RESUMO
Pregnant rats were treated intraperitoneally with a single dose of methotrexate (MTX) 90 mg/kg on gestation day (GD) 13, and fetal eyeballs were examined time-dependently from GD 13.5 to 15.5. Throughout the experimental period, the inner plate of the ocular cup in the MTX group was significantly thinner than that in the control group. In the inner plate of the ocular cup on GD 15 and 15.5, whereas a developed ganglion cell layer was observed in the control group, the ganglion cell layer in the MTX group was undeveloped and indistinguishable. Disturbance of the arrangement of lens fiber cells, narrowing of the hyaloid cavity of the optic cup, and hypoplasia of optic nerve fibers were observed in the MTX group on GD 15 and 15.5. Increase of pyknosis and decrease of mitosis were induced in the optic cup and the lens epithelium of the MTX group. In the inner plate of the optic cup and the lens epithelium of the MTX group, the cleaved caspase-3- and TUNEL-positive rates increased significantly throughout the experimental period. The phospho-histone H3-positive rate in the inner plate of the optic cup decreased significantly from GD 13.5 to 14.5, and it recovered on GD 15. On the other hand, the phospho-histone H3-positive rate in the lens epithelium decreased significantly throughout the experimental period. These results suggested that optic tissue on GD 13 in rats was sensitive to MTX.
RESUMO
OBJECTIVE: To develop a new model of vascular dementia for evaluating Chinese medicine prescriptions. METHODS: Eighty-eight male Wistar rats were randomly divided into 4 groups. At d00, d42, d70, d98 (ni=20, 20, 24, 24) during fatty-feeding, rats in each group were further divided into 10 or 12 subgroups (ni=2), respectively. Lacunar stroke were replicated with the injection of thrombi which coagulated artificially from itself blood. The median lethal doses (LD50) were regressed from accumulative mortality in each geometric thrombus doses (k=0.75, 0.5, 0.85, 0.85), respectively. The degree of vascular dementia was evaluated as exploratory, learning and memorizing abilities. The median effective dose of thrombus for replicating rat model was regressed from dementia scores which were derived from the abilities. The linear correlation was regressed between the values of LD50 or effective dose (ED50) and the durations (days) of hypercholesterolemia. This model of vascular dementia was pathologically confirmed as the neural injuries from lacunar stroke in rats. RESULTS: The hypercholesterolemia was indicated as elevated total cholesterol, triglyeerides low-density lipoprotein cholesterol, and decreased high-density lipoprotein cholesterol. The values of LD50 with its 95% confidence intervals (CI) were 1525.0 (1361.0-1709.0), 584.3 (490.1-696.6), 168.7 (163.7-173.8), or 62.4 (59.5-65.4) mg/mL, at d00, d42, d70, and d98, respectively. There is a linear regression between the values of LD50 and the durations of hypercholesterolemia (y=-15.33x+1390.0, r=0.963, P<0.05). The values of ED50 with its 95% CI were 528.8 (340.5-821.4), 217.0 (20.84-2259.0), 96.3 (23.4-402.6), or 47.0 (43.7-50.6) mg/mL from dementia score, at d00, d42, d70, and d98, respectively. There is a linear regression between the values of ED50 and the durations of hypercholesterolemia (y=-4.992x+484.2, r=0.965, P<0.05). The neural injuries were demonstrated as neural degeneration and necrosis. CONCLUSIONS: For evaluating Chinese medicine, a model of vascular dementia in rats is set up with the lacunar stroke from self-thrombosis during hypercholesterolemia. This model from lacunar stroke is useful to investigate the pathogenesis and treatment of vascular dementia.
