Intestinal protein absorption in malnourished mice with acute schistosomiasis mansoni

Intestinal protein absorption was studied in undernourished albino Swiss mice with acute schistosomiasis mansoni. Undernutrition was induced by feeding mice with the Regional Basic Diet (RBD) ingested by human populations in Northeast Brazil, an experimental model previously developed in our laboratory. Weaning mice were infected with 40 cercariae and compared to undernourished non-infected mice and/or to infected mice fed a balanced control diet. Apparent and True Protein Absorption Coefficients were determined by nitrogen balance during five consecutive days ending at the 63rd day of the trial (acute phase of murine schistosomiasis). Fecal metabolic nitrogen (FMN) was determined after administration of a non-protein diet and was also calculated through linear regression. Our results showed a reduced protein absorption in non-infected RBD-fed mice as compared to mice fed a casein control diet. Infection with Schistosoma mansoni had apparently no effect on intestinal protein absorption in well-nourished mice. However, infection seemed to interfere with protein absorption in under-nourished animals, since the lowest absorption ratios have been detected among RBD-fed infected mice. A brief discussion is made on the advantages of using the method of linear regression for the determination of FMN.

Helminth Parasites of Conventionally Maintained Laboratory Mice: II- Inbred Strains with an Adaptation of the Anal Swab Technique

Worm burdens recovered from inbred mice strains, namely C57Bl/6, C57Bl/10, CBA, BALB/c, DBA/2 and C3H/He, conventionally maintained in two institutional animal houses in the State of Rio de Janeiro, RJ, Brazil, were analyzed and compared, regarding their prevalences and mean intensities.Three parasite species were observed: the nematodes Aspiculuris tetraptera, Syphacia obvelata and the cestode Vampirolepis nana. A modification of the anal swab technique is also proposed for the first time as an auxiliary tool for the detection of oxyurid eggs in mice

Studies on the virulence and attenuation of Trypanosoma cruzi using immunodeficient animals

Tissue invasion and pathology by Trypanosoma cruzi result from an interaction between parasite virulence and host immunity. Successive in vivo generations of the parasite select populations with increasing ability to invade the host. Conversely, prolonged in vitro selection of the parasite produces attenuated sublines with low infectivity for mammals. One such subline (TCC clone) has been extensively used in our laboratory as experimental vaccine and tested in comparative experiments with its virulent ancestor (TUL). The experiments here reviewed aimed at the use of immunodeficient mice for testing the infectivity of TCC parasites. It has not been possible to obtain virulent, revertant sublines by prolonged passaged in such mice.

Genes involved in the astrocyte-neuron lactate shuttle (ANLS) are specifically regulated in cortical astrocytes following sleep deprivation in mice.

STUDY OBJECTIVES: There is growing evidence indicating that in order to meet the neuronal energy demands, astrocytes provide lactate as an energy substrate for neurons through a mechanism called "astrocyte-neuron lactate shuttle" (ANLS). Since neuronal activity changes dramatically during vigilance states, we hypothesized that the ANLS may be regulated during the sleep-wake cycle. To test this hypothesis we investigated the expression of genes associated with the ANLS specifically in astrocytes following sleep deprivation. Astrocytes were purified by fluorescence-activated cell sorting from transgenic mice expressing the green fluorescent protein (GFP) under the control of the human astrocytic GFAP-promoter. DESIGN: 6-hour instrumental sleep deprivation (TSD). SETTING: Animal sleep research laboratory. PARTICIPANTS: Young (P23-P27) FVB/N-Tg (GFAP-GFP) 14Mes/J (Tg) mice of both sexes and 7-8 week male Tg and FVB/Nj mice. INTERVENTIONS: Basal sleep recordings and sleep deprivation achieved using a modified cage where animals were gently forced to move. MEASUREMENTS AND RESULTS: Since Tg and FVB/Nj mice displayed a similar sleep-wake pattern, we performed a TSD in young Tg mice. Total RNA was extracted from the GFP-positive and GFP-negative cells sorted from cerebral cortex. Quantitative RT-PCR analysis showed that levels of Glut1, α-2-Na/K pump, Glt1, and Ldha mRNAs were significantly increased following TSD in GFP-positive cells. In GFP-negative cells, a tendency to increase, although not significant, was observed for Ldha, Mct2, and α-3-Na/K pump mRNAs. CONCLUSIONS: This study shows that TSD induces the expression of genes associated with ANLS specifically in astrocytes, underlying the important role of astrocytes in the maintenance of the neuro-metabolic coupling across the sleep-wake cycle.

Constraint and cost of oxidative stress on reproduction: correlative evidence in laboratory mice and review of the literature.

