scholarly journals Effect of Reoxygenation on the Electrical Stability of the Rat Heart In Vivo: A Chronobiological Study

2013 ◽  
pp. S143-S149
Author(s):  
P. ŠVORC ◽  
A. MAROSSY ◽  
P. ŠVORC ◽  
M. BUŽGA

Reoxygenation following hypoxic episodes can increase the risk for the development of ventricular arrhythmias, which, in addition to circadian aspects of reoxygenation arrhythmias has not been studied extensively. The aim of the present study was to evaluate circadian changes in the electrical stability of the rat heart during reoxygenation following a hypoventilatory episode. The electrical stability of the heart, defined in the present study as the ventricular arrhythmia threshold (VAT), was measured at 3 h intervals at clock times 09:00, 12:00, 15:00, 18:00, 21:00, 24:00, 03:00, 06:00 and 09:00 during 20 min hypoventilation (20 breaths/min, tidal volume = 0.5 ml/100 g body weight [n=17]) and subsequent 20 min reoxygenation (50 breaths/min, tidal volume = 1 ml/100 g body weight [n=4]) intervals. The experiments were performed using pentobarbital-anesthetized (40 mg/kg intraperitoneally) female Wistar rats that first underwent a four-week adaptation to a 12 h light:12 h dark regimen. Detailed analysis showed that circadian VATs changed to biphasic rhythms at 10 min of hypoventilation. The VAT circadian rhythms were observed immediately following the commencement of reoxygenation, with the highest values measured between 12:00 and 15:00, and the lowest values between 24:00 and 03:00. These results suggest that myocardial vulnerability is dependent on the light:dark cycle and characteristics of pulmonary ventilation.

2010 ◽  
Vol 58 (3) ◽  
pp. 171-176 ◽  
Author(s):  
Roland Pálffy ◽  
Michal Behuliak ◽  
Roman Gardlík ◽  
Peter Jáni ◽  
L'udevít Kádaši ◽  
...  

2012 ◽  
Vol 46 (2) ◽  
pp. 101-107 ◽  
Author(s):  
M Moraal ◽  
P P A M Leenaars ◽  
H Arnts ◽  
K Smeets ◽  
B S Savenije ◽  
...  

Ad libitum (AL) supply of standard chow is the feeding method most often used for rodents in animal experiments. However, AL feeding is known to result in a shorter lifespan and decreased health as compared with restricted feeding. Restricted feeding and thus limiting calorie intake prevents many health problems, increases lifespan and can also increase group uniformity. All this leads to a reduced number of animals needed. So-called standard chows are known to be prone to variation in composition. Synthetic foods have a more standard composition, contributing to group uniformity which, like diet reduction, may decrease the number of animals necessary to obtain statistical significance. In this study, we compared the effects of AL versus restricted feeding (25% reduction in food intake) on standard chow versus synthetic food of three different suppliers on body weight (BW), growth, several blood parameters and organ weights in growing female Wistar rats over a period of 61 days. Diet restriction led to a decreased growth and significantly reduced variation in BW and growth as compared with AL feeding. AL feeding on synthetic diets caused a significantly higher BW gain than on chow diets. Due to experimental design, this same effect occurred on food restriction. Blood parameters and organ weights were affected neither by diet type nor by amount. Incidentally, variations were significantly reduced on food restriction versus AL, and on synthetic diets versus chow diets. This study demonstrates that food restriction versus AL feeding leads to a significantly reduced variation in BW and growth, thereby indicating the potential for reduction when applying this feeding schedule.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jyoti Kaushik ◽  
Simran Tandon ◽  
Rishi Bhardwaj ◽  
Tanzeer Kaur ◽  
Surinder Kumar Singla ◽  
...  

