The comparison of vitamin C and vitamin E on the protein oxidation of diabetic rats

1 We measured the plasma glucose and the glycosylated haemoglobin at the time of sacrifice in streptozotocin‐induced diabetic mellitus (DM) rats. 2 In diabetic rats, plasma glucose and glycosylated haemoglobin was increased as compared with normal rats, and vitamin E inhibited the increase of glycosylated haemoglobin level but vitamin C had no effect. 3 The peroxidized proteins and lipids from the diabetic organs such as liver or kidney were measured to assess the oxidative damage. The 2,4‐dinitrophenyl‐hydrazine (DNPH) incorporation method was used to measure the peroxidized protein. In diabetic rats, DNPH incorporation was increased as compared with normal rats and vitamin E also inhibited the increase of DNPH incorporation but vitamin C had no effect. It suggests that the protein oxidation occurred on the liver in diabetic rats and the oxidative stress is general in the diabetic condition. 4 We measured the systolic arterial pressure and mean arterial pressure in normal rats, nephrectomy (NEPH)‐rats, diabetic rats (DM), and NEPH‐diabetic rats (NEPH‐DM). Blood pressure was significantly increased in DM and NEPH‐DM as compared with normal rats. 5 In conclusion, plasma glucose, glycosylated haemoglobin, and the oxidation of proteins or lipid were increased in diabetic rats. Vitamin E decreased the plasma glucose, glycosylated haemoglobin and the oxidation of proteins and lipid, but vitamin C had no effects.     

The comparison of vitamin C and vitamin E on the protein oxidation of diabetic rats

1 We measured the plasma glucose and the glycosylated haemoglobin at the time of sacrifice in streptozotocin-induced diabetic mellitus (DM) rats. 2 In diabetic rats, plasma glucose and glycosylated haemoglobin was increased as compared with normal rats, and vitamin E inhibited the increase of glycosylated haemoglobin level but vitamin C had no effect. 3 The peroxidized proteins and lipids from the diabetic organs such as liver or kidney were measured to assess the oxidative damage. The 2,4-dinitrophenyl-hydrazine (DNPH) incorporation method was used to measure the peroxidized protein. In diabetic rats, DNPH incorporation was increased as compared with normal rats and vitamin E also inhibited the increase of DNPH incorporation but vitamin C had no effect. It suggests that the protein oxidation occurred on the liver in diabetic rats and the oxidative stress is general in the diabetic condition. 4 We measured the systolic arterial pressure and mean arterial pressure in normal rats, nephrectomy (NEPH)-rats, diabetic rats (DM), and NEPH-diabetic rats (NEPH-DM). Blood pressure was significantly increased in DM and NEPH-DM as compared with normal rats. 5 In conclusion, plasma glucose, glycosylated haemoglobin, and the oxidation of proteins or lipid were increased in diabetic rats. Vitamin E decreased the plasma glucose, glycosylated haemoglobin and the oxidation of proteins and lipid, but vitamin C had no effects.     

高效液相色谱法测定复方芦丁片中维生素C的含量

目的：建立复方芦丁片中维生素C含量的测定方法。方法采用高效液相色谱法,0.02mol· L^-1乙酸铵溶液-甲醇（95∶5）为流动相;流速为1.0mL· min^-1;检测波长为267nm。结果维生素C的质量浓度在0.01～0.10mg· mL^-1范围内与峰面积呈良好的线性关系,r＝0.9999,平均回收率为98.38％,RSD为0.96％。结论该方法简便、准确、重复性好,可用于测定复方芦丁片中维生素C的含量。     

Combined antioxidant effects of rutin and vitamin C in Triton X-100 micelles

UV-vis spectra, fluorescence emission spectra and cyclic voltammetric measurements were used to study the influence of Vitamin C on the antioxidant of rutin in Triton X-100 micelles. Rutin can be located in Triton X-100 micelles spontaneously through hydrophobic force, and the binding constant K between rutin and Triton X-100 increases with the rutin concentration. The embedment of two hydroxyl groups on rutin into the more hydrophobic micellar microenvironment makes the oxidation of rutin harder and the radical scavenging activity decrease. With low concentration of Vitamin C, the antioxidant capacity of rutin against hydroxyl radical is enhanced, while that capacity is partly inhibited when the concentration of Vitamin C become higher.     

