Nitric oxide and nitric oxide synthase isoforms in the normal, hypertrophic, and failing heart

Increased oxidative stress is one of the basic contributors to the development of the cardiovascular complications in diabetes. Both endothelial and vascular smooth muscle cell dysfunctions are the main sign involved in the pathogenesis of diabetic cardiovascular dysfunction. Matrix metalloproteinases (MMPs) are expressed in the vasculature, and participate in tissue remodeling under pathological conditions such as increased oxidative stress, whereas little is known about effect of hyperglycemia on regulation of MMPs in vascular system. Therefore, we aimed to evaluate the effect of an antioxidant, sodium selenate treatment (0.3 mg/kg for 4 weeks) on function of streptozotocin-diabetic rat aorta. Sodium selenate treatment improved significantly impaired isoproterenol-induced relaxation responses and contraction responses of the aortic strips, and exhibited marked protection against diabetes-induced degenerative changes in the smooth muscle cell morphology. Biochemical data showed that sodium selenate treatment induced a significant regulation of MMP-2 activity and protein loss as well as normalization of increased levels of tissue nitrite and protein thiol oxidation. In addition, this treatment restored diabetes-induced increased levels of endothelin-1, PKC, and cAMP production in the aortic tissue. Taken together, our data demonstrate that these beneficial effects of sodium selenate treatment in diabetics are related to be not only inhibition of increased oxidative stress but also prevention of both receptor- and smooth muscle-mediated dysfunction of vasculature, in part, via regulation of MMP-2. Such an observation provides evidence for potential therapeutic usage of selenium compounds for the amelioration of vascular disorders in diabetes.     

Nitric oxide in skeletal muscle: inhibition of nitric oxide synthase inhibits walking speed in rats.

Nitric oxide (NO*) is a multifunctional messenger molecule generated by a family of enzymes called the nitric oxide synthases (NOSs). Although NOSs have been identified in skeletal muscle, specifically brain NOS (bNOS) and endothelial NOS (eNOS), their role has not been well clarified. The goals of this investigation were to (1) characterize the immunoreactivity, Ca(2+) dependence, and activity of NOS in human and rat skeletal muscle and (2) using a rat model, investigate the effect of chronic blockade of NOS on skeletal muscle structure and function. Our results showed that both human and rodent skeletal muscle had NOS activity. This NOS activity was similar to that of the endothelial and brain NOS isoforms in that it was calcium-dependent. However, Western blot analysis consistently showed that a polyclonal antibody raised against a peptide sequence of human inducible NOS (iNOS) reacted with a protein with a molecular weight (95 kDa) that was different from that of other NOS isoforms. RT-PCR analysis identified the mRNA expression of not only eNOS and bNOS but also iNOS in human and rat muscle. Inhibition of nitric oxide synthase in rats with N(omega)-nitro-L-arginine methyl ester (L-NAME) resulted in a progressive, severe reduction in walking speed (30-fold reduction in walking velocity at day 22, P < 0.001), muscle fiber cross-sectional area (40% reduction at day 22, P < 0.001), and muscle mass (40% reduction in dry weight at day 22, P < 0.01). Rats fed the same regimen of the enantiomer of L-NAME (d-NAME) had normal motor function, muscle fiber morphology, and muscle mass. Taken together, these results imply that there may be a novel nitric oxide synthase in muscle and that NO. generated from muscle may be important in muscle function.     

Impaired protein quality control system underlies mitochondrial dysfunction in skeletal muscle of streptozotocin-induced diabetic rats

Hyperglycaemia-related mitochondrial impairment is suggested as a contributor to skeletal muscle dysfunction. Aiming a better understanding of the molecular mechanisms that underlie mitochondrial dysfunction in type 1 diabetic skeletal muscle, the role of the protein quality control system in mitochondria functionality was studied in intermyofibrillar mitochondria that were isolated from gastrocnemius muscle of streptozotocin (STZ)-induced diabetic rats. Hyperglycaemic rats showed more mitochondria but with lower ATP production ability, which was related with increased carbonylated protein levels and lower mitochondrial proteolytic activity assessed by zymography. LC-MS/MS analysis of the zymogram bands with proteolytic activity allowed the identification of an AAA protease, Lon protease; the metalloproteases PreP, LAP-3 and MIP; and cathepsin D. The content and activity of the Lon protease was lower in the STZ animals, as well as the expression of the m-AAA protease paraplegin, evaluated by western blotting. Data indicated that in muscle from diabetic rats the mitochondrial protein quality control system was compromised, which was evidenced by the decreased activity of AAA proteases, and was accompanied by the accumulation of oxidatively modified proteins, thereby causing adverse effects on mitochondrial functionality.     

