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ObjectiveTo quantitatively investigate the changes in the total volume and contour density of hepatic oval cells （HOC） in hepatic lobules of rats with carbon tetrachloride （CCl4）-induced hepatic fibrosis. MethodsA total of 11 healthy male Sprague-Dawley rats were randomly divided into control group with 5 rats and hepatic fibrosis group with 6 rats， and CCl4 and olive oil suspension were injected subcutaneously twice a week， 3 mL/kg each time. After five weeks of hepatic fibrosis modeling， five liver tissue blocks with a size of about 1 mm3 were randomly selected from the liver of each rat to prepare one Epon812 epoxy resin-embedded ultrathin section， and the stereological method and transmission electron microscopy were used for the quantitative analysis of the total volume and contour density of HOC in the hepatic lobules of rats. In addition， four liver tissue blocks with a thickness of 2 mm were randomly selected from the remaining liver of each rat to prepare two paraffin-embedded Masson staining sections， and the degree of liver fibrosis in each rat was qualitatively evaluated according to the Metavir staging criteria for liver fibrosis. The independent-samples t test was used for comparison of continuous data between groups. ResultsThe quantitative stereological analysis showed that the total volume of HOC in hepatic lobules was 15.40±7.63 mm3 in the control group and 146.80±114.00 mm3 in the liver fibrosis group， and compared with the control group， the total volume of HOC in hepatic lobules of rats in the liver fibrosis group was significantly increased by 8.53 times （t=-2.551， P=0.031）； the contour density of HOC in hepatic lobules was 56.20±40.40 in the control group and 566.50±317.00 in the liver fibrosis group， and compared with the control group， the contour density of HOC in hepatic lobules of rats in the liver fibrosis group was significantly increased by 9.08 times （t=-3.539， P=0.006）. Qualitative observation showed that liver fibrosis stage of rats reached stage Ⅱ-Ⅲ according to the Metavir scoring criteria， and massive proliferation of HOC was observed around the proliferation site of hepatic stellate cells in the perisinusoidal space of rats. ConclusionCCl4 induces significant proliferation of HOC in hepatic lobules of rats with liver fibrosis.
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Objective To investigate the changes in the number of microglias and astrocytes in the spinal dorsal born in a rat model of phantom limb pain.Methods Eleven healthy adult SD rats of both sexes weighing 290-300 g were randomly divided into 2 groups:sham operation group (group S,n =5 ) and unilateral sciatic nerve transection group (group SNT,n =6).Phantom limb pain model was induced by resection of a 0.5 cm segment of unilateral sciatic nerve in group SNT.In group S unilateral sciatic nerve was exposed but not transected.The animals were observed for autotomy and scored (0 =no autotomy,13 =the worst autotomy) after operation and were sacrificed on the 28th day after operation.The L5 segment of the spinal cord was removed for determination of the number of microglials (by iba-1 immuno-histochemistry) and astrocytes (by GFAP immuno-histochemistry).Results In group S no animal developed autotomy.In group SNT autotomy started from the 2nd day after operation and the score reached 9-11.Compared with group S,the number of the microglias and astrocytes in the spinal dorsal horn was significantly decreased in the operated side in group SNT ( P ＜ 0.05 ).Conclusion The number of microglias and astrocytes in the spinal dorsal horn is decreased in animals with phantom limb pain.
RESUMO
Objective To investigate the changes in the number of synapses and neurons in the spinal dorsal horn in a rat model of phantom limb pain. Methods Eleven healthy adult SD rats of both sexes weighing 209-300 g were randomly divided into 2 groups: sham operation group (group S, n = 5) and phantom limb pain group (group P, n = 6). Phantom limb pain was induced by resection of a 0.5 cm segment of unilateral sciatic nerve in group P. In group S unilateral sciatic nerve was exposed but not transected. The animals were observed for autotomy and scored (0 = no autotomy, 13 = the worst autotomy) after operation and were sacrificed on the 28th day after operation. The L3-6 segment of the spinal cord was removed for determination of the number of neurons (by Nissl's staining) and synapses (by synaptophysin immuno-histochemistry).Results In group S no animal developed autotomy. In group P autotomy started from the 2nd day after operation and the score reached 9-11. The number of the neurons in the spinal dorsal horn in all 4 segments and the number of synapses in L3 and 16 segments were comparable between the two sides and the 2 groups. The number of synapses in the spinal dorsal horn of L4and L5 segment was significantly larger in the operated side than in the contralateral side in group P. Conclusion The number of synapses in the spinal dorsal horn significantly increases in animals with plantom limb pain which induces no increase in the number of neurons in the spinal dorsal horn.
