Machiko Orita

Effects of saikosaponin-d on aminonucleoside nephrosis in rats

The effects of saikosaponin-d extracted from the roots of Bupleurum falcatum L. on aminonucleoside nephrosis were studied in rats. Urine protein excretion in rats receiving aminonucleoside alone was significantly elevated on the 2nd day after the last injection of aminonucleoside and reached a peak on the 11th day. Urinary protein on the 11th day was reduced by 48 and 46%, respectively in animals treated with saikosaponin-d from the 2nd and 8th day after the last injection of aminonucleoside. Electron microscopically, the degree of abnormality, e.g. loss or fusion of foot processes, in the glomerular epitherial cells was significantly lower in the rats treated with saikosaponin-d after aminonucleoside injection than in the rats treated with aminonucleoside alone. It is concluded that saikosaponin-d prevents the development of proteinuria induced by aminonucleoside in the rat.

Effects of saikosaponin‐d on enhanced CCl4‐hepatotoxicity by phenobarbitone

The effects of saikosaponin‐d extracted from the roots of Bupleurum falcatum L. on increased toxicity of CCl4 and increased activities of microsomal enzymes induced by phenobarbitone have been examined. Saikosaponin‐d showed protection against the CCl4‐hepatotoxicity enhanced by phenobarbitone. It also inhibited increases in the content of cytochrome P450 and NADPH‐cytochrome c reductase activity, which are induced by the phenobarbitone treatment, but the spectral characteristics of P450 were not altered. The rate of microsomal lipid peroxidation by NADPH and CCl4 was significantly lowered in‐vitro in rats pretreated with phenobarbitone and saikosaponin‐d compared with those pretreated with phenobarbitone alone.

Effects of Calcium Antagonists on the Erythrocyte Membrane

Abstract— The effects of dihydropyridine compounds nimodipine, nicardipine and NB818 (isopropyl methyl‐6‐carbamoyloxymethyl‐4‐(2,3‐dichlorophenyl)‐1,4‐dihydro‐2‐methyl‐3,5‐pyridine‐dicarboxylate) on erythrocyte membranes have been studied. These compounds showed protective effects against hypotonic haemolysis, but not against heat‐induced haemolysis. An increase in deformability of erythrocytes by these calcium antagonists was observed using a capillary tube centrifugal method. The erythrocytes showed slight stomatocytosis after 30 min of incubation with calcium antagonists, but did not show significant changes in mean corpuscular volume and ATP levels.

Effects of glycyrrhetinic acid on aminonucleoside nephrosis in rats

The effects of glycyrrhetinic acid (GA), an aglycon of glycyrrhizin extracted from the roots of Glycyrrhizae radix, on puromycin aminonucleoside (PA) nephrosis were studied in rats. Urine protein excretion in female rats (130g–150g) receiving PA (50 mg/kg) alone was significantly elevated on the 2nd day after injection of PA and reached a peak on the 14th day. Urinary protein on the 14th day was reduced to 74% in animals treated with GA (20 mg/kg) starting on the 2nd day after injection of PA. The increase in serum cholesterol and the decrease in serum protein were also suppressed by GA. Observation by electron microscopy revealed that the degree of abnormality in glomerular epithelial cells, i.e. loss or fusion of foot processes, was lower in the rats treated with GA after PA injection than in the rat treated with PA alone. Moreover, pretreatment with GA did not suppress urinary protein excretion but when it was given at the same time as PA and after PA a significant decrease in urinary protein excretion was observed.

Age-related changes of erythrocyte membrane in the senescence-accelerated mouse

Age-related changes in erythrocytes in senescence-accelerated mice (SAM-P) and control mice with normal aging characteristics (SAM-R) were examined. A significant decrease in the number of erythrocytes and significant increases in MCV and ATP levels were observed with aging in SAM-P, while no significant changes were seen in SAM-R. Erythrocytes in aged SAM-P were less fragile than those in aged SAM-R. The contents of cholesterol and phospholipids in erythrocyte membranes increased significantly in aged SAM-P, but the molar ratio of cholesterol/phospholipid decreased. The plasma cholesterol level of SAM-P decreased with aging. Changes such as those observed in SAM-P were not seen in SAM-R during the period of observation.

Effects of saikosaponins on hepatic damage induced by halothane and hypoxia in phenobarbital-pretreated rats

The effects of saikosaponins-a.-b1,-b2,-c, and-d on hepatic damage induced by halothane and hypoxia were investigated in the rat. Inhalation of halothane under a hypoxic condition significantly increased serum glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) levels in rats pretreated with phenobarbital compared with rats pretreated without phenobarbital. Pretreatment with saikosaponin (especially-a and-d) and with phenobarbital suppressed the increase in serum GOT and GPT levels in comparison with the rats treated with phenobarbital, halothane, and hypoxia. Histological observation also confirmed that pretreatment with saikosaponin had a protective effect against liver cell damage caused by halothane and hypoxia. Saikosaponins-a and-d, the most effective saikosaponins against hepatic damage, inhibited the increases in cytochrome P450 and NADPH-cytochromec reductase activity which are induced by phenobarbital treatment. Therefore, it is suggested that the cytoprotective effect of saikosaponin against halothane-induced hepatitis under hypoxia is caused by inhibition of phenobarbital stimulation of the enzyme system for hepatic drug metabolism.