| Objective In this study, to explore impact of early olfactory deprivation on behaviourand expression of Extrasynaptic GABA-A receptor localized on hippocampus in rats.Methods Each thirty-six3-old-rats and8-old-rats were divided randomly into3groups: blank control group, experimental group and sham operation group. Experimentalgroup:3-day-old experimental group and8-day-old experimental group of rats establishedby chloroform fixed point injection to damage the nasal mucosa. Sham operation group:the same method of the experimental group by dropping physiological saline instead ofdropping chloroform. Blank control group: without any treatment. Each group had beendetected by MWM before beheaded at4weeks ages, and taken the brain organization toconduct the Nissl Staining, δ andα5subunits immunohistochemistry and q-PCR researchin hippocampus.Result1. Behavioral change:(1) Escape latency：Experimental group of3days,3daysgroup and sham operation group were compared with the blank and experimental group of8days,8days in sham operationgroup and control group were compared. The result showedthat The3day of the experiment group escape latency in experiment second, third and fourthcompared with that of3days group and blank control group sham operation were markedlyincreased. The difference has statistical significance (P<0.01).3days of sham operationgroup and blank control group had no significant difference (P>0.05). And the8day of theexperiment group4, experiment the escape latency in8days with false operation group andblank control group two showed no statistical difference (P>0.05).(2) Target quadrant location time：The result showed that3days in the experimental group compared with thetarget quadrant in which time3days sham group and the control group were significantlylower. The results were statistically significant (P<0.01). There is no significant differencebetween the3days sham group with the control group (P>0.05). And between eight days inthe experimental group, eight days sham group and control group pairwise comparison, theresults were not statistically different (P>0.05).2. Morphological changes:(1) Nissl: Theresult showed that3days in the experimental group and CA3hippocampal dentate gyrusneurons cell disorder, cell spacing increased cytoplasmic Nissl reduced dentate gyrus granulecell boundary missing, spacing widened, loosely arranged disorder. Compared with thecomparison group within8days within3days group, significant differences in hippocampaldentate gyrus and CA3region of the number of neurons were not (P>0.05).(2)Immunohistochemistry：α5subunit associated protein related quantitative analysis three daysin the experimental group outside the dentate gyrus synaptic GABAA receptor δ subunit andCA3regions decreased. And3days sham group and control group comparisons werestatistically different (P<0.01).8days in the experimental group, carried out between8dayssham group and control group pairwise comparison, the difference was not statisticallysignificant(P>0.05).(3) q-PCR: The result showed that3days in the experimental group inthe hippocampus extrasynaptic GABAA receptor δ subunitα5subunit mRNA expressiondecreased. And3days sham group and control group were statistically different (P<0.01).8days in the experimental group, carried out between8days sham group and control grouppairwise comparison, the difference was not statistically significant (P>0.05).Conclusion A significant reduction in3days in the experimental group SD rathippocampus extrasynaptic GABAA receptor δ subunit protein and mRNA expressioncorrelated withα5subunits. That early olfactory deprivation not only reduces the space oflearning and memory SD rats. Neurons in the hippocampus and build cases and contained inits lower extrasynaptic GABAA receptor δ subunit expression andα5subunit also has a significant impact. However, its exact mechanism needs further study. |
PDF Full Text Request