Effects of Rutin on Lipid Profile in Hypercholesterolaemic Rats

Abstract: Rutin (3, 3′, 4′, 5, 7‐pentahydrohyflavone‐3‐rhamnoglucoside) is a flavonoid of the flavonol type. Rutin is found in many plants and is also an important dietary constituent of food and plant‐based beverages. Rutin has several pharmacological properties including antioxidant and cardioprotective activities. Also, it was identified that rutin is the major low‐density lipoprotein (LDL) antioxidant compound of mulberry in an in vitro study. The effects of rutin were tested by using it as a supplement in a high‐cholesterol diet. Male rats were fed a high‐cholesterol diet (1 ml/100 g) for 4 weeks with rutin (10 or 100 mg/kg) or rutin 100 mg/kg and lovastatin supplementation to study the hypocholesterolaemic effects of rutin on plasma lipid levels, hepatic enzyme activity, and liver tissue. Feeding the animals a high‐cholesterol diet resulted in marked hypercholesterolaemia and increased the serum level of LDL cholesterol (LDL‐C). Rutin (at 100 mg/kg) alone or in combination with lovastatin significantly reduced the levels of total cholesterol, and LDL‐C and also markedly decreased liver enzymes and weight in animals with a high‐cholesterol diet. Our findings show that 100 mg/kg of rutin alone or with lovastatin supplementation lowered liver weight and enzymes as well as plasma total cholesterol and LDL. The hepatic histopathological results reflect the correlation of rutin and lovastatin combination with both liver weight and the levels of plasma total cholesterol and LDL‐C. These results indicate that rutin in combination with lovastatin has increased anti‐hypercholesterolaemic effects in an animal model.     

Direct administration of rutin does not protect against catecholamine cardiotoxicity

High levels of catecholamines are cardiotoxic and may trigger acute myocardial infarction (AMI). Similarly, the synthetic catecholamine isoprenaline (ISO) evokes a pathological state similar to AMI. During AMI there is a marked increase of free iron and copper which are crucial catalysts of reactive oxygen species formation. Rutin, a natural flavonoid glycoside possessing free radical scavenging and iron/copper chelating activity, may therefore be potentially useful in reduction of catecholamine cardiotoxicity as was previously demonstrated after its long-term peroral administration. Male Wistar:Han rats received rutin (46 or 11.5 mg kg(-1) i.v.) alone or with necrogenic dose of ISO (100 mg kg(-1) s.c.). Haemodynamic parameters were measured 24h after drug application together with analysis of blood, myocardial content of elements and histological examination. Results were confirmed by cytotoxicity studies using cardiomyoblast cell line H9c2. Rutin in a dose of 46 mg kg(-1) aggravated ISO-cardiotoxicity while the dose of 11 mg kg(-1) had no effect. These unexpected results were in agreement with in vitro experiments, where co-incubation with larger concentrations of rutin significantly augmented ISO cytotoxicity. Our results, in contrast to previous studies in the literature, suggest that the reported positive effects of peroral administration of rutin were unlikely to have been mediated by rutin per se but probably by its metabolite(s) or by some other, at this moment, unknown adaptive mechanism(s), which merit further investigation.     

Antihyperglycaemic and antioxidant effect of rutin, a polyphenolic flavonoid, in streptozotocin-induced diabetic wistar rats

Flavonoids are non-nutritive dietary components that are widely distributed in plants. The present study investigated the antihyperglycaemic and antioxidant effect of rutin, a polyphenolic flavonoid in normal and streptozotocin-induced diabetic Wistar rats. Diabetes as induced in rats by an intraperitoneal injection of streptozotocin. Rutin was orally administered to normal and diabetic rats for a period of 45 days. Fasting plasma glucose, glycosylated haemoglobin, thiobarbituric acid reactive substances and lipid hydroperoxides were significantly (P<0.05) increased, whereas insulin, C-peptide, total haemoglobin, protein levels, non-enzymic antioxidants (glutathione, vitamin C, vitamin E and ceruloplasmin) were decreased significantly (P<0.05) in diabetic rats. Oral administration of rutin to diabetic rats significantly (P<0.05) decreased fasting plasma glucose, glycosylated haemoglobin and increased insulin, C-peptide, haemoglobin and protein levels. Administration of rutin also decreased thiobarbituric acid reactive substances and lipid hydroperoxides and increased the non-enzymic antioxidants significantly (P<0.05). Treatment of normal rats with rutin did not significantly (P<0.05) alter any of the parameters studied. These results show that rutin exhibits antihyperglycaemic and antioxidant activity in streptozotocin-induced diabetic rats.     