Abstract Modern treatment interventions for kidney stones are wrought with side-effects, hence the need for alternative therapies such as plant-based medicines. We have previously documented through in vitro studies that statistically optimized aqueous extract of Tribulus terrestris (Zygophyllaceae family) possesses antiurolithic and antioxidant potential. This provides strong scientific foundation to conduct in vivo efficacy and preclinical safety studies to corroborate and lend further proof to its ability to prevent and cure kidney stones. The preventive and curative urolithiatic efficacy in experimentally induced nephrolithiatic Wistar rats, along with preclinical toxicity was evaluated following oral administration of statistically optimized aqueous extract of T. terrestris. Treatment showed augmented renal function, restoration of normal renal architecture and increase in body weight. Microscopic analysis of urine revealed excretion of small sized urinary crystals, demonstrating that treatment potentially modulated the morphology of renal stones. Tissue enzymatic estimation affirmed the antioxidant efficacy of treatment with reduced free radical generation. Significant upregulation of p38MAPK at both the gene and protein level was noted in hyperoxaluric group and interestingly treatment reversed it. Acute oral toxicity study established the Median Lethal Dose (LD50) to be greater than 2000 mg/kg body weight (b.wt.) No observed adverse effect level (NOAEL) by repeated oral toxicity for 28 days at 750 mg/kg b.wt. was noted. This study lends scientific evidence to the safe, preventive and curative potential of statistically optimized aqueous extract of T. terrestris at a dose of 750 mg/kg b.wt. and suggests that the extract shows promise as a therapeutic antiurolithic agent.


2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
C. P. Ekanayake ◽  
M. G. Thammitiyagodage ◽  
S. Padumadasa ◽  
B. Seneviratne ◽  
C. Padumadasa ◽  
...  

Ayurvedic and traditional medical practitioners of Sri Lanka use the decoction of the immature inflorescence of Cocos nucifera L. (IC) variety aurantiaca for the treatment of menorrhagia. The progestogenic effect of the ethyl acetate soluble proanthocyanidins (EASPA) of the IC in female rats at a dose of 3.5 mg/kg body weight has been reported. Acute and subacute toxicity studies of EASPA of the IC carried out using female Wistar rats according to Organization for Economic Co-operation and Development (OECD) guidelines 423 and 407, respectively, are reported herein. In the acute toxicity study, a single dose of EASPA (2000 mg/kg body weight) was orally administered to rats, which were monitored for 14 days. In the subacute toxicity study, rats were orally administered with EASPA daily for 28 days at doses of 1.75, 3.5, 7, and 14 mg/kg body weight. No rat in either the acute or subacute toxicity study exhibited mortality or clinical signs of toxicity. Further, these rats did not show any significant change in their mean body weight, food, and water intake, haematological and biochemical parameters as well as in the results of their histopathological examinations compared to those of control group rats. According to results of the acute toxicity, the LD50 of EASPA is estimated to be greater than 2000 mg/kg body weight. Considering the results of the subacute toxicity study, the oral administration of EASPA daily for 28 days was well tolerated up to the dose, 14 mg/kg by rats. These results will be useful in the development of a novel therapeutic agent from EASPA of the IC for the treatment of menorrhagia, which incapacitates a considerable proportion of women worldwide.


2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Panpan Zhen ◽  
Qian Zhao ◽  
Dandan Hou ◽  
Teng Liu ◽  
Dongqiao Jiang ◽  
...  

Hyperhomocysteinemia (HHcy) is a well-known independent risk factor for vascular diseases in the general population. This study was to explore the effect of genistein (GST), a natural bioactive compound derived from legumes, on HHcy-induced vascular endothelial impairment in ovariectomized ratsin vivo. Thirty-two adult female Wistar rats were assigned randomly into four groups (n=8): (a) Con: control; (b) Met: 2.5% methionine diet; (c) OVX + Met: ovariectomy + 2.5% methionine diet; (d) OVX + Met + GST: ovariectomy + 2.5% methionine diet + supplementation with genistein. After 12 wk of different treatment, the rats' blood, toracic aortas and liver samples were collected for analysis. Results showed that high-methionine diet induced both elevation of plasma Hcy and endothelial dysfunction, and ovariectomy deteriorated these injuries. Significant improvement of both functional and morphological changes of vascular endothelium was observed in OVX + Met + GST group; meanwhile the plasma Hcy levels decreased remarkably. There were significant elevations of plasma ET-1 and liver MDA levels in ovariectomized HHcy rats, and supplementation with genistein could attenuate these changes. These results implied that genistein could lower the elevated Hcy levels, and prevent the development of endothelial impairment in ovariectomized HHcy rats. This finding may shed a novel light on the anti-atherogenic activities of genistein in HHcy patients.