Comparison of the liver glycogen synthase from normal and streptozotocin-induced diabetic rats

Glycogen synthase in the liver extracts of short-term (3 days) streptozotocin-induced diabetic rats is poorly activated by the endogenous synthase phosphatase as well as phosphatase(s) from the liver extracts of normal animals. However, synthase in the liver extracts of diabetic rats is readily activated by the 35,000 M_r rabbit liver protein phosphatase (H. Brandt, F. L. Capulong, and E. Y. C. Lee (J. Biol. Chem.250, 8038–8044 (1975)). The purified synthases from normal and diabetic animals respond differently after incubations with three different phosphatases. Both normal and diabetic synthase are activated by the 35,000 M_r protein phosphatase; however, the total activity of diabetic, but not the normal, synthase is significantly increased. Normal, but not the diabetic, synthase is activated by a synthase phosphatase from normal rats; this activation is accompanied by an increase in total synthase activity. Incubation of the diabetic synthase with calf intestinal alkaline phosphatase results in a reduction of the total synthase activity, whereas synthase activity of the normal is not significantly affected. The reduction in total activity of the diabetic synthase by treatment with alkaline phosphatase was prevented by prior dephosphorylation with 35,000 M_r rabbit liver protein phosphatase. In addition to their differences in responses to different phosphatases, the normal and diabetic synthases are also different in their molecular weights as determined by sucrose density gradient centrifugation (154,000 ± 17,000 (n = 6) for the normal and 185,000 ± 15,000 (n = 8) for the diabetic synthase) and their kinetic properties.     

Nitric oxide synthase (NOS) in mouse skeletal muscle development and differentiated myoblasts

The neuronal isoform of nitric oxide synthase (nNOS, termed also NOS-I) is expressed in normal adult skeletal muscle, suggesting important functions for NO in muscle biology. However, the expression and subcellular localization of NOS in muscle development and myoblast differentiation are largely unknown. In the present study, NOS was immunolocalized with isoform-specific antibodies in developing muscle and in differentiated myoblast cultures (mouse C2C12) together with histochemical NADPH-dependent diaphorase activity that is blocked by specific NOS inhibitors and therefore designated as NOS-associated diaphorase activity (NOSaD). Western blot analysis revealed immunoreactive bands for NOS-I-III in lysates from perinatal and adult muscle tissue and C2C12-myotubes that comigrated with prototypical proteins. In embryonic skeletal muscle, but not in adult myofibers, diffuse cytosolic staining and lack of sarcolemmal NOSaD activity and NOS-I immunoreaction were evident. In both myoblasts and fusioned myotubes, NOSaD and NOS isoforms I-III colocalize in the cytosol. Additionally, members of the sarcolemmal dystrophin-glycoprotein complex (i.e., dystrophin, adhalin, β1-dystroglycan) immunolocalize in the cytosol of differentiating myoblasts, whereas anti-dystrophin and anti-β1-dystroglycan clearly delineate the sarcolemma in myotubes. Thus, expression of NOS isoforms I-III and NOSaD is cytosolic in fusion-competent myoblasts during myotube formation in vitro. Interaction of NOSaD/NOS-I with the sarcolemmal dystrophin-complex known from mature myofibers is apparently lacking in prenatal muscle development and differentiating myoblasts. Localization of NOS isoforms thus characterized in myogenic cultures may help further to investigate regulated NO formation in muscle cells in vitro.     

