Stereological study of capillaries in CA1 of hippocampus and dentate gyrus in depression model rats

Abstract:

Objective：To investigate the changes of the capillaries in the CA1 of hippocampus and dentate gyrus（DG） in the depression rats induced by chronically unpredicted stress（CUS）. Methods：Male Sprague-Dawley（SD） rats were randomly divided into the con－trol group（n=10） and the model group（n=10）. The depression model was established by giving rats CUS for five weeks. The rats in control group did not receive CUS. The sucrose consumption test and open-field test were used to confirm whether the de－pression rat model was successfully made. After the depression model of rats was successfully made，5 rats were randomly se－lected from each group. The immunohistochemistrical technique and the stereological methods were used to quantitatively inves－tigate the capillaries in the CA1 of hippocampus and the DG. The other 5 rats in each group were used for the related molecular biol－ogy studies. Results：The rat weight[（314.81±31.52） g，（349.18±28.23） g，t=2.569，P=0.019]，the results of the sugar water prefer－ence[（82.37±8.44）%，（89.33±3.97）%，t=2.359，P=0.03] and the results of the open-field test[（48.30±39.49），（87.70±38.32），u=-1.988，P=0.047] were significantly different between two groups. The volumes of the hippocampus[（88.84±7.51） mm3，（99.89±12.55） mm3，t=2.388，P=0.028]，the CA1[（27.78±1.84） mm3，（32.38±3.69） mm3，t=3.522，P=0.004] and the DG[（21.02±2.61） mm3，（24.20±3.33） mm3，t=2.377，P=0.029] in model group were significantly lower than those in the control group. The total length[（8.454±1.010） m，（11.012±1.642） m，t=2.967，P=0.018]，total volume[（0.104±0.019） mm3，（0.151±0.021） mm3，t=3.720，P=0.006]，total surface area[（1.025±0.113） cm2，（1.589±0.313） cm2，t=3.794，P=0.013] and average diameter[（3.884±0.458） μm，（4.580±0.419） μm，t=2.509，P=0.036] of the capillaries in the hippocampal CA1 and the total volume[（0.078±0.021） mm，（0.117±0.024） mm，t=2.716，P=0.026]，total surface area[（0.838±0.184），（1.133±0.074） cm2，t=3.32，P=0.011] and average diameter[（3.611±0.493） μm，（4.630±0.635） μm，t=2.834，P=0.022] of the capillaries in the DG were significantly decreased in model group than in control group. Conclusion：Hippocampal capillary changes can be observed in the CA1 and the DG in depression model rats，which might be involved in the pathogenesis of depression.