Scaffolds provide a three-dimensional environment that is desirable for inducing and promoting the production of cartilaginous tissue.Ideally the scaffold should:① have directed and controlled degradation;② promote cell viability,differentiation,and extracellular matrix production;③ adhere and integrate with the surrounding native cartilage;④ span and assume the size of the defect;⑤ provide mechanical integrity depending on the defect location;⑥ have no toxicity,no immunogenicity or inflammatory induction;⑦ allow for the diffusion of nutrients and waste products.To date,a wide range of natural and synthetic materials have been investigated as a scaffold for cartilage repair.Based on the morphology and structure,these materials can be divided into hydrogel,sponge,fiber mesh and so on.Natural polymers that have been explored as bioactive scaffolds for cartilage engineering include:alginate,agarose,fibrin,hyaluronic acid,collagen,gelatin,chitosan,chondroitin sulfate,and cellulose.Synthetic polymers currently explored for cartilage repair include poly(?-hydroxy esters),polyethylene glycol,poly(NiPAAm),poly(propylene fumarates),and polyurethanes.

Stimulating factors have been employed to induce,accelerate,and/or enhance cartilage formation.For instance,stimulating factors and other additives may be added to culture media in vitro or incorporated into scaffolds for in vivo delivery to control cellular differentiation and tissue formation.At present,many growth factors and other dissoluble factors such as hyaluronic acid,chondroitin sulfate,and insulin have been used alone or synergistically in cartilage tissue engineering.The application efficacy depends on cell type and culture condition.In addition,gene therapy has emerged as another method of local delivery,where cells can be engineered to over-express bioactive molecules.An additional approach is the introduction of mechanical signals through loading regimes such as hydrostatic or dynamic compression or through the use of bioreactors.Current bioreactors used in cartilage tissue engineering include flat-sheet bioreactor,rotating wall vessel bioreactor and concentric cylinder bioreactor.Bioreactor can improve nutrition transmittability,provide hydrodynamic environment,induce shear stress,and promote production of cartilage specific matrix protein.

AIM: To study apoptosis and related genes expressions of cardiomyocytes in sinoaortic-denervated(SAD) rats. METHODS: SAD or sham-operation (Sham) was performed in male SD rats at the age of 10 weeks. After 16 weeks, apoptotic cells were stained in situ by terminal dexynucleotidyl-transferase mediated-dUTP nick end labeling (TUNEL). All stained results were analysised using computer image analysis techniques. Protein products and mRNA of Bcl-2, Bax, Fas and Fas-L were assessed by quantitative immunohistochemistry and RT-PCR. RESULTS: The numbers of apoptotic cardiomyocytes were significantly increased in SAD rats, the expressions of Bcl-2 were significantly decreased, whereas Bax,Fas and Fas-L were significantly increased in SAD rats. THZ]CONCLUSIONCONCLUSION: Apoptosis and dysregulation of gene expressions may be involved in the cardiomyocytes remodeling in SAD rats.

40 weeks old SHR did not differ from that in slices of age matched WKY. B max was increased in the same brain region of SHR when compared to WKY. That rats of 4 5 weeks were in prehypertensive stage;rats of 10 12 weeks and above were at the stage of establishing hypertensive stage. Conclusion: The difference between SHR and normotensive rats in 5 HT 1A receptor binding in various brain regions may be related to the development of hypertension. When blood pressure changes,binding capacity of 5 HT 1A receptor in CNS changes accordingly.

Objective:Glucose-insulin-potassium(GIK) is clinically used for reducing mortality in acute myocardial infarction(MI). It is known that ventricular arrhythmia, left ventricular dysfunction and impaired baroreflex sensitivity(BRS) are the three major determinants for predicting the mortality after acute MI. The present work was designed to study the effects of GIK on BRS, ventricular arrhythmia, and left ventricular function in rats with coronary artery ligature. Sprague-Dawley rats were used and the myocardial infarction was produced by ligature of the left anterior descending artery. Five weeks after coronary artery ligation, BRS was measured in conscious state with a computerized blood pressure monitoring system and left ventricular function and electrocardiogram were determined in the anaesthetized state in the subacute phase of myocardial infarction. It was found that GIK did not affect the blood pressure and heart period in both conscious and anaesthetized rats. GIK did not enhance BRS, but reduced ventricular arrhythmia and improved left ventricular function by reducing left ventricular end diastolic pressure in anaesthetized rats with MI. It is proposed that reducing ventricular arrhythmia and improving left ventricular function contribute to the effect of GIK on reducing the mortality after MI.

Objective:It has been proposed that blood pressure variability(BPV) is positively related to end-organ damage(EOD) in hypertension.The present work was designed to observe the effects of long-term treatment with nitrendipine and hydralazine on BPV and EOD in spontaneously hypertensive rats(SHR),to examine the hypothesis that lowering BPV with an antihypertensive drug is an important factor in organ protection.Design and methods:Drugs were mixed in rat chow.After 4 months of drug administration,blood pressure was recorded continuously in conscious freely moving rats for 24 h.The heart,kidneys,and brain were then isolated and examined.Results:It was found that nitrendipine significantly decreased blood pressure and BPV,and significantly decreased EOD score in SHR.Hydralazine decreased blood pressure,but did not lower BPV.No effect on EOD was found in hydralazine-treated rats.In control rat(n=38),EOD score was weakly related to systolic blood pressure(r=0.331,P<0.05) and closely related to long-term systolic BPV(r=0.551,P<0.01).In nitrendipine-treated rats,EOD score was closely related to long-term systolic BPV(r=0.602,P<0.01),but not to blood pressure level(r=0.174,P>0.05).Conclusion:BPV plays an important role in the organ-protecting effects of nitrendipine.