Decreased activity and impaired induction of nitric oxide synthase by lipopolysaccharides in streptozotocin-induced diabetic rats

The effect of diabetes was determined on nitric oxide synthase (NOS) activity in rat heart and liver. The diabetes was induced by streptozotocin (STZ) and NOS activity was determined after 1 or 12 weeks post-STZ injection. In both tissues, the majority of NOS activity was associated with endothelial constitutive calcium-sensitive NOS (ecNOS) isoform and found in the particulate (100,000xg pellet) fraction in young rats. The diabetes as well as age reduced this activity significantly in heart, whereas only the age caused a decrease in ecNOS activity in liver tissue. Lipopolysaccharides (LPS) induced calcium-insensitive iNOS activity in both young and old rats. The induction was significantly higher (up to 10-fold) in liver as compared to heart. Although the maximum induction of iNOS in young rats was almost similar in diabetic tissues as compared to control animals, there was a lag period for induction of iNOS in diabetic tissues. In old diabetic rats, the induction by LPS was almost completely abolished. These results suggest that diabetes causes either no change or a decrease in ecNOS activity and impairment in the induction of iNOS by LPS in rat heart and liver.     

Expression of GLUT4 glucose transporter protein in adipose tissue and skeletal muscle from streptozotocin-induced diabetic pregnant rats.

Depletion of GLUT4, the primary glucose transporter protein in adipose tissue and skeletal muscle, is reported to contribute to insulin resistance in pregnancy or diabetes. To examine this phenomenon, the expression of GLUT4 protein was assessed by Western blotting in streptozotocin-induced diabetic pregnant rats. In adipose tissue, relative to control, it was decreased by 30% in the normal pregnant group (p<0.001), by 37% in the diabetic nonpregnant group (p<0.01) and by 65% in the diabetic pregnant group (p<0.001). On the other hand, no significant variation was evident among the groups in skeletal muscle. To assess the mechanisms responsible for depletion of GLUT4 protein in adipose tissue, we quantitated levels of GLUT4 mRNA with a RNase protection assay. It was decreased by 44% in the normal pregnant group (p<0.05) and by 55% in the diabetic pregnant group (p<0.05), but not altered in the diabetic nonpregnant group. These results suggest that the depletion of GLUT4 protein in adipose tissue is a factor contributing to insulin resistance in pregnancy or diabetes, especially when the two states exist in combination.     

Expression of basic fibroblast growth factor,protein kinase C and members of the apoptotic pathway in skeletal muscle of streptozotocin-induced diabetic rats

This study investigated the potential mechanisms that may underlie diabetes induced amyoatrophy. Sprague-Dawley rats were either injected intraperiotneally with STZ (test group; N = 8) to induce diabetic-like symptoms (blood glucose level ≥16.65 mmol/L) or with buffer (control group; N = 8). Differences in muscle structure between the STZ-induced diabetic and control groups were evaluated by histochemistry. Protein and mRNA levels of basic FGF (bFGF), bax, bcl-2, and caspase 3 in skeletal muscle were compared between the 2 groups using immunohistochemistry and quantitative PCR, respectively. Serum level of insulin and protein kinase C (PKC) were measured by competitive RIA and ELISA, respectively. Unlike control animals, the skeletal muscle fibers from STZ-induced diabetic animals were broken and pyknotic, the sarcomeric structure disrupted, and mild hyperplasia of interstitial adipose tissues was detected. The serum level of PKC was higher (P = 0.003) and the protein and mRNA levels of bFGF in skeletal muscle were lower (P = 0.001) in STZ-induced diabetic versus control animals. Protein and mRNA levels of the apoptosis promoting genes caspase-3 and bax were higher in skeletal muscle from STZ-induced diabetic rats as compared to control animals (P < 0.001 and P = 0.037, respectively), while mRNA and protein levels of bcl-2, an inhibitor of apoptosis, was lower in STZ-induced diabetic rats versus control animals (P = 0.026). Increasing apoptosis in skeletal muscle from STZ-induced diabetic rats was further demonstrated by TNNEL assay. Our findings suggest that enhanced PKC levels, reduction of bFGF expression, and increased in apoptosis might be associated with the development of diabetes-induced myoatrophy.     

Hypoglycemic activity of a polyphenolic oligomer-rich extract of Cinnamomum parthenoxylon bark in normal and streptozotocin-induced diabetic rats

