Acylated Ghrelin Protects the Hearts of Rats from Doxorubicin-Induced Fas/FasL Apoptosis by Stimulating SERCA2a Mediated by Activation of PKA and Akt

This study investigated if the cardioprotective effect of acylated ghrelin (AG) against doxorubicin (DOX)-induced cardiac toxicity in rats involves inhibition of Fas/FasL-mediated cell death. It also investigated if such an effect is mediated by restoring Ca⁺² homeostasis from the aspect of stimulation of SERCA2a receptors. Adult male Wistar rats were divided into 4 groups (20 rats/each) as control, control + AG, DOX, and DOX + AG. AG was co-administered to all rats consecutively for 35 days. In addition, isolated cardiomyocytes were cultured and treated with AG in the presence or absence of DOX with or without pre-incubation with [D-Lys3]-GHRP-6 (a AG receptor antagonist), VIII (]an Akt inhibitor), or KT-5720 (a PKA inhibitor). AG increased LVSP, dp/dt_max, and dp/dt_min in both control and DOX-treated animals and improved cardiac ultrastructural changes in DOX-treated rats. It also inhibited ROS in control rats and lowered LVEDP, intracellular levels of ROS and Ca²⁺, and activity of calcineurin in LVs of DOX-treated rats. Concomitantly, it inhibited LV NFAT-4 nuclear translocation and downregulated their protein levels of Fas and FasL. Mechanistically, in control or DOX-treated hearts or cells, AG upregulated the levels of SERCA2a and increased the activities of PKA and Akt, leading to increase phosphorylation of phospholamban at Ser¹⁶ and Thr¹⁷. All these effects were abolished by D-Lys3-GHRP-6, VIII, or KT-5720 and were independent of food intake or GH/IGF-1. In conclusion, AG cardioprotection against DOX involves inhibition of extrinsic cell death and restoring normal Ca⁺² homeostasis.

Suppression of glomerular damage and apoptosis and biomarkers of acute kidney injury induced by acetaminophen toxicity using a combination of resveratrol and quercetin

Acute renal failure induced by a toxic dose of acetaminophen (also known as paracetamol, or APAP) is common in both humans and experimental animal models. Glomerular ultrastructural alterations induced by APAP overdose associated with the suppression of biomarkers of kidney injury have not been investigated before. Also, we investigated whether the combined polyphenolic antioxidants and anti-inflammatory compounds, resveratrol (RES) and quercetin (QUR) can protect against APAP-induced nephrotoxicity. Rats either received a single dose of APAP (2 g/kg) before being sacrificed after 24 hours or were pretreated for 7 days with combined doses of RES (30 mg/kg) and QUR (50 mg/kg) before being given a single dose of APAP and then sacrificed 24 hours post APAP ingestion. APAP significantly (p < 0.05) increased blood levels of urea, creatinine, malondialdehyde (MDA), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α), which were effectively reduced by RES + QUR. In addition, APAP overdose induced the tissue expression of the apoptotic biomarker, p53, and caused profound kidney damage as demonstrated by substantial alterations to the glomerular basement membrane, podocytes, endothelial cells, widening of Bowman's space, and vacuolation of the cells lining the parietal layer, which were substantially protected by RES + QUR. Furthermore, a significant (p < 0.0001) positive correlation was observed between either glomerular basement membrane or podocyte foot processes and these parameters, urea, creatinine, MDA, and TNF-α. Thus, we conclude that APAP induces alterations to the glomerulus ultrastructure, which is protected by resveratrol plus quercetin, which also reduces blood levels of urea and creatinine, and biomarkers of oxidative stress and inflammation.