Protective effect of rutin on LPS-induced acute lung injury via down-regulation of MIP-2 expression and MMP-9 activation through inhibition of Akt phosphorylation

Lipopolysaccharide (LPS), also called endotoxin, is the important pathogen of acute lung injury (ALI), which is a clinical syndrome that still lacks effective therapeutic medicine. Rutin belongs to vitamin P and possesses various beneficial effects. In this study, we investigate the potential protective effects and the mechanisms of rutin on LPS-induced ALI. Pre-administration with rutin inhibited LPS-induced arterial blood gas exchange and neutrophils infiltration in the lungs. LPS-induced expression of macrophage inflammatory protein (MIP)-2 and activation of matrix metalloproteinase (MMP)-9 were suppressed by rutin. In addition, the inhibitory concentration of rutin on phosphorylation of Akt was similar as MIP-2 expression and MMP-9 activation. In conclusion, rutin is a potential protective agent for ALI via suppressing the blood gas exchange and neutrophil infiltration. The mechanism of rutin is down-regulation of MIP-2 expression and MMP-9 activation through inhibition of Akt phosphorylation.     

芦丁对脂多糖诱导急性肺损伤小鼠的抗氧化应激作用

目的 探讨芦丁对脂多糖(lipopolysaccharide,LPS)诱导的小鼠急性肺损伤氧化应激失衡的作用。方法 将50只C57小鼠随机分为5组(n=10),分别为对照组、模型组和芦丁低、中、高剂量(25,50,100 mol·kg^-1)组。LPS注射6 h后测小鼠血气,取肺组织进行病理观察,测肺组织的湿干比、丙二醛(MDA)含量、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GPx)、超氧化物歧化酶(SOD)活性。结果 与对照组相比,模型组的肺组织病理改变和肺组织的湿干比,二氧化碳分压[p(CO₂)],呼吸频率(RR)和MDA含量明显增加,而氧分压[p(O₂)]和pH值、CAT、GPx和SOD活性明显降低。与模型组相比,芦丁组的肺组织病理改变和肺组织湿干比,p(CO₂)、呼吸率和MDA含量呈浓度依赖性减少,而p(O₂)和pH值、CAT、GPx和SOD活性呈浓度依赖性增高。结论 芦丁可呈浓度依赖性抑制氧化应激而减轻脂多糖诱导的小鼠急性肺损伤。     

Hyperlipidemia-induced lipotoxicity and immune activation in rats are prevented by curcumin and rutin

We assessed the effects of curcumin, rutin, and the association of rutin and curcumin in organs of hyperlipidemic rats. Rutin and curcumin have notable antioxidant and anti-inflammatory actions, so we hypothesized that their association would enhance their beneficial effects. Hyperlipidemia results in lipotoxicity and affects several organs. Lipotoxicity is not only an outcome of lipid accumulation in non-adipose tissues but also a result of the hyperlipidemia-associated inflammation and oxidative stress. Wistar rats were treated with rutin and curcumin for 30 days before the induction of acute hyperlipidemia by Poloxamer-407. After 36 h, the animals were euthanized for collection of blood and organs. Untreated hyperlipidemic rats showed higher uric acid and albumin levels in the serum and increased spleen size and ADA activity. Rutin, curcumin and the association reduced the spleen size by 20% and ADA activity by 23, 28, and 27%, respectively. Rats pretreated with rutin showed reduced lipid damage in the liver (40%) and the kidney (44%), and the protein damage was also reduced in the liver (75%). The lipid damage was decreased by 40% in the liver, and 56% in the kidney of rats pretreated with curcumin. The association reduced lipid damage by 50% and 36%, and protein damage by 77% and 64% in the liver and kidney, respectively. Rutin better prevented the decrease in the antioxidant defenses, increasing SOD by 34%, CAT by 246% and GST by 84% in the liver, as well as SOD by 119% and GST by 190% in the kidney. Also, analyses of blood and spleen parameters of untreated and pretreated non-hyperlipidemic rats showed no signs of immunotoxicity. Despite showing protective effects, the association did not perform better than the isolated compounds. Here, we showed that rutin and/or curcumin reestablished the immune homeostasis and redox balance disrupted by hyperlipidemia in peripheral organs of rats.     