2000 ◽  
pp. 273-277 ◽  
Author(s):  
D Hofer ◽  
M Raices ◽  
K Schauenstein ◽  
S Porta ◽  
W Korsatko ◽  
...  

OBJECTIVE: The effects of the beta-3-receptor agonist CGP-12177 on thyroxine (T4) deiodination in sympathectomized (SX) interscapular brown adipose tissue (BAT) were assessed in 300 g body weight (BW) Wistar rats. DESIGN: Seven days after SX, groups of rats were implanted s.c. with pellets containing 5mg CGP-12177 or 5mg norepinephrine (NE) and were immediately placed at 4 degrees C for 24h. Other SX groups were injected with CGP-12177 or NE 1mg/kg BW i. p. and placed in the cold for 4h. The latter group was injected, in addition, with prazosin 0.4 mg/100g BW i.p. or propranolol 0.5mg/100g BW i.p. 15 min before and 2h after the administration of CGP-12177 or NE. METHODS: Two hours after the last injection of prazosin or propranolol, animals were killed and BAT was removed, homogenized and centrifuged at 500 g for 10 min at 4 degrees C. The infranatants were incubated during 60 min in the presence of dithiothreitol and 1 microCi [(125)I]T4. Aliquots were chromatographed on paper for the measurement of [(125)I]T4 and its deiodinated subproducts. RESULTS: CGP-12177 restored normal T4 deiodination in SX BAT from both groups, but NE was slightly more effective. Propranolol, although not prazosin, blocked the CGP-12177 effects. Contrariwise, the NE-induced rise in deiodination was blocked by prazosin and to a lesser extent by propranolol. CONCLUSIONS: The results indicate that CGP-12177 stimulated the in vivo activation of 5'-deiodinase type II activity predominantly via beta-3-receptor, without participation of alpha-1-receptors.


2014 ◽  
Vol 60 (4) ◽  
pp. 157-159
Author(s):  
Bianca Eugenia Ösz ◽  
C. E. Vari ◽  
Maria Dogaru

Abstract The prenatal exposure to selective serotonin reuptake inhibitors (SSRIs) is very controversial. There is no conclusive evidence for increased risk of malformations after SSRI use in pregnancy. The aim of the study was to determine how fluoxetine is affecting gestation and fetal development in rats. Twenty sexually mature female Wistar rats weighting between 250-260 g received 20 mg/kg body weight fluoxetine from the first day of gestation and during the entire gestation period.The drug was administered by oral route. Healthy, primipareus animals were selected along with 20 female Wistar rats, as control group. Mature males were caged with virgin females for an entire week. Rat’s behaviour during gestation, after birth and rats body weight was examined. The number of healthy pups was also noted. The females not giving birth after 21 days to any pup were anesthetized (halothane through gas scavenging apparatus untilled death) and the gravid uterus were dissected out and examined. Compared to the controlled group, in which weight gain was more significant, the animals from the experimental group had a slight increase in body weight. The weight gain normally induced by gestation, is less significant in fluoxetine treated rats due to the increase serotonin levels in the brain. The uteri examination of pregnant rats showed an increase in the number of dead and resorbed rat embryos. Preclinical studies suggest that the inclusion of fluoxetine in pregnancy category C is justified and the appropriateness of its administration in pregnancy is still an unresolved issue.