Metformin suppresses aortic ultrastrucural damage and hypertension induced by diabetes: a potential role of advanced glycation end products

Cardiovascular disease secondary to diabetes represents a significant challenge to the health community. The advanced glycation end products (AGEs) play an important role in diabetes-mediated vascular injury. We tested whether metformin can suppress aortic AGEs production and protect against aortic injuries (aortopathy) and hypertension in streptozotocin-induced type 2 diabetes mellitus (T2DM) animal model. T2DM was induced in rats two weeks after being fed on a high carbohydrate and fat diet (HCFD), and continued on a HCFD until being sacrificed at week 12 (model group). The protective group was put on metformin two weeks before diabetic induction and continued on metformin and HCFD until the end of the experiment, at week 12. Using electron microscopy examinations, we observed in the model group substantial damage to the ultrastructure of aortic endothelial and vascular smooth muscle layers as demonstrated by markedly distorted vacuolated endothelial and vascular smooth muscle cells with pyknotic nuclei detached from the underlying basement membrane, which were protected by metformin. Also, metformin significantly (p < .05) decreased both systolic and diastolic blood pressure, aortic levels of AGEs, and blood levels of oxidative stress and inflammatory biomarkers. We conclude that metformin protects against T2DM-induced aortopathy and hypertension, possibly via the inhibition of AGEs, inflammation, and oxidative stress.

Melatonin Improves Memory Deficits in Rats with Cerebral Hypoperfusion, Possibly, Through Decreasing the Expression of Small-Conductance Ca2+-Activated K+ Channels

This study investigated the expression pattern, regulation of expression, and the role of hippocampal small-conductance Ca²⁺-activated K⁺ (SK) channels in memory deficits after cerebral hypoperfusion (CHP) with or without melatonin treatment, in rats. Adults male Wistar rats (n = 20/group) were divided into (1) a sham (2) a sham + melatonin (3) a two-vessel occlusion (2-VO) model, and (4) a 2-VO + melatonin. Melatonin was administered (i.p.) to all rats at a daily dose of 10 mg kg^-1 for 7 days starting at the time of 2-VO-induction. In contrast to 2-VO rats, melatonin increased the latency of the passive avoidance learning test and decreased time to find the hidden platform in Water Morris Test in all tested rats. In addition, it concomitantly downregulated SK1, SK2, and SK3 channels, downregulated mRNA levels of TNFα and IL-1β, enhanced BDNF levels and activity of PKA levels, and restored the levels of cholinergic markers in the hippocampi of the treated-rats. Mechanistically, melatonin significantly prevented CHP-induced activation of ERK1/2, JNK, and P38 MAPK at least by inhibiting ROS generation and enhancing the total antioxidant potential. In cultured hypoxic hippocampal neurons, individual blockage of MAPK signaling by the MEK1/2 inhibitor (U0126), but not by the P38 inhibitor (SB203580) or JNK inhibitor (SP600125), completely prevented the upregulation of all three kinds of SK channels. These data clearly confirm that upregulation of SK channels plays a role in CHP-induced memory loss and indicate that melatonin reverses memory deficits after CHP in rats, at least by, downregulation of SK1, SK2, and SK3 channels in their hippocampi.

Vitamin E ameliorates alterations to the articular cartilage of knee joints induced by monoiodoacetate and diabetes mellitus in rats

We recently reported an animal model of osteoarthritis (OA) induced by a combination of the chondrocyte glycolysis inhibitor, monoiodoacetate (MIA) and the agent that induces diabetes mellitus, streptozotocin (STZ). Here we investigated the potential protective effect of the antioxidant and anti-inflammatory agent, vitamin E against MIA+STZ-induced OA. Therefore, rats were either injected once with MIA (2 mg/50 μL) + 65 mg/kg STZ before being sacrificed after 8 weeks (model group) or were treated immediately after MIA+STZ injections with vitamin E (600 mg/kg; thrice a week) before being sacrificed after 8 weeks (treatment group). Using scanning and transmission electron microscopy examinations, we observed in the model group a substantial damage to the articular cartilage of the knee joint as demonstrated by the destruction of the chondrocytes, territorial matrix, disrupted lacunae, collagen fibers, and profound chondrocyte ultrastructural alterations such as degenerated chondrocyte, irregular cytoplasmic membrane, damaged mitochondria and rough endoplasmic reticulum, vacuolated cytoplasm, presence of lipid droplets and different sizes of lysosomes, which were substantially but not completely protected by vitamin E. H&E stained sections of knee joint articular cartilage showed that MIA+STZ induced damage to the chondrocyte and territorial matrix. Vitamin E also significantly (p < .05) inhibited MIA+STZ-induced blood levels of the inflammatory biomarkers, tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) that are known to be modulated in OA and diabetes. We conclude that vitamin E protects against MIA+STZ-induced knee joints injuries in rats, which is associated with the inhibition of biomarkers of inflammation.