ABSTRACT: BACKGROUND: One central concept in evolutionary ecology is that current and residual reproductive values are negatively linked by the so-called cost of reproduction. Previous studies examining the nature of this cost suggested a possible involvement of oxidative stress resulting from the imbalance between pro- and anti-oxidant processes. Still, data remain conflictory probably because, although oxidative damage increases during reproduction, high systemic levels of oxidative stress might also constrain parental investment in reproduction. Here, we investigated variation in oxidative balance (i.e. oxidative damage and antioxidant defences) over the course of reproduction by comparing female laboratory mice rearing or not pups. RESULTS: A significant increase in oxidative damage over time was only observed in females caring for offspring, whereas antioxidant defences increased over time regardless of reproductive status. Interestingly, oxidative damage measured prior to reproduction was negatively associated with litter size at birth (constraint), whereas damage measured after reproduction was positively related to litter size at weaning (cost). CONCLUSIONS: Globally, our correlative results and the review of literature describing the links between reproduction and oxidative stress underline the importance of timing/dynamics when studying and interpreting oxidative balance in relation to reproduction. Our study highlights the duality (constraint and cost) of oxidative stress in life-history trade-offs, thus supporting the theory that oxidative stress plays a key role in life-history evolution.

Expression of the NH(2)-terminal fragment of RasGAP in pancreatic beta-cells increases their resistance to stresses and protects mice from diabetes.

OBJECTIVE: Our laboratory has previously established in vitro that a caspase-generated RasGAP NH(2)-terminal moiety, called fragment N, potently protects cells, including insulinomas, from apoptotic stress. We aimed to determine whether fragment N can increase the resistance of pancreatic beta-cells in a physiological setting. RESEARCH DESIGN AND METHODS: A mouse line, called rat insulin promoter (RIP)-N, was generated that bears a transgene containing the rat insulin promoter followed by the cDNA-encoding fragment N. The histology, functionality, and resistance to stress of RIP-N islets were then assessed. RESULTS: Pancreatic beta-cells of RIP-N mice express fragment N, activate Akt, and block nuclear factor kappaB activity without affecting islet cell proliferation or the morphology and cellular composition of islets. Intraperitoneal glucose tolerance tests revealed that RIP-N mice control their glycemia similarly as wild-type mice throughout their lifespan. Moreover, islets isolated from RIP-N mice showed normal glucose-induced insulin secretory capacities. They, however, displayed increased resistance to apoptosis induced by a series of stresses including inflammatory cytokines, fatty acids, and hyperglycemia. RIP-N mice were also protected from multiple low-dose streptozotocin-induced diabetes, and this was associated with reduced in vivo beta-cell apoptosis. CONCLUSIONS: Fragment N efficiently increases the overall resistance of beta-cells to noxious stimuli without interfering with the physiological functions of the cells. Fragment N and the pathway it regulates represent, therefore, a potential target for the development of antidiabetes tools.

A laboratory cage for foster nursing newborn mice

We describe a cage to be used for foster nursing in order to guarantee that original mother's colostrum is not ingested by the newborn mice. A common (30.5 cm x 19.5 cm x 12.0 cm) mouse cage was fitted with a wire net tray with a mesh (1 cm x 1 cm), which divides the cage into an upper and a lower compartment. Mice born to females placed in the upper compartment pass through the mesh and fall into the lower compartment, where another lactating female with one or two of its own pups are. Of a total of 28 newborn mice of C3H/He and Swiss strains, 23 were successfully fostered. Important observations are presented to show that this is a valuable alternative for foster studies without great suffering on the part of the female.

Immunomodulatory properties of Alternanthera tenella Colla aqueous extracts in mice

Plants from the genus Alternanthera are thought to possess antimicrobial and antiviral properties. In Brazilian folk medicine, the aqueous extract of A. tenella Colla is used for its anti-inflammatory activity. The present study investigated the immunomodulatory property of A. tenella extract by evaluating the antibody production in male albino Swiss mice weighing 20-25 g (10 per group). The animals received standard laboratory diet and water ad libitum. The effect of A. tenella extract (5 and 50 mg/kg, ip) was evaluated in mice immunized with sheep red blood cells (SRBC 10%, ip) as T-dependent antigen, or in mice stimulated with mitogens (10 µg, Escherichia coli lipopolysaccharide, LPS, ip). The same doses (5 and 50 mg/kg, ip) of A. tenella extract were also tested for antitumor activity, using the Ehrlich ascites carcinoma as model. The results showed that 50 mg/kg A. tenella extract ip significantly enhanced IgM (64%) and IgG2a (50%) antibody production in mice treated with LPS mitogen. The same dose had no effect on IgM-specific response, whereas the 5 mg/kg treatment caused a statiscally significant reduction of anti-SRBC IgM-specific antibodies (82%). The aqueous extract of A. tenella (50 mg/kg) increased the life span (from 16 ± 1 to 25 ± 1 days) and decreased the number of viable tumor cells (59%) in mice with Ehrlich ascites carcinoma. The present findings are significant for the development of alternative, inexpensive and perhaps even safer strategies for cancer treatment.