Effect of rutin on warfarin anticoagulation and pharmacokinetics of warfarin enantiomers in rats

Objectives The effects of the flavonoid rutin on the anticoagulant activity of oral warfarin and the protein binding and pharmacokinetics of its enantiomers were investigated in rats. Methods A single dose of racemic warfarin, 1.5 mg/kg, was administered orally to rats either alone or on day 5 of an 8‐day oral regimen of rutin, 1 g/kg daily. Results Rutin reduced the anticoagulant effect of racemic warfarin, evident as a 31% reduction in the area under the prothrombin complex activty–time curve (P < 0.05). Key findings Rutin had no apparent effect on pre‐treatment baseline blood coagulation. It enhanced the in‐vitro serum protein binding of S‐ and R‐warfarin (reflected by 40% and 26% reductions in unbound fraction, respectively), and thus restricted distribution by 33 and 21%, respectively. Treatment with rutin significantly decreased the elimination half‐life of S‐warfarin by 37% as a result of the 69% increase in unbound clearance of the S‐enantiomer. This effect was attributed to a significant 77% increase in the unbound formation clearance of the overall oxidative and reductive metabolites, and an increase in the unbound renal clearance of the more potent S‐enantiomer of warfarin. Conclusions Concurrent rutin administration is likely to reduce the anticoagulant effect of racemic warfarin, reflecting a significant decrease in the elimination half‐life of the more potent S‐enantiomer.     

Effects of rutin on acrylamide-induced neurotoxicity

Background

Rutin is an important flavonoid that is consumed in the daily diet. The cytoprotective effects of rutin, including antioxidative, and neuroprotective have been shown in several studies. Neurotoxic effects of acrylamide (ACR) have been established in humans and animals. In this study, the protective effects of rutin in prevention and treatment of neural toxicity of ACR were studied.

Results

Rutin significantly reduced cell death induced by ACR (5.46 mM) in time- and dose-dependent manners. Rutin treatment decreased the ACR-induced cytotoxicity significantly in comparison to control (P <0.01, P < 0.001). Rutin (100 and 200 mg/kg) could prevent decrease of body weight in rats. In combination treatments with rutin (50, 100 and 200 mg/kg), vitamin E (200 mg/kg) and ACR, gait abnormalities significantly decreased in a dose-dependent manner (P < 0.01 and P < 0.001). The level of malondialdehyde significantly decreased in the brain tissue of rats in both preventive and therapeutic groups that received rutin (100 and 200 mg/kg).

Conclusion

It seems that rutin could be effective in reducing neurotoxicity and the neuroprotective effect of it might be mediated via antioxidant activity.     

A comparison of the effects of paraquat and diquat on the water content of rat lung and the incorporation of thymidine into lung DNA

Following the administration to rats of approximately equitoxic doses of paraquat and diquat by intraperitoneal injection, the pattern of mortality was different. After dosing with paraquat, there were no deaths in the first 24 h, whereas 22% of the rats given diquat died in this period. The largest proportion (34%) of the rats which died following paraquat administration, did so on the third day after dosing. The death of paraquat-poisoned rats has been shown to be related to lung damage as measured by a greatly increased water content. There was no similar increase in the water content of lungs taken from rats poisoned with diquat. Thymidine incorporation into lung DNA was significantly decreased one day after dosing with both paraquat and diquat, but became greatly elevated in a proportion of those rats given paraquat which survived 3 days after dosing. In diquat-poisoned rats, thymidine incorporation into lung DNA remained depressed for at lease 8 days.It is concluded that: (1) most rats given paraquat by intraperitoneal injection die from acute lung damage characterised by a dramatic increase in the lung water content; (2) only a small proportion die many days later from lung fibrosis characterised by an increase in thymidine incorporation into DNA; and (3) diquat does not cause lung damage as characterised by increases in either the water content of lung or increases in thymidine incorporation into DNA.     