Cinnamon bark has been reported to be effective in the alleviation of diabetes through its antioxidant and insulin-potentiating activities. The water-soluble polyphenolic oligomers found in cinnamon are thought to be responsible for this biological activity. In this study, the hypoglycemic activity of a polyphenolic oligomer-rich extract from the barks of Cinnamomum parthenoxylon (Jack) Nees was studied in normal, transiently hyperglycemic, and streptozotocin (STZ)-induced diabetic rats. Oral administration of the extract at doses of 100, 200, and 300 mg/kg body wt. caused significant changes in body weight loss and fasting blood glucose levels of normal rats. In STZ-induced diabetic rats, after administration of the extract at doses of 100, 200, and 300 mg/kg body wt. over 14 days, the blood glucose levels were decreased by 11.1%, 22.5%, and 38.7%, respectively, and the plasma insulin levels were significantly increased over pre-treatment levels. In an oral glucose tolerance test, the extract produced a significant decrease in glycemia 90 min after the glucose pulse. These results suggest that Cinnamomum parthenoxylon polyphenolic oligomer-rich extract could be potentially useful for post-prandial hyperglycemia treatment.     

Interactions between oxytocin, glucagon and glucose in normal and streptozotocin-induced diabetic rats

Oxytocin has been suggested to have glucoregulatory functions in rats, man and other mammals. The hyperglycemic actions of oxytocin are believed to be mediated indirectly through changes in pancreatic function. The present study examined the interaction between glucose and oxytocin in normal and streptozotocin (STZ)-induced diabetic rats, under basal conditions and after injections of oxytocin. Plasma glucose and endogenous oxytocin levels were significantly correlated in cannulated lactating rats (r = 0.44, P less than 0.01). To test the hypothesis that oxytocin was acting to elevate plasma glucose, adult male rats were injected with 10 micrograms/kg oxytocin and killed 60 min later. Oxytocin increased plasma glucose from 6.1 +/- 0.1 to 6.8 +/- 0.2 mM (P less than 0.05), and glucagon from 179 +/- 12 to 259 +/- 32 pg/ml (P less than 0.01, n = 18). There was no significant effect of oxytocin on plasma insulin, although the levels were increased by 30%. A lower dose (1 microgram/kg) of oxytocin had no significant effect on plasma glucose or glucagon. To eliminate putative local inhibitory effects of insulin on glucagon secretion, male rats were made diabetic by i.p. injection of 100 mg/kg STZ, which increased glucose to greater than 18 mM and glucagon to 249 +/- 25 pg/ml (P less than 0.05). In these rats, 10 micrograms/kg oxytocin failed to further increase plasma glucose, but caused a much greater increase in glucagon (to 828 +/- 248 pg/ml) and also increased plasma ACTH. A specific oxytocin analog, Thr4,Gly7-oxytocin, mimicked the effect of oxytocin on glucagon secretion in diabetic rats. The lower dose of oxytocin also increased glucagon levels (to 1300 +/- 250 pg/ml), but the effect was not significant. A 3 h i.v. infusion of 1 nmol/kg per h oxytocin in conscious male rats significantly increased glucagon levels by 30 min in normal and STZ-rats; levels returned to baseline by 30 min after stopping the infusion. Plasma glucose increased in the normal, but not STZ-rats. The relative magnitude of the increase in glucagon was identical for normal and diabetic rats, but the absolute levels of glucagon during the infusion were twice as high in the diabetics. To test whether hypoglycemia could elevate plasma levels of oxytocin, male rats were injected i.p. with insulin and killed from 15-180 min later. Plasma glucose levels dropped to less than 2.5 mM by 15 min. Oxytocin levels increased by 150-200% at 30 min; however, the effect was not statistically significant.(ABSTRACT TRUNCATED AT 400 WORDS)     

Nitric oxide synthase (NOS) coexists with activated neurons by skeletal muscle contraction in the brainstem of cats

Contraction of skeletal muscle evokes increases in arterial blood pressure and heart rate. Some regions of the brainstem have been implicated for expression of the cardiovascular responses to muscle contraction. Previous studies have reported that static muscle contraction induced c-Fos protein in the nucleus of tractus solitarii (NTS), lateral reticular nucleus (LRN), lateral tegmental field (FTL), subretrofacial nucleus (SRF), A1 region and periaqueductal gray (PAG) of the brainstem. Furthermore, neuronal NADPH-diaphorase (NADPH-d), which is considered as a marker of neuronal nitric oxide synthase (nNOS), has been localized in those same regions. In this study, static muscle contraction was induced by electrical stimulation of the L7 and S1 ventral roots in anaesthetized cats. Distribution of c-Fos protein within neurons containing nNOS was evaluated by double labeling methods in order to determine if nNOS containing neurons in the brainstem were activated during muscle contraction. The results indicate that c-Fos protein colocalized with NADPH-d positive staining within the neurons of the SRF and PAG, but not within the NTS neurons. Distinct number of neurons with c-Fos protein was in close proximity to NADPH-d positive staining in the NTS, SRF, and PAG. Coexisting of c-Fos protein and NADPH-d positive staining was not observed in the LRN, FTL and A1 region. These findings demonstrate that nNOS containing neurons were activated by muscle contraction in the selective regions of the brainstem, and nNOS positive staining had close anatomic contacts with the neurons activated by contraction. This result provides neuroanatomic evidence suggesting that nitric oxide modulates the cardiovascular responses to muscle contraction within the NTS, SRF and PAG of the brainstem.     

