Characterization of the Hippocampal Neuroimmune Response to Binge-Like Ethanol Consumption in the Drinking in the Dark Model.

OBJECTIVES: Alcohol dependence leads to dysregulation of the neuroimmune system, but the effects of excessive alcohol consumption on key players of the neuroimmune response after episodic binge drinking in nondependence has not been readily assessed. These studies seek to determine how the neuroimmune system within the hippocampus responds to binge-like consumption prior to dependence or evidence of brain damage. METHODS: C57BL/6J mice underwent the drinking in the dark (DID) paradigm to recapitulate binge consumption. Immunohistochemical techniques were employed to determine the effects of ethanol on cytokine and astrocyte responses within the hippocampus. Astrocyte activation was also assessed using qRT-PCR. RESULTS: Our results indicated that binge-like ethanol consumption resulted in a 3.6-fold increase in the proinflammatory cytokine interleukin (IL)-1ß immunoreactivity in various regions of the hippocampus. The opposite effect was seen in the anti-inflammatory cytokine IL-10. Binge-like consumption resulted in a 67% decrease in IL-10 immunoreactivity but had no effect on IL-4 or IL-6 compared with the water-drinking control group. Moreover, astrocyte activation occurred following ethanol exposure as GFAP immunoreactivity was increased over 120% in mice that experienced 3 cycles of ethanol binges. PCR analyses indicated that the mRNA increased by almost 4-fold after one cycle of DID, but this effect did not persist in abstinence. CONCLUSIONS: Altogether, these findings suggest that binge-like ethanol drinking prior to dependence causes dysregulation to the neuroimmune system. This altered neuroimmune state may have an impact on behavior but could also result in a heightened neuroimmune response that is exacerbated from further ethanol exposure or other immune-modulating events.

Distinct and Overlapping Patterns of Acute Ethanol-Induced C-Fos Activation in Two Inbred Replicate Lines of Mice Selected for Drinking to High Blood Ethanol Concentrations.

The inbred high drinking in the dark (iHDID1 and iHDID2) strains are two replicate lines bred from the parent HS/Npt (HS) line for achieving binge levels of blood ethanol concentration (≥80 mg/dL BEC) in a four-hour period. In this work, we sought to evaluate differences in baseline and ethanol-induced c-Fos activation between the HS, iHDID1, and iHDID2 genetic lines in brain regions known to process the aversive properties of ethanol. METHODS: Male and female HS, iHDID1, and iHDID2 mice underwent an IP saline 2 3 g/kg ethanol injection. Brain sections were then stained for c-Fos expression in the basolateral/central amygdala (BLA/CeA), bed nucleus of the stria terminals (BNST), A2, locus coeruleus (LC), parabrachial nucleus (PBN), lateral/medial habenula (LHb/MHb), paraventricular nucleus of the thalamus (PVT), periaqueductal gray (PAG), Edinger-Westphal nuclei (EW), and rostromedial tegmental nucleus (RMTg). RESULTS: The iHDID1 and iHDID2 lines showed similar and distinct patterns of regional c-Fos; however, in no region did the two both significantly differ from the HS line together. CONCLUSIONS: These data lend further support to altered baseline or ethanol-induced activation in brain regions associated with processing the aversive properties of ethanol in the iHDID1 and iHDID2 genetic lines.

Evaluation of Anthelmintic Resistance and Exhaust Air Dust PCR as a Diagnostic Tool in Mice Enzootically Infected with Aspiculuris tetraptera.

The entry of infectious agents in rodent colonies occurs despite robust sentinel monitoring programs, strict quarantine measures, and stringent biosecurity practices. In light of several outbreaks with Aspiculuris tetraptera in our facilities, we investigated the presence of anthelmintic resistance and the use of exhaust air dust (EAD) PCR for early detection of A. tetraptera infection. To determine anthelmintic resistance, C57BL/6, DBA/2, and NCr nude mice were experimentally inoculated with embryonated A. tetraptera ova harvested from enzootically infected mice, followed by treatment with 150 ppm fenbendazole in feed, 150 ppm fenbendazole plus 5 ppm piperazine in feed, or 2.1 mg/mL piperazine in water for 4 or 8 wk. Regardless of the mouse strain or treatment, no A. tetraptera were recovered at necropsy, indicating the lack of resistance in the worms to anthelmintic treatment. In addition, 10 of 12 DBA/2 positive-control mice cleared the A. tetraptera infection without treatment. To evaluate the feasibility of EAD PCR for A. tetraptera, 69 cages of breeder mice enzootically infected with A. tetraptera were housed on a Tecniplast IVC rack as a field study. On day 0, 56% to 58% of the cages on this rack tested positive for A. tetraptera by PCR and fecal centrifugation flotation (FCF). PCR from EAD swabs became positive for A. tetraptera DNA within 1 wk of placing the above cages on the rack. When these mice were treated with 150 ppm fenbendazole in feed, EAD PCR reverted to pinworm-negative after 1 mo of treatment and remained negative for an additional 8 wk. The ability of EAD PCR to detect few A. tetraptera positive mice was investigated by housing only 6 infected mice on another IVC rack as a field study. The EAD PCR from this rack was positive for A. tetraptera DNA within 1 wk of placing the positive mice on it. These findings demonstrate that fenbendazole is still an effective anthelmintic and that EAD PCR is a rapid, noninvasive assay that may be a useful diagnostic tool for antemortem detection of A. tetraptera infection, in conjunction with fecal PCR and FCF.