芪藤通络饮防治实验性糖尿病大鼠周围神经病变发生的可能机制

目的探讨芪藤通络饮防治糖尿病多发性神经病变(DPN)的可能机制。方法以链脲佐菌素(STZ)诱导糖尿病大鼠模型,中药汤剂灌胃,观测体重、血糖、糖化血红蛋白的变化,坐骨神经的组织形态学改变。用免疫组化方法检测坐骨神经中神经生长因子(NGF)和神经肽P物质(SP)蛋白表达量。结果中药组大鼠坐骨神经病变比模型组轻,坐骨神经中NGF和SP蛋白表达与模型组相比明显要多(P<0.05)。结论芪藤通络饮能防治实验性糖尿病多发性神经病变大鼠坐骨神经病变,其作用可能是通过促进大鼠坐骨神经NGF和SP蛋白的表达实现的。     

Lipid Peroxidation in the Lung of Rats Exposed to Endotoxin: Effect of Vitamin E Supplementation

Abstract: The aim of this work was to investigate the possibility for development of peroxidation in the lung of rats injected with endotoxin. The effect of vitamin E supplementation of the rats was also investigated. Vitamin E supplementation by itself did not cause visible differences or any pathological changes in the lung structure of rats as shown by routine histological examinations. The endotoxin-induced alterations of the lung structures were well expressed in vitamin E-non-supplemented rats, while they were rather negligible in vitamin E-supplemented rats. It was established also that endotoxin caused a 50% increase of the conjugated dienes in the lung of vitamin E-non-supplemented rats. For vitamin E-supplemented rats this increase was less than 13.5%. The fluorescent lipofuscine-like products of lipid peroxidation (known as one of the end products of lipid peroxidation) increased by 120% in vitamin E-non-supplemented rats after exposure to endotoxin, while in vitamin E-supplemented rats this increase did not exceed 26%. Exposure to endotoxin of both vitamin E-non-supplemented and vitamin E-supplemented rats did not lead to significant changes of the lung fatty acid composition. On the basis of these results we assumed that the endotoxin-induced changes of lung structures involve, at least in part, free radical-mediated damage of the lung membrane lipids and proteins.     

Effect of oral vitamin E administration on acute gastric mucosal lesion progression in rats treated with compound 48/80, a mast cell degranulator

The effect of oral vitamin E administration on acute gastric mucosal lesion progression was examined in rats treated once with compound 48/80 (C48/80) (0.75 mg/kg, i.p.) in comparison with that of subcutaneously administered superoxide dismutase (SOD) plus catalase (CAT). Vitamin E (50, 100 or 250 mg/kg) administered at 0.5 h after C48/80 treatment reduced progressive gastric mucosal lesions at 3 h after the treatment dose-dependently, like SOD plus CAT administered at the same time point. The gastric mucosa of C48/80-treated rats had decreased Se-glutathione peroxidase activity and vitamin E, ascorbic acid, and hexosamine contents and increased myeloperoxidase and xanthine oxidase activities and thiobarbituric acid reactive substances content at 3 h after the treatment. Administered vitamin E attenuated all these changes found at 3 h after C48/80 treatment dose-dependently, like administered SOD plus CAT. C48/80-treated rats administered with vitamin E (100 or 250 mg/kg) had higher gastric mucosal vitamin E content than C48/80-untreated rats. Neither administered vitamin E nor SOD plus CAT had any effect on the increases in serum serotonin and histamine concentrations and the decrease in gastric mucosal blood flow found at 3 h after C48/80 treatment. In the gastric mucosa of C48/80-untreated rats administered with vitamin E, thiobarbituric acid reactive substances content decreased with an increase in vitamin E content. These results indicate that orally administered vitamin E prevents acute gastric mucosal lesion progression in C48/80-treated rats possibly by suppressing oxidative stress, neutrophil infiltration, and mucus depletion in the gastric mucosa like administered SOD plus CAT.     

Modified mutagen activation in hepatic fractions from rats fed dietary rutin--interaction between gut flora and host metabolism

Male Sprague-Dawley rats were fed a purified diet or one supplemented with the glycosidic plant flavonoid (+)rutin for 14 days. Rutin treatment significantly increased caecal bacterial beta-glucosidase activity (responsible for the conversion of rutin to the flavonoid quercetin) and there was an associated increase in the capacity of hepatic fractions (S-9) to activate the food pyrolysis products IQ, MeIQ and MeIQx to bacterial mutagens in vitro. Hepatic conversion of aflatoxin B1 to a mutagen was unaltered while in vitro activation of quercetin was significantly lower in tissue fractions from the rutin-fed rats compared with those from controls. Rutin treatment was without effect, however, on a number of hepatic cytochrome P-450-dependent mixed-function oxidase activities. The results suggest that products of bacterial metabolism of rutin formed in the hindgut may influence the activity of hepatic enzymes involved in the activation of certain classes of mutagen.     