2020 ◽  
Vol 23 (2) ◽  
pp. 58
Author(s):  
Asri Sulfianti ◽  
Nur Hasanah ◽  
Agung Eru Wibowo ◽  
Kurnia Agustini ◽  
I Made Artika

Present investigation shows that the extract of C. aeruginosa attenuates DMBA-induced spleen carcinogenesis in Wistar rats. Three-week female Wistar rats were treated with three different C. aeruginosa extract doses (CA1: 40 mg/200 g body weight, BW; CA2: 80 mg/200 g BW; CA3: 160 mg/200 g BW) and were induced with DMBA after one-week administration of these doses. A commercial immunostimulant, and DMBA only were also given to each group as positive and negative control, respectively. The development of tumors was evaluated by investigating the incidence of tumor and tumor multiplicity during the experiment. Spleen mass index and histological parameters such as white pulp, centrum germinativum, and marginalis zone were also examined. Based on our study, the administration of C. aeruginosa extract during and after carcinogen induction gave several impacts on rat carcinogenesis. At the extract dose of 80 mg/200 g BW, tumor incidence of animals were least (P<0.05). However, all doses did not show any effect to the spleen mass index, though the highest dose (160 mg/200 g BW) was found to cause changes in white pulp and marginalis zone boards. This trend indicates that it takes higher dose to cause an immune response effect reaching the organs.


2022 ◽  
Vol 66 (9-10) ◽  
pp. 17-23
Author(s):  
V. V. Kudelkina ◽  
A. S. Khalansky ◽  
A. I. Alekseeva ◽  
P. L. Gorelikov ◽  
A. M. Kosyreva

The search for effective approaches to the treatment of patients with glioblastoma is one of the difficult tasks of neurooncology; standard methods of therapy show limited results. Combined therapy, which includes different antitumor mechanisms, can increase its effectiveness. The combination of PLGA nanoform of doxorubicin (Dox-PLGA), antitumor cytokine — interferon alfa (IFN-α), and nitrogen oxide (NO) donor nitroglycerin (NG) was investigated in this work both in vitro (rat C6 glioma) and in vivo (rat 101.8 glioblastoma). MTT assay in the C6 cell line showed great cytotoxicity and antiproliferative effect of the combination of IFN-α with Dox-PLGA and NG. The lowest tumour cell survival was observed when using a high dose of IFN-α (10 ng/ml) in mono-mode. In the in vivo experiment, 32 female Wistar rats with 101.8 glioblastoma received therapy in the following modes: Dox-PLGA + NG; Dox-PLGA + IFN-α; Dox- PLGA + IFN-α + NG. There was a significant increase in median survival and life expectancy (ILE) in all groups receiving therapy compared to the group that did not undergo treatment. The longest median lifespan (27 days), survival up to 100 days (1 animal), ILE (131%) were observed in animals that received the combination Dox-PLGA + IFN-α+ NG, compared to the group without treatment, in which the median lifespan was 15 days. Thus, the therapy of experimental glioblastoma both in vivo and in vitro with the combination of Dox-PLGA + IFN-α + NG has the most pronounced therapeutic and antitumor effect, which must be taken into account when developing new more effective methods of treating human glioblastomas.


1999 ◽  
Vol 22 (3) ◽  
pp. 415-417 ◽  
Author(s):  
Lusânia M. Greggi Antunes ◽  
Joana D.C. Darin ◽  
Maria de Lourdes P. Bianchi

The ability of vitamin C (VC) to protect against the clastogenic action of the chemotherapeutic agent cisplatin (DDP, cis-diamminedichloroplatinun II) in rat bone marrow cells was evaluated. DDP was administered to Wistar rats either alone or after treatment with VC. The rats were treated with VC (50, 100 or 200 mg/kg body weight) by gavage 10 min before the administration of DDP (5 mg/kg body weight, ip) and then sacrificed 24 h after treatment. VC significantly reduced (by about 70%) the clastogenicity of DDP in rat bone marrow cells. The antioxidant action of VC presumably modulates the clastogenic action of DDP.


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