Effects of coenzyme Q10 treatment on antioxidant pathways in normal and streptozotocin-induced diabetic rats

Coenzyme Q10 is an endogenous lipid soluble antioxidant. Because oxidant stress may exacerbate some complications of diabetes mellitus, this study investigated the effects of subacute treatment with exogenous coenzyme Q10 (10 mg/kg/day, i.p. for 14 days) on tissue antioxidant defenses in 30-day streptozotocin-induced diabetic Sprague-Dawley rats. Liver, kidney, brain, and heart were assayed for degree of lipid peroxidation, reduced and oxidized glutathione contents, and activities of catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase. All tissues from diabetic animals exhibited increased oxidative stress and disturbances in antioxidant defense when compared with normal controls. Treatment with the lipophilic compound coenzyme Q10 reversed diabetic effects on hepatic glutathione peroxidase activity, on renal superoxide dismutase activity, on cardiac lipid peroxidation, and on oxidized glutathione concentration in brain. However, treatment with coenzyme Q10 also exacerbated the increase in cardiac catalase activity, which was already elevated by diabetes, further decreased hepatic glutathione reductase activity, augmented the increase in hepatic lipid peroxidation, and further increased glutathione peroxidase activity in the heart and brain of diabetic animals. Subacute dosing with coenzyme Q10 ameliorated some of the diabetes-induced changes in oxidative stress. However, exacerbation of several diabetes-related effects was also observed.     

Comparison of hematologic parameters in normal and streptozotocin-induced diabetic rats.

Hematologic values are compared for normal and streptozotocin-induced diabetic rats after 6 weeks of induced diabetes. Most hematologic parameters were the same in the two groups except for blood glucose, glycated hemoglobin, and 2,3 diphosphoglycerate, all of which were elevated in the streptozotocin group. However the P50 (the PO2 at which the oxygen-carrying capacity of blood is 50% of maximal) remained normal. We hypothesize that a left shift in the oxyhemoglobin dissociation curve caused by the glycation of a small percentage of the hemoglobin is compensated by elevation in the 2,3-diphosphoglycerate which returns the P50 to normal values. This compensatory mechanism also occurs in some stages of human diabetes.     

Expression of nitric oxide synthase isoforms in normal ventilatory and limb muscles

Hussain, Sabah N. A., Qasim El-Dwairi, Mohammed N. Abdul-Hussain, and Dalia Sakkal. Expression of nitric oxidesynthase isoforms in normal ventilatory and limb muscles.J. Appl. Physiol. 83(2): 348-353, 1997.Nitric oxide (NO), an important messenger molecule withwidespread actions, is synthesized by NO synthases (NOS). In thisstudy, we investigated the correlation between fiber type and NOSactivity among ventilatory and limb muscles of various species. We alsoassessed the presence of the three NOS isoforms in normal skeletalmuscles and how various NOS inhibitors influence muscle NOS activity.NOS activity was detected in various muscles; however, NOS activity inrabbits and rats varied significantly among different muscles.Immunoblotting of muscle samples indicated the presence of both theneuronal NOS and the endothelial NOS isoforms but not thecytokine-inducible NOS isoform. However, these isoforms were expressedto different degrees in various muscles. Although the neuronal NOSisoform was detectable in the canine diaphragm, very weak expressionwas detected in rabbit, rat, and mouse diaphragms. The endothelial NOSisoform was detected in the rat and mouse diaphragms but not in thecanine and rabbit diaphragms. We also found thatN^G-nitro-L-arginine methyl ester,7-nitroindazole, andS-methylisothiourea werestronger inhibitors of muscle NOS activity than was aminoguanidine. These results indicate the presence of different degrees ofconstitutive NOS expression in normal ventilatory and limb muscles ofvarious species. Our data also indicate that muscle NOS activity is not determined by fiber type distribution but by other not yet identified factors. The functional significance of this expression remains to beassessed.