Insulin Suppresses Type 1 Diabetes Mellitus-Induced Ventricular Cardiomyocyte Damage Associated with the Inhibition of Biomarkers of Inflammation and Oxidative Stress in Rats

Aims: We sought to determine whether insulin can protect against type 1 diabetes mellitus (T1DM)-induced cardiac ultrastructural alterations in an animal model of the disease. This has not been investigated before. Methods: Rats were either injected once with 65 mg/kg streptozotocin (STZ) before being sacrificed after 8 weeks or were treated with a daily injection of insulin 2 days by STZ and continued until being sacrificed. Results: Harvested tissues obtained from left ventricles in the untreated T1DM rats showed substantial damage to the cardiomyocyte ultrastructure as demonstrated by disintegrated myofibrils and their sarcomeres, damaged mitochondria and lipid droplets, which was substantially protected by insulin. Insulin also significantly inhibited T1DM-induced hyperglycemia (p < 0.001), dyslipidemia (p < 0.0001), malondialdehyde (MDA; p < 0.0001), tumor necrosis factor-alpha (TNF-α; p < 0.001) and interleukin-6 (p < 0.001). We further demonstrated a significant (p ≤ 0.001) correlation between either sarcomere or mitochondrial injury scoring and the serum levels of glucose, dyslipidemia, and biomarkers of oxidative stress (OxS) and inflammation. Conclusions: These results indicate that insulin effectively suppresses left ventricular cardiomyocyte ultrastructural damage, which substantially slows down the progression of diabetic cardiomyopathy for 8 weeks in a rat model of T1DM, possibly due to the glycemic control and inhibition of dyslipidemia, OxS and inflammation.

Swim exercise inhibits hemostatic abnormalities in a rat model of obesity and insulin resistance

BACKGROUND

We sought to determine whether swim exercise can inhibit high carbohydrate and fat diet (HCFD)-induced biomarkers of coagulation and thrombosis.

MATERIAL AND METHODS

Rats were either fed with HCFD (model group) or a standard laboratory chow (control group) for 15 weeks. Swim exercise-'treated' rats started swim exercise training from the 11^th week until being sacrificed, on Week 15.

RESULTS

HCFD caused a significant increase in blood glucose, insulin resistance (HOMA-IR), lipidemia, and inflammatory biomarkers. In addition, HCFD significantly modulated coagulation and thrombosis biomarkers; fibrinogen, plasminogen activator inhibitor-1, von Willebrand factor, prothrombin time, activated partial thromboplastin time, blood clotting and bleeding time, and ADP-induced platelet aggregation that was effectively inhibited by swimming exercises.

CONCLUSIONS

We demonstrate that in an animal model of obesity and insulin resistance, there is a significant change in hemostasis, which is ameliorated by swim exercise.

Crataegus aronia enhances sperm parameters and preserves testicular architecture in both control and non-alcoholic fatty liver disease-induced rats

CONTEXT

Crataegus aronia (syn. Azarolus L.) (Rosaceae) is used in traditional medicine due to its hypolipidaemic and antioxidant properties.

OBJECTIVES

This study investigates the effect of C. aronia whole plant aqueous extract on sperm parameter and testicular structure in control and non-alcoholic fatty liver disease (NAFLD)-induced rats.

