Wistar Rats

Non-invasive vaccine delivery is a top priority for public health agencies because conventional immunization practices are unsafe and associated with numerous limitations. Recently, the skin has emerged as a potential alternative route for non-invasive delivery of vaccine. Topical immunization (TI), introduction of antigen through topical application onto the intact skin, has many practical merits compared to injectable routes of administration. One of the possibilities for increasing the penetration of bioactives through the skin is the use of vesicular systems. Specially designed lipid vesicles are attracting intense attention and can be used for non-invasive antigen delivery. In the present study, elastic vesicle transfersomes, non-ionic surfactant vesicles (niosomes) and liposomes were used to study their relative potential in non-invasive delivery of tetanus toxoid (TT). Transfersomes, niosomes and liposomes were prepared and characterized for shape, size and entrapment efficiency. These vesicles were extruded through polycarbonate filter (50-nm pore size) to assess the elasticity of the vesicles. The immune stimulating activity of transfersomes, niosomes and liposomes were studied by measuring the serum anti-TT IgG titre following topical immunization. The immune response elicited by topical immunization was compared with that elicited by same dose of alum-adsorbed tetanus toxoid (AATT) given intramuscularly. The results indicate that optimal formulations of transfersomes, niosomes and liposomes could entrap 72.7 ± 3.4, 42.5 ± 2.4 and 41.3 ± 2.2% of antigen and their elasticity values were 124.4 ± 4.2, 29.3 ± 2.4 and 21.7 ± 1.9, respectively. In vivo study revealed that topically given TT containing transfersomes, after secondary immunization, could elicit immune response (anti-TT-IgG) that was equivalent to one that produced following intramuscularly alum-adsorbed TT-based immunization. In comparison to transfersomes, niosomes and liposomes elicited weaker immune response. Thus transfersomes hold promise for effective non-invasive topical delivery of antigen(s).

Our aim was to study histopathological changes in lung tissue at the light microscopic and ultrastructural level during recovery from immunosuppression and Pneumocystis carinii pneumonia. Male Wistar rats were immunosuppressed by per oral dexamethasone for 12 weeks to induce P. carinii pneumonia, after which dexamethasone was stopped. Recovery was monitored 1, 2 and 4 weeks after cessation of the immunosuppression. In immunosuppressed animals, CD4+ and CD8+ lymphocytes were both decreased in situ. CD8+ lymphocytes increased above control level at week one. Like CD8+ cells, the ED1+ macrophages increased rapidly in situ. This was accompanied by a progressively increasing migration (more transient for lymphocytes) of macrophages into bronchoalveolar fluid, associated with morphological signs of activation and phagocytosis and proliferation of type II pneumocytes. Bronchoalveolar lavage (BAL) fluid tumour necrosis factor-alpha (TNF-alpha) increased from subnormal levels to a 4 week pea...

The pharmacodynamics and pharmacokinetics of bupivacaine in solution and in liposome preparations following subcutaneous administration were studied in rats. Multilamellar vesicles entrapping bupivacaine solution were prepared. The local anaesthetic effect was estimated by the tail-flick test in Wistar rats treated with 1 mg bupivacaine in 0.2-ml. preparations. Plasma concentrations of bupivacaine were determined by high-performance liquid chromatography. The results showed that both bupivacaine solution and bupivacaine liposomes revealed local anaesthetic effects in the initial tail-flick test (15 min after injection). With bupivacaine liposomes, the duration of action was 5-fold (447 ± 28.9 vs 87 ± 6.7 min), the maximum possible effect was 2-fold (100 ± 0 vs 47.6 ± 13%), and the peak plasma concentration (Cmax) was less than one-fifth (0.12 ± 0.04 vs 0.65 ± 0.04 μg mL−1) that with bupivacaine solution. The sensory block effect of bupivacaine solution completely resolved at 90 min,...

The majority of reduced calorie fats and fat substitutes avaiable, today, though similar in texture and flavor to natural fats, contain fatty acids that are not usually present in edible oils and fats and thus do not fully match the chemistry and functions of natural fats. For example, such products do not provide nutritionally important essential fatty acids (EFA). In this investigation, we prepared and evaluated a reduced calorie fat, prepared entirely from natural fats, taking advantage of the fact that long-chain saturated fatty acids (LCSFA), such as behenic acid (22∶0), are poorly absorbed. Mustard oil (MO) and sunflower oil (SO) were used as substrates to yield a structured lipid (SL). The product, being derived from a natural vegetable oil, would thus provide EFA, as would a native fat, a feature not provided by the low-calorie fats available in the market. Erucic acid (22∶1) was isolated from MO by a lipase (EC 3.1.1.3)-catalyzed reaction. It was then hydrogenated to behenic acid, the ethyl ester of which was subsequently enzymatically transesterified with SO to yield a plastic fat containing about 30–35% behenic acid. Absorption of this fat was studied in Wistar rats. In a preliminary single oral dose experiment, rats were fed equal amounts (2 mL) of SO and the SL. Plasma triacylglycerol (TAG) levels were estimated after 1, 2, and 3 h of feeding. The significantly lower concentration of plasma TAG in the 2-h sample, observed in the SL-fed group compared to the SO-fed group (Pad libitum group the previous day. Body weights were recorded during the experiment. Calorific value of the SL was estimated by comparing the 21st-d mean body weight gain of the control group with that of the experimental group. Estimated calorific value of the SL was 5.36 kcal/g. Most of the behenic acid fed was excreted, as indicated by the analysis of the fatty acids of plasma and fecal total lipid. A second growth experiment on ad libitum diet was conducted over 21 d on weanling Wistar male rats to compare the absorption behavior of the SL with that of natural oil. SO (10%) was added to the diet of the control group, and SL (10%) was added to the diet of the experimental group. Feed consumption, as well as body weights, was recorded during the experiment. The growth pattern of the experimental group was identical to that of the control group during the period of study. The mean feed intake (9.8 g/d/rat for the control group vs. 9.9 g/d/rat for the experimental group) indicated good palatability of the product. In conclusion, the enzymatically synthesized SL containing EFA and natural antioxidants has nutritional properties almost identical to those of natural fats, and can be used as a reduced calorie fat.

The ethanol extract of the bark of Cinnamomum zeylanicum was evaluated for wound healing activity in Wistar rats. The extract was administered by the oral route at a dose of 250 mg/kg and 500 mg/kg body weight (1/8 and 1/4 of LD50, respectively) for all the wound models selected, excision, incision and dead space wounds. The extract significantly enhanced the wound breaking strength in the case of incision wound, the rate of wound contraction and the period of epithelization in the case of excision wound. The granulation tissue weight, its breaking strength and its hydroxyproline content was also increased by the extract in the dead space wound. Copyright © 2003 John Wiley & Sons, Ltd.

Transient receptor potential channels (TRPC) are plasma membrane, non-selective cationic channels and have been proposed as candidates involved in the regulation of cellular Ca2+ influx. TRPC are involved in metabotropic glutamate receptor (mGluR)-mediated excitatory post-synaptic currents (EPSCs) in the dopaminergic neurons of the substantia nigra. We previously observed several subtypes of TRPC to be expressed at an mRNA level in