     

Beneficial effects of Phellodendri Cortex extract on hyperglycemia and diabetic nephropathy in streptozotocin-induced diabetic rats

This study investigated the effect of Phellodendri Cortex extract on hyperglycemia and diabetic nephropathy in streptozotocin-induced diabetic rats. Male Sprague-Dawley rats were divided into normal control (NC), diabetic control (DC), and diabetic treatment with Phellodendri Cortex extract (DP). Over a 4-week experimental period, Phellodendri Cortex extract was administered orally at 379 mg/kg BW/day. The final fasting serum glucose level, urine total protein level, and relative left kidney weight in the DP group were significantly lower than the DC group. Renal XO and SOD activities in the DP group were significantly lower than the DC group and renal CAT activity in the DP group was significantly higher than the DC group. Tubular epithelial change was reduced in the DP group compared to the DC group. These results indicated that Phellodendri Cortex can reduce glucose level and prevent or retard the development of diabetic nephropathy in streptozotocin-induced diabetic rats.     

Antiperoxidative and antioxidant effects of Casearia esculenta root extract in streptozotocin-induced diabetic rats

Oxidative stress is currently suggested to play as a pathogenesis in the development of diabetes mellitus. The present study was designed to evaluate the effect of Casearia esculenta root extract on oxidative stress-related parameters in streptozotocin (STZ) -induced diabetic rats. Antidiabetic treatment with C. esculenta root extract (45 days) significantly (p < .05) decreased thiobarbituric acid reactive substances (TBARS) and remarkably improved tissue antioxidants status such as glutathione (GSH), ascorbic acid (vitamin C) and alpha-tocopherol (vitamin E) in liver and kidney of STZ-diabetic rats. In diabetics rats, the activities of enzymatic antioxidants such as superoxide dismutase (SOD, EC 1.11.1.1) catalase (CAT, EC 1.11.1.6) were decreased significantly while the activity of glutathione peroxidase (GPx, EC 1.11.1.9) decreased in the liver and increased in the kidney. The treatment of diabetic rats with C. esculenta root extract over a 45-day period returned these levels close to normal. These results suggest that C. esculenta root extracts exhibit antiperoxidative as well as antioxidant effects in STZ-induced diabetic rats.     

银杏叶提取物猴头菌转化前后降血糖作用的比较研究

The regulatory effects of blood glucose, lipid metabolism and free radical elimination were compared in streptozotocin-induced hyperglycemic rats among the following treatments: Ginkgo biloba leaf extract (EGB), the biotransformation of EGB by Hericium erinaceus, a cultural filtrate of H.erinaceus, and the cultural filtrate of H.erinaceus plus EGB, together with the normal control, the model control and the positive control (Metformin). The best results were obtained from the biotransformation treatment group, which could significantly reduce the levels of blood glucose and fructosamine. However, the treatment did not increase the blood insulin level. The EGB transformed products could obviously increase the serum superoxide dismutase activity and reduce the malondialdehyde level, but the reduction of malondialdehyde was not obvious as compared with that of the other treatment groups. This study provides a useful information on improving the medical properties of the herb extracts by biotransformation.     

银杏叶提取物猴头菌转化前后降血糖作用的比较研究

以正常对照组、模型对照组和阳性(二甲双胍)对照组为参照,试验比较了银杏叶提取物(EGB)、猴头菌转化EGB的产物、猴头菌发酵液、猴头菌发酵液中添加EGB对链脲佐菌素诱导的2型糖尿病模型大鼠血糖和血脂代谢的调节作用以及对自由基清除作用。结果显示:相对于其他给药组,猴头菌转化EGB的转化产物能更加显著地降低糖尿病模型大鼠的血糖和果糖胺水平,但是对胰岛素水平无显著的调节作用,与模型对照组和其他给药组相比,EGB转化产物可以显著提高超氧化物岐化酶活性;与模型对照组相比亦可显著降低丙二醛水平,但与其他给药组相比其降丙二醛作用差异不明显。本项研究对采用微生物转化法提高植物提取物药用效果提供了参考资料。