MATERIALS AND METHODS

Male rats were divided into six groups (10 rats each) as control fed a standard diet (STD) (10% kcal), STD + C. aronia (200 mg/kg), high-fat diet (HFD) (45% kcal), HFD + C. aronia, HFD followed by C. aronia, and C. aronia followed by HFD. Rats were treated with C. aronia (once/day, orally) for four weeks.

RESULTS

Compared with STD rats, STD rats co-treated with C. aronia had lower hepatic triglycerides (0.58 vs. 0.42 mg/g) and cholesterol (5.4 vs. 3.27 mg/g) contents, higher levels of testosterone (8.43 vs. 10.9 ng/mL), luteinizing hormone (6.05 vs. 8.1 mIU/mL) and follicle-stimulating hormone (5.8 vs. 8.0 mIU/mL) and increased epididymis weight (1.28 vs. 1.5g) and sperm count (133.2 vs. 148.3 million/0.1 mg) and motility (66.8%vs. 77.6%). They showed increased testicular levels of glutathione (6.3 vs. 7.75 µM/L) and higher protein levels of Nrf2 (0.37 vs. 0.79), γ-glutamylcysteine synthetase (0.27 vs. 0.5) and superoxide dismutase (0.92 vs. 2.1). Concomitant or post-treatment of C. aronia to NAFLD rats prevented the declines in sperm parameters and damage in the testis by similar effects like those found in the STD rats.

DISCUSSION AND CONCLUSIONS

This study encourages the use of C. aronia in further future clinical studies.

Insulin protects against hepatocyte ultrastructural damage induced by type 1 diabetes mellitus in rats

Diabetic complications that affect vital organs such as the heart and liver represent a major public health concern. The potential protective effects of the hormone insulin against hepatocyte ultrastructural alterations induced secondary to type 1 diabetes mellitus (T1DM) in a rat model of the disease have not been investigated before. Therefore, rats were injected once with 65 mg/kg streptozotocin (T1DM group) and the protection group (T1DM+Ins) received a daily injection of insulin 48 h post diabetic induction by streptozotocin and continued until being sacrificed at week 8. The harvested liver tissues were examined using transmission electron microscopy (TEM) and blood samples were assayed for biomarkers of liver injury enzyme, glycemia, lipidemia, inflammation, and oxidative stress. TEM images showed that T1DM induced profound hepatocyte ultrastructural alterations as demonstrated by pyknotic nucleus, condensation of chromatin, irregular nuclear membrane, swollen mitochondria, dilated rough endoplasmic reticulum, damaged intercellular space, and accumulation of few lipid droplets inside the hepatocyte cytoplasm, which were substantially protected with insulin. In addition, the blood chemistry profile complements the TEM data as demonstrated by an increase in serum levels of alanine aminotransferase (ALT), dyslipidemia, C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and malondialdehyde (MDA) by T1DM that were significantly (p < 0.05) reduced with insulin injections. Thus, we conclude that insulin effectively protects against T1DM-induced liver injury in rats for a period of 8 weeks, possibly due to the inhibition of inflammation, oxidative stress, and dyslipidemia.

A synergistic protective effect of selenium and taurine against experimentally induced myocardial infarction in rats

This study investigated the protective effect of subacute pre-adminsitration of either selenium (Se), taurine (Tau), or both drugs in combination against experimentally induced myocardial infarction (MI) in rats and illustrates the possible mechanisms of action. While solely pre-administration of Se or Tau resulted in partial amelioration in all of the measured parameters in MI rats, concomitant administration of both drugs to MI rats significantly restored contractility function by increasing LVSP and decreasing LVEDP and significantly normalized serum levels of LDH, CK-MB and BNP and restored normal cardiac architecture. This concomitant treatment acted by increasing the activity of major antioxidant enzymes (SOD and GPx), decreasing the levels of inflammatory markers including TNF-α, IL-6 as well as levels of Bcl-2 and caspase-3 and downregulating mRNA levels of Bax and P53, markers of apoptosis. In conclusion, a combination of Se and Tau provides a new strategy to alleviate MI-induced cardiac dysfunction.

Exercise protects against insulin-dependent diabetes-induced osteoarthritis in rats: A scanning electron microscopy study

We tested the hypothesis that swim exercise can protect the articular cartilage from damages induced secondary to insulin-dependent diabetes mellitus in rats using the scanning electron microscopy and to monitor the blood levels of oxidative and antioxidative stress biomarkers that are known to be modulated in osteoarthritis (OA). A profound damage to the cartilage was observed in the diabetic rats. Our findings also show that swim exercise protects the knee joints from damage induced by diabetes as well as significantly inhibiting OA-induced upregulation of thiobarbituric acid reactive substances (TBARS) and tumor necrosis factor alpha (TNF-α) and augmented superoxide dismutase (SOD) inhibition by OA. Thus, we demonstrated an effective protection by swim exercise against diabetes-induced OA in a rat model of the disease.

Insulin and vanadium protect against osteoarthritis development secondary to diabetes mellitus in rats

OBJECTIVE

Diabetic complications such as cardiovascular disease and osteoarthritis (OA) are among the common public health problems. The effect of insulin on OA secondary to diabetes has not been investigated before in animal models. Therefore, we sought to determine whether insulin and the insulin-mimicking agent, vanadium can protect from developing OA in diabetic rats.

METHODS

Type 1 diabetes mellitus (T1DM) was induced in Sprague-Dawley rats and treated with insulin and/or vanadium. Tissues harvested from the articular cartilage of the knee joint were examined by scanning electron microscopy, and blood samples were assayed for oxidative stress and inflammatory biomarkers.

RESULTS

Eight weeks following the induction of diabetes, a profound damage to the knee joint compared to the control non-diabetic group was observed. Treatment of diabetic rats with insulin and/or vanadium differentially protected from diabetes-induced cartilage damage and deteriorated fibrils of collagen fibers. The relative biological potencies were insulin + vanadium >> insulin > vanadium. Furthermore, there was about 2- to 5-fold increase in TNF-α (from 31.02 ± 1.92 to 60.5 ± 1.18 pg/ml, p < 0.0001) and IL-6 (from 64.67 ± 8.16 to 338.0 ± 38.9 pg/ml, p < 0.0001) cytokines and free radicals measured as TBARS (from 3.21 ± 0.37 to 11.48 ± 1.5 µM, p < 0.0001) in the diabetic group, which was significantly reduced with insulin and or vanadium. Meanwhile, SOD decreased (from 17.79 ± 8.9 to 8.250.29, p < 0.0001) and was increased with insulin and vanadium. The relative potencies of the treating agents on inflammatory and oxidative stress biomarkers were insulin + vanadium >> insulin > vanadium.

CONCLUSION

The present study demonstrates that co-administration of insulin and vanadium to T1DM rats protect against diabetes-induced OA possibly by lowering biomarkers of inflammation and oxidative stress.

Sevoflurane has less effect than halothane on pulmonary afferent activity in the rabbit

We have compared the effects of sevoflurane and halothane on the discharge frequencies of 19 slowly adapting and four rapidly adapting lung receptors in the rabbit by recording from single vagal fibres. Both agents reduced the discharge frequency of slowly adapting receptors during expiration (P < 0.0005), halothane having a greater effect than sevoflurane (P < 0.0005). Neither agent had any effect on discharge frequency at the end of inspiration when discharge frequency is at a maximum. Neither agent affected the discharge frequency of rapidly adapting receptors.

Oral endotracheal intubation of rabbits (Oryctolagus cuniiculus)

Endotracheal intubation of rabbits is reported, both personally and in the literature, to be so difficult that special equipment has been constructed by other workers to facilitate the procedure. We report that the positioning of the operator, behind the animal, viewing from the dorsal surface of the head, facilitates this procedure enormously.