AIM: To investigate the effect of peripheral administration of arginine vasopressin (AVP) on lipopolysaccharide (LPS)-induced fever and hyperalgesia in rats and its relationship with interleukine-1β (IL-1β) and prostaglandin E2 (PGE2).METHODS: The core temperature (Tc), brown adipose tissue (BAT) temperature and activity were measured by telemetry in adult male Sprague-Dawley rats at an ambient temperature of 23 ℃ during a 12 h light/12 h dark photoperiod (lights on at 06:00 and lights off at 18:00).The rats were intraperitoneally injected with LPS (50 μg/kg), AVP (10 μg/kg) or V1a vasopressin receptor antagonist (V1a antagonist, 30 μg/kg) at 10:00 or 11:30.Hyperalgesia was assessed by measuring the latency to withdraw a hindpaw from radiant heat (Hargreaves test).The concentrations of IL-1β and PGE2 in the serum were tested by ELISA.RESULTS: Intraperitoneal administration of LPS induced periods of biphasic fever accompanied by hyperalgesia.AVP reversed LPS-induced fever, and decreased the hyperalgesia and BAT thermogenesis.Peripheral administration of V1a antagonist enhanced the fever produced by LPS, but did not affect the hyperalgesia.AVP significantly attenuated LPS-induced IL-1β and PGE2 production.CONCLUSION: Peripheral administration of AVP reverses LPS-induced fever and decreases hyperalgesia by reduction of BAT thermogenesis and inhibition of IL-1β and PGE2.Endogenous AVP attenuates the fever induced by LPS, but does not affect the nociceptive thresholds.

Cysticercosis,caused by the larval stage of the tapeworm Taenia pisiformis,known as Cysticercus pisiformis,is a parasitic ailment affecting lagomorphs,particularly domestic rabbits,posing a threat to the rabbit industry and the safety of rabbit meat products.This study aims to i-dentify the distribution of the TPO18 antigen in Cysticercus pisiformis and Taenia pisiformis and establish an indirect enzyme-linked immunosorbent assay(ELISA)for detecting antibodies against rabbit cysticercosis.The research involved the prokaryotic expression of the 18 kDa antigen of rabbit Cysticercus pisiformis and the isolation of soluble TPO18 protein post-purification.Immuni-zing rabbits with the TPO18 protein resulted in the production of polyclonal antibodies with a titer of up to 1∶51 200.Western blot analysis validated the antigenicity of the polyclonal antibodies a-gainst total proteins from rabbit Cysticercus pisiformis,Taenia pisiformis and the recombinant TPO18 protein.Immunohistochemistry revealed the distribution of the TPO18 antigen in rabbit Cysticercus pisiformis and Taenia pisiform is,indicating the effective reactivity of the polyclonal antibodies with total proteins from both parasites and the recombinant TPO18 protein.TPO18 an-tigen in rabbit Cysticercus pisiformis predominantly localized in the germinal layer and the paren-chyma,while in Taenia pisiformis,it was mainly present in the suckers,sucker peripheries,collec-ting duct upper cells,and parenchyma.An indirect ELISA based on the TPO18 antigen was devel-oped using the recombinant antigen,and its technical parameters were optimized.The optimized ELISA conditions included a serum dilution of 1∶100,antigen coating concentration of 5 mg/L,coating for 1 h at 37 ℃ followed by overnight incubation at 4 ℃,blocking with 1％BSA for 60 min at 37 ℃,serum reaction for 60 min,secondary antibody dilution at 1∶1 000,secondary antibody incubation for 60 min,substrate reacting for 15 min,with a cutoff value of 0.295.Sensitivity,speci-ficity,and repeatability tests of the ELISA demonstrated high sensitivity and specificity without cross-reactivity with positive sera of rabbit hemorrhagic disease virus,Hepatic coccidiosis,Eimer-ia stiedae,or Toxoplasma gondii.The intra-and inter-assay coefficients of variation were both less than 7％,indicating excellent repeatability.Application of this ELISA,compared to postmortem ex-amination,on 86 clinical serum samples showed a concordance rate of 97.7％.In conclusion,this study successfully established an indirect ELISA for detecting antibodies against rabbit Cysticercus pisiformis,presenting a novel monitoring approach for assessing rabbit infections with Cysticer-cus pisiformis.

Many people affected by fragile X syndrome (FXS) and autism spectrum disorders have sensory processing deficits, such as hypersensitivity to auditory, tactile, and visual stimuli. Like FXS in humans, loss of Fmr1 in rodents also cause sensory, behavioral, and cognitive deficits. However, the neural mechanisms underlying sensory impairment, especially vision impairment, remain unclear. It remains elusive whether the visual processing deficits originate from corrupted inputs, impaired perception in the primary sensory cortex, or altered integration in the higher cortex, and there is no effective treatment. In this study, we used a genetic knockout mouse model (Fmr1^KO), in vivo imaging, and behavioral measurements to show that the loss of Fmr1 impaired signal processing in the primary visual cortex (V1). Specifically, Fmr1^KO mice showed enhanced responses to low-intensity stimuli but normal responses to high-intensity stimuli. This abnormality was accompanied by enhancements in local network connectivity in V1 microcircuits and increased dendritic complexity of V1 neurons. These effects were ameliorated by the acute application of GABA_A receptor activators, which enhanced the activity of inhibitory neurons, or by reintroducing Fmr1 gene expression in knockout V1 neurons in both juvenile and young-adult mice. Overall, V1 plays an important role in the visual abnormalities of Fmr1^KO mice and it could be possible to rescue the sensory disturbances in developed FXS and autism patients.
Animals ; Disease Models, Animal ; Fragile X Mental Retardation Protein/metabolism* ; Fragile X Syndrome/metabolism* ; Humans ; Mice ; Mice, Knockout ; Neurons/metabolism*