Rutin ameliorates kidney interstitial fibrosis in rats with obstructive nephropathy

Rutin reportedly conveys many beneficial effects, including renoprotection; however, it has not yet been demonstrated to have a renoprotective effect against obstructive nephropathy. The present study is the first to show a protective effect of rutin against obstructive renal injury induced by unilateral ureteral obstruction (UUO). A total of 24 male Wistar rats were randomly divided into four groups of six rats each, including vehicle- or rutin-treated sham operated groups, and vehicle- or rutin-treated UUO groups. Rats received daily oral gavage of rutin (100 mg/kg) for 2 weeks. All rats were euthanized on postoperative day 14. Histological findings showed that rutin administration significantly reduced renal interstitial injury and suppressed interstitial collagen deposits in UUO rats. Moreover, rutin decreased macrophage infiltration, proinflammatory cytokine expression and phosphorylation of nuclear factor-κB p65. Furthermore, rutin inhibited extracellular matrix accumulation by reducing expression of type I/III collagen and fibronectin. Rutin also prevented the epithelial-mesenchymal transition processes of renal tubular cells by decreasing α-smooth muscle actin expression and retaining E-cadherin expression. These effects of rutin were in parallel with the reductions in Smad3 activity and pivotal to the fibrogenic potential of TGF-β1. Taken together, the renoprotective effects of rutin in obstructive nephropathy were likely due to anti-inflammatory effects and inhibition of TGF-β1/Smad3 signaling.     

Effects of rutin and harmaline on rat reflux oesophagitis

1. This study was aimed at evaluating the effect of rutin and harmaline (1-methyl-7-methoxy-3,4-dihydro-beta-carboline) on the development of the surgically induced reflux oesophagitis, on gastric secretion, lipid peroxidation, polymorphonucleocytes (PMNs) accumulation, superoxide and hydroxyl radical production in PMNs, cytokine [interleukin-1beta (IL-1beta), tumour necrosis factor-alpha (TNF-alpha)] production in blood and [Ca2+]i mobilization in PMNs. 2. Rutin and harmaline significantly prevented the development of reflux oesophagitis and gastric secretion. Treatments of oesophagitis rats with rutin and harmaline inhibited lipid peroxidation, and myeloperoxidase (MPO) in the oesophagus in comparison with untreated rats. 3. Superoxide anion and hydrogen peroxide production in 1 microm formylmethionylleucylphenylalanine (fMLP)- or 0.1 microg ml-1N-phorbol 12-myristate 13-acetate (PMA)-activated PMNs was inhibited by rutin and harmaline in a dose-dependent fashion. Rutin and harmaline effectively scavenged the hydroxyl radical and hydrogen peroxide. Treatments of oesophagitis rats with rutin and harmaline inhibited IL-1beta production in the oesophagus in comparison with untreated rats, but TNF-alpha production was not affected by rutin and harmaline. The fMLP-induced elevation of [Ca2+]i was inhibited by rutin. 4. The results of this study suggest that rutin and harmaline may have beneficial protective effects against reflux oesophagitis by the inhibition of gastric acid secretion, oxidative stress, inflammatory cytokine production (i.e. IL-1beta), and intracellular calcium mobilization in PMNs in rats.     

Effects of vitamin D on aortic smooth muscle cells in culture

Earlier investigations on vitamin-induced experimental atherosclerosis in rats suggested that smooth muscle cells (SMCs) play a pivotal role in development of these vascular abnormalities. This study demonstrates the effects of vitamin D (ergocalciferol) on SMCs of rat aorta in tissue culture. SMCs were obtained from aortas of newborn rats by enzymatic digestion and maintained for 6 wk in primary culture with vitamin D (1.2 n ) in the culture medium. The effects of vitamin D on SMCs, as compared with control SMCs cultures, were evaluated by light and electron microscopy. Growth of SMCs was characterized by cell counting, measurement of DNA and protein content, and by analysis of the nucleolar organizing regions. Vitamin D had no effect on proliferation of SMCs but stimulated synthesis and intercellular deposition of elastic fibres and had a stabilizing effect on the musculo-elastic multilayer formed by the cultured cells. In addition, it prevented degeneration of SMCs, with long-term preservation of the typical phenotype in primary culture.