Objective:To investigate the protective effect of Intravenous Injection of Radix Astragali seu Hedysari on acute myocardiac infarction (AMI) in anesthetized dogs. Methods: Twenty health dogs were treated by ligating descending anterior of coronary with two-step method. The changes of electrocardiogram before and after ligation were recorded. After 4 hours myocardium were taken out and dyed with NBT to make sure of the extent of myocardiac infarction.Results: Intravenous Injection of Radix Astragali seu Hedysari could decrease the lethality of AMI, ameliorated ST changes on electrocardiogram induced by AMI, and reduced infarction area. Conclusions: Intravenous Injection of Radix Astragali seu Hedysari is effective in the treatment of AMI in anesthetized dogs.

Objective:Clonidine,by activating peripheral α-sbrenoceptors, produces transient pressor response after i.v.injection in anesthetized animals.Moxonidine, with at least 40-fold higher affinity to I1-imidazoline receptors than to α2-adrenoceptors,produces also a transient pressor response. This work was designed to investigate whether I1-imidazoline receptors are involved in this pressor effect of moxonidine. Methods:Female spontaneously hypertensive rats(SHRs,aged 14-16 weeks)were anesthetized with urethane.To observe the transient pressor responses,moxonidine 0.1,0.3,1.0mg/kg(intravenous,i.v),2.0μg(intracerebroventricular,i.c.v.)and 1.0,10.0mg/kg(intragastric,i.g.)were administrated in different groups of rats.To evaluate the roles of α1-adrenoceptors,α2-adrenoceptors and I1-imidazoline receptors in the transient pressor responses to moxonidine, prazosin(10.0μg/kg),yohimbine(2.0mg/kg),phentolamine(0.2mg/kg),idazoxan(1.0mg/kg)or yohimbine+idazoxan(2.0mg/kg+1.0mg/kg)were intravenously given to the animals before moxonidine 0.3mg/kg (i.v.).Results:It was found that i.v.moxonidine produced a greater pressor response than clonidine when producing a similar reduction of blood pressure.This effect of moxonidine was not influenced by prazosin, but was partly inhibited by yohimbine, phentolamine or idazoxan,and completely blocked by the combination of yohimbine and idzaxon.Neither i.c.v.injection nor i.g. administration of moxonidine induced transient pressor responses.Conclusion:The transient pressor response of i.v. moxonidine is mediated by both peripheral I1-imidazoline receptors and α2-adrenoceptors.

Objective To determine the effects of trimetazidine (TMZ) on pathology and energy metabolism of myocardium in chronic renal failure(CRF) rats.Methods CRF models were built in Sprague-Dawley (SD) rats with 5/6 subtotal nephrectomy, and animals were randomyly divided into sham group, control group and three groups treated with different doses of TMZ (3 mg/kg,6 mg/kg or 9 mg/kg).TMZ was intragastrically administrated to CRF rats for 17 weeks, while physiologicalsalinewasusedascontrol. Transthoracicechocardiographywasperformedand myocardial morphosis was observed.Left ventricular weight/body weight(LVW/BW) and heart weight/body weight (HW/BW) were measured, and heart rate, and mean arterial pressure (MAP)were detected at the end of the study, while several parameters were detected, including urea nitrogen (BUN), creatinine(Scr), triphosaden(ATP), adenosine diphosphate(ADP), superoxide dismutase (SOD), malondialdehyde (MDA), interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α).Results (l)Left ventricle end-systolic dimensions, anterior wall end-diastolic and end-systolic thicknesses, and posterior wall end-diastolic thickness were significantly lower in rats treated with either medium dose or high dose of TMZ, as compared with control group(P＜0.05).(2)LVW/BW and HW/BW in rats treated with either medium dose or high dose of TMZ were significantly lower than those in control group(P＜0.05). (3)Various pathological changes were observed in control group, such as irregular arrangement and hypertrophy of the cardiomyocytes, myocardial fibrosis,mitochondrial swelling, focal muscle fiber dissolution, etc.However, all these pathological changes were apparently ameliorated in TMZ-treated groups, while the beneficial effects of TMZ therapy were dose-dependent. (4)No difference was observed in heart rate among all the groups.Although no difference existed in all the CRF rats, concerning on the systolic/diastolic blood pressure and mean arterial pressure (P＞0.05), these parameters were elevated in CRF rats, as compared with sham-operated group(P＜0.01). (5)ATP and ADP in TMZ-treated rats were significantly higher as compared with control(P＜0.05), moreover, medium dose and high dose of TMZ were superior to low dose (P＜0.05).(6)SOD was significantly increased in TMZ-treated rats (P＜0.05), while IL-6,TNF-α and MDA were significantly decreased in medium dose and high dose of TMZ, as compared with control(P＜0.05).Conclusion TMZ may prevent myocardial fibrosis and left ventricular hypertrophy in chronic renal failure via ameliorating myocardial energy metabolism and alleviating inflammatory reaction and oxidative stress.