other mice and rats is seldom reported.Objective This experiment was to assess the feasibility of the observation of retinal vessels by retro-orbital injection of FITC-dextran in different genus of mouse and offer the reference for relevant study.Methods Twelve animals of C57BL/6J mice,Kunming mice,SD rats and Wistar rats were selected,respectively and divided into the experimental group and control group at average.The right eyes of the animals of the experimental group received the retro-orbital injection of 9 ml/kg FITC-dextran,and the right eyes of animals of the control group received PBS solution at the same volume and way.All the animals were sacrificed 10 seconds after injection and both eyes of each animal were obtained for retinal stretched preparation.The retrobulbar tissue and whole-mount retina were viewed under a fluorescence microscope.The use of the animals complied with Regulation for the Administration of Affair Concerning Experimental Animals by State Science and Technology Commission.Results Retinal blood vessels labeled by FITC-dextran could be observed in both eyes of C57BL/6J mice and Kunming mice to present with a green fluorescence in experimental group under a fluorescence microscope,but no any fluorescence-labeled retinal blood vessel was exhibited in the control mice.The retinal blood vessel could not be observed in all eyes of SD rats and Wistar rats after the injection of FITC-dextran both in the experimental group and the control group under a fluorescence microscope.The surrounding tissues of the right eyes of mice and rats dyed with green fluorescence of FITC-dextran in the experimental group,however,green fluorescence could not be seen in the surrounding tissues of the left eyes of mice and rats.Conclusions Retro-orbital injection of FITC-dextran is a suitable method of observing the retinal vessels of mouse but not rat.