[Protective effect of levothyroxine with oxidative stress reduction mechanism in ischemic preconditioning model in rat heart]

Background and Objective: A brief and short duration episode of ischemia is recorded in ischemic preconditioning [IPC]. This latter condition provides a status in which large region of heart is protected when prolonged ischemia occurred. Levothyroxine play a protective role in IPC induction, and simultaneously with stress oxidative. This study was conducted to determine the protective effect of levothyroxine with oxidative stress reduction mechanism in ischemic preconditioning model in rat heart

Methods: This experimental study was performed on 30 male Wistar rats in three groups of 10, as follows. In the reperfusion ischaemia group [IR], the heart of the animal was placed in a Langendorff apparatus. In the ischemic preconditioning group [IPC], prior to major ischemia, was exposed to 4 periods of 5-minute ischemia with reperfusion. In the intraperitoneally administered group, levothyroxine at a dose of 25 microgram per 100 g of body weight, the heart was exposed to reperfusion ischemia. The area of infarct and the level of malondialdehyde in the heart tissue were measured

Results: The volume of Infarcted region in IR and IPC groups was 26.55 and 11.11 respectively. The same index for the Levothyroxine receiver was 12.56. Based on these findings it was demonstrated that Levothyroxine injection reduced the Infarcted region significantly similar with IPC [P<0.05]. The MDA Levels in IR and IPC were 1328 and 777, respectively and in Levothyroxine group it was determined as 762. The size of Infarcted region in both IPC and treated with Levothyroxine groups significantly reduced in compared to IR group [P<0.05]

Conclusion: Injection of levothyroxine with ischemic preconditioning reduced the effect of reperfusion maladaptive ischemia in rat heart

[Role of adenosine on simvastatin protective effects in atrioventricular nodal properties in isolated atrial fibrillation model of rabbit heart]

The 3-hydroxy-3-methylglutaryl-coenzyme A [HMG-CoA] reductase inhibitors [statins] have revolutionized the treatment of hypercholesterolemia. Some evidence indicated the role of nodal refractoriness and concealed conduction in anticipating the ventricular rate during atrial fibrillation. Recent evidence has indicated that statins can reduce the incidence of both supraventricular and ventricular arrhythmias. The aim of the present study is to investigate adenosine A1 receptor role on simvastatin protective effects on atrioventricular nodal properties in isolated atrial fibrillation model of rabbit heart. The present study was performed in cardiovascular research center of Golestan University of Medical Sciences in 2012. Recovery and atrial fibrillation protocols were used to study electrophysiological properties of atrioventricular node in 5 groups of male Newsland rabbits [n=40]. Extracellular recording was carried out from transitional cells of posterior and anterior extension of AV-node and upper part of atrium and its bundle. All stimuli protocols repeated in the presence of adenosine A1 receptor agonist and antagonist [dipridamole and CPX] alone or with simvastatin on isolated perfused atrio-nodal preparation. Extracellular field potential recording was sampled during specific stimulation protocols. Significant inhibition was observed in basic node properties such as wenckebach prolongation, functional refractory period, effective refractory period and atrioventricular node conduction time with simvastatin [P<0.05]. Simvastatin prolonged His-His interval and increased number of concealed beat in atrial fibrillation protocol [P<0.05]. The simvastatin protective effects on atrioventricular nodal properties were intensified by dipridamole as an adenosine A1 receptor agonist [P<0.05], but CPX as an adenosine A1 receptor antagonist could only dampen them [P>0.05]. Our results showed that the use of adenosine agonist increased simvastatin effects on electrophysiological properties of atrioventricular node, but its antagonist could not prevent these effects. This may indicate simvastatin protective mechanism on atrioventricular node electrophysiological properties without adenosine direct involvement

Protective effect of urtica dioica L. [urticaeeae] on morphometric and morphologic alterations of seminiferous tubules in STZ diabetic rats

Urtica dioica L. has been known as a medicinal plant in the world. This study was conducted to determine the effects of the hydroalcoholic extract of Urtica dioica leaves on seminiferous tubules of diabetic rats. Animals were allocated to control, diabetic and protective groups. Treated animals received extract of U. dioica [100 mg/ kg/ day] IP for the first 5 days and STZ injection on the 6th day. After 5 weeks, testes removed and stained with H and E technique. Tubular cell disintegration, sertoli and spermatogonia cell vacuolization, and decrease in sperm concentration observed in diabetic in comparison with control and protective groups. External seminiferous tubular diameter and seminiferous epithelial height significantly reduced [P< 0.05] in diabetic compared with controls, and these parameters increased [P< 0.05] in the treated compared with diabetics. Hydroalcoholic extract of U. dioica, before induction of diabetes; has protective role on seminiferous tubules alterations

Prolongation of AV nodal refractoriness by Ruta graveolens in isolated rat hearts. Potenial role as an anti-arrhythmic agent

To evaluate concentration-dependent effects of total extract of Ruta graveolens and its purified alkaloid fraction on the nodal basic and functional properties. In the present experimental study, we used the Langendorff model for perfusion of isolated rat hearts to determine the effects of various concentrations of methanolic extract of Rue 1.25x10-6% weight per volume percent [W/V]; 2.5x10-6% W/V; 3.75x10-6% W/V and total alkaloid of Rue 0.25x10-6% W/V; 0.5x10-6% W/V on electrophysiological properties of cardiac tissue. Selective stimulation protocols were used to independently quantify atrioventricular AV nodal recovery, facilitation, and fatigue. We used 3 groups N=24 of isolated perfused rat AV nodal preparations to assess the effect of Rue extracts. The study was carried out in October 2006 in the electrophysiology laboratory of the Cardiovascular Research Center of Golestan University of Medical Sciences, Golestan, Gorgan, Iran. Our results showed that both the total plant extract and the alkaloid fraction of Ruta graveolens had a similar trend of action on nodal conduction time and refractoriness. Furthermore, we observed increased atrioventricular conduction time 83 +/- 4 to 108 +/- 5 msec and functional refractory period 157.6 +/- 3 to 163.7 +/- 4 msec at a maximum concentration of 3.75x10-6% W/V. The above results indicated a potential antiarrhythmic effect of Ruta graveolens in treating supra ventricular tachyarrhythmia

Effect of achiliea santolina on mice spermatogenesis

Achillea santolina, a common variety of Achillea in Golestan province of Iran has been used in traditional medicine for its anti-inflammatory properties. The effect of hydroalcoholic extract [300 mg/kg/day Intraperitoneally, for 20 days] of Achillea santolina on the spermatogenesis of mice was studied by the evaluation of morphologic characteristics by light microscope. The alterations observed were disorganized germ epithelium, exfoliation of immature germ cells, germ cell necrosis and increased number of metaphasfis in germinal epithelium of seminiferous tubules. We concluded that hydroalcoholic extract of Achillea santolina 300mg/kg/day intraperitoneally for 20 days as a different variety of Achillea has antispermatogenic effect similar to Achillea millefolium on mice