Transport of animals between rooms: A little-noted aspect of laboratory procedure that may interfere with memory

This study investigated the effects of transporting animals from the experimental room to the animal facility in between experimental sessions, a procedure routinely employed in experimental research, on long-term social recognition memory. By using the intruder-resident paradigm, independent groups of Wistar rats exposed to a 2-h encounter with an adult intruder were transported from the experimental room to the animal facility either 0.5 or 6h after the encounter. The following day, residents were exposed to a second encounter with either the same or a different (unfamiliar) intruder. Resident`s social and non-social behaviors were carefully scored and subjected to Principal Component Analysis, thus allowing to parcel out variance and relatedness among these behaviors. Resident rats transported 6h after the first encounter exhibited reduced amount of social investigation towards familiar intruders, but an increase of social investigation when exposed to a different intruder as compared to the first encounter. These effects revealed a consistent long-lasting (24h) social recognition memory in rats. In contrast, resident rats transported 0.5 h after the first encounter did not exhibit social recognition memory. These results indicate that this common, little-noted, laboratory procedure disturbs long-term social recognition memory. (C) 2011 Elsevier B.V. All rights reserved.

Effect of the bacillus of Calmette-Guerin, Propionibacterium acnes and avridine as immunomodulators in antirabies vaccination of mice using the Fuenzalida-Palacios mouse brain vaccine

Using the laboratory mice, Fuenzalida-Palacios mouse brain human rabies vaccine was administered in groups of animals previously inoculated with rabies virus and then submitted to treatments with the immunomodulators onco-BCG, avridine and Plopionibacterium acnes. Humoral and cellular immune responses were evaluated through the macrophage inhibition factor (MIF), intra-pad inoculation (IPI) and serum neutralization (SN) tests and by the detection of gamma-interferon (IFN-gamma). The IPI test was not effective in detecting the response of delayed-type hypersensitivity, contrary to MIF, which showed the immune cellular response. Higher levels of IFN-gamma were observed in the groups of mice vaccinated and treated with avridine and P. acnes. Although immunomodulating activities have been detected, the use of adjuvants with the Fuenzalida-Palacios type vaccine in mice did not reveal any encouraging results. (C) 1999 Elsevier B.V. Ltd. All rights reserved.

Orchidopexy restores morphometric-stereologic changes in the caput epididymis and daily sperm production in cryptorchidic mice, although sperm transit time and fertility parameters remain impaired

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of canine brain decomposition on laboratory diagnosis of rabies.

Canine brains infected with rabies virus were submitted to decomposition by being left at room temperature of 25 to 29 degrees C for up to 168 h. At 24 h intervals, brain fragments were analyzed by immunofluorescence (IF) and by the mouse intracerebral inoculation (MI) test to confirm the diagnosis of rabies and to measure the putrefaction effect on the accuracy of the diagnosis. Forty eight h after the beginning of the experiment, the MI test showed signs of impairment with four negative results, while after 72 h, 100% of the results were negative to the MI test and only one result was negative to the IF test, indicating that the threshold period for accurate diagnosis is 24 to 48 h before putrefaction. The authors recommend the shipment of suspected cases of rabies to the laboratory for confirmation, but the use of putrid materials for diagnosis is meaningless because of false-negative results.

Poisoning of mice by Baccharis coridifolia: An experimental model

The poisonous plant Baccharis coridifotia causes necrosis in lymphoid tissues and the gastrointestinal tract of cattle, horses, sheep and rabbits. An experimental poisoning of mice was undertaken to establish an experimental model in a laboratory animal specie. A single 5 to 8-g/kg dose of a suspension of the plant was administered by gavage to II mice. To 3 other control mice, the same volume of water was administered. Plant-dosed mice manifested clinical effects after 12 h: tachipnea, trembles, dehydration and prostration. Most of the dosed mice died 14 to 33 h after plant administration-3 survived for 12 d. Six mice had remarkable necrosis of the germinative center of secondary follicles in lymph nodes and spleen; 3 mice had necrosis of lymphoid tissues in intestine and thymus. Mice reproduce most of the lesions observed in naturally poisoned cattle and the use of this specie as an experimental model is valid.

Refining the intestinal motility test in mice to reduce animal stress

A new protocol using 3-h fast animal for intestinal motility test was developed in our laboratory aiming the 3R's concept to reduce the stress of animals. Our results may aid in formulating recommendations that can be included in revised guidelines with regard to fasting time of mice.