Aged Male Sprague-Dawley Rats Research Articles

Protective effects of electroacupuncture on senile osteoporosis in rats.

The objectives were to explore the protective effects of electroacupuncture (EA) on senile osteoporosis in aged rats and investigate the underlying mechanisms. This study included aged (24-month-old; n = 16) and young (3-month-old; n = 8) male Sprague-Dawley rats. Aged rats were further randomized 1:1 to an aged control group (Aged; n = 8) and an EA treatment group (EA; n = 8). The 3-month-old rats served as young controls (Young). EA rats received EA at ST36, SP6, GB34 and SP10 bilaterally for 30 min a day, 5 days a week, for 8 weeks. EA significantly increased serum markers of bone formation in Aged rats. There were no significant differences in serum markers of bone resorption between EA and Aged rats. Deterioration of bone mineral density (BMD) and trabecular bone architecture was observed in the Aged group, while EA significantly increased BMD of the left femur and L5 vertebral body in aged rats. Aging-induced deterioration of trabecular bone architecture was partially reversed in EA rats. Runx2 and Osterix mRNA and protein levels were significantly increased and peroxisome proliferator-activated receptor (PPAR)γ was significantly decreased in bone marrow cells in EA compared with Aged groups. The mRNA and protein levels of core constituents of the Wnt/β-catenin signaling pathway (Wnt3a, low-density lipoprotein receptor-related protein (LRP)5 and β-catenin) were significantly increased and Dickkopf 1 was significantly decreased in bone marrow cells in EA compared with Aged groups. EA may prevent bone loss and deterioration in aged rats by promoting osteogenesis via a mechanism that may involve activation of the Wnt/β-catenin signaling pathway. EA may represent a therapeutic option for senile osteoporosis.

Abstract P378: Impaired Diurnal Control of Blood Pressure and Sodium Excretion in Aged Hypertensive Male Sprague Dawley Rats

Hypothesis: The diurnal rhythmicity of blood pressure (BP) and sodium excretion is important to blood pressure regulation and is strongly influenced by the circadian clock genes. We hypothesized that the diurnal control of BP and natriuresis is impaired in aged male Sprague Dawley (SD) rats and may be associated with altered kidney expression of circadian clock gene proteins. Methods: Radiotelemetry (to record mean arterial BP (MAP)) and metabolic balance (to assess sodium excretion) was conducted in 3-month-old (3M) and 16-month-old (16M) male SD rats. On a separate day, 3M and 16M rats received an acute 900 μEq NaCl load by oral gavage at ZT0 and sodium excretion was assessed. Total renal cortex expression of Per1 and Bmal1 was assessed by immunoblotting (N=4-6/group ± SD). Results: 16M rats exhibit significantly increased MAP and 24-h sodium retention vs. 3M rats [MAP (mmHg) 3M 102±4 vs. 16M 127±5, P<0.05; 24h Na retention (mEq/24h) 3M 0.3±0.1 vs. 16M 0.8±0.2, P<0.05). 16M rats exhibit an attenuation of the circadian MAP pattern compared to 3M rats. Aged rats have a significant decrease in the blood pressure rise during the dark (active) vs. 3M rats (Dark phase increase in MAP (mmHg) 3M +13.6±2.1 vs. 16M +4.8±1.9, P<0.05). 3M rats exhibit a classical diurnal pattern of 24-h sodium excretion with increased natriuresis during the dark (active) phase – a response that is attenuated in 16M rats that exhibit a significant reduction in the increase in natriuresis in the dark phase (Light phase UNaV (μEq/12h) 3M 380±48 vs. 16M 410±36, Dark phase natriuresis 3M 620±31 vs 16M 502±27, P<0.05). 16M rats had an impaired natriuretic response to an acute oral NaCl load in the first 12h post-gavage (UNaV 12h (μEq/12h) 3M 681±42 vs. 16M 243±39, P<0.05). In 16M old rats there was no change in renal Per1 and decreased renal Bmal1 protein (Bmal1 fold change 16M vs. 3M, 0.65±0.7, P<0.05). Conclusions: We observed impaired circadian control of blood pressure and renal sodium excretion in aged male SD rats. These changes in renal sodium handling may reflect endogenous decreases in renal Bmal1 levels with age and contribute to the observed hypertensive phenotype in aged rats.

Sex Differences in Blood Pressure Response to Dietary Salt in Aged Rats

Background: The impact of dietary salt intake on blood pressure (BP) and its variability is critical for understanding cardiovascular risks, yet there is a scarcity of data exploring these effects across different sexes, particularly in the context of aging. Methods: This study examined the effects of varying salt diets on BP among aged female and male Sprague-Dawley rats (22-24 months). Subjects were administered either a control (0.4% NaCl), low (0.1% NaCl), or moderate-high (1% NaCl) salt diet for 12 weeks. BP levels and variability were measured at baseline, 2, 4, 8, and 12 weeks after dietary onset. Results: Preliminary findings revealed that, from the eighth week following dietary initiation, aged male rats exhibited a pronounced elevation in systolic BP when exposed to all types of diets, in contrast to aged female rats consuming low-salt diets. Additionally, aged male rats presented with a marked rise in diastolic BP upon consumption of both control and high-salt diets relative to female rats across all diets from the eighth week onward. Although systolic BP variability did not differ significantly between sexes, there were marked sex-specific differences in diastolic BP variability. Conclusions: The study identified sex-specific responses in BP and its variability to dietary salt intake in aged rats, with male rats showing heightened sensitivity. These findings underscore the importance of considering sex as a biological variable in dietary and cardiovascular health research. This research was funded by the START-UP FUNDING OF HANGZHOU NORMAL UNIVERSITY, grant number 4255C50221204123 (Dr. Fen Sun). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Sprague-Dawley rats differ in responses to medial perforant path paired pulse and tetanic activation as a function of sex and age.

Network plasticity in the medial perforant path (MPP) of adult (5-9 mo) and aged (18-20 mo) urethane-anesthetized male and female Sprague-Dawley rats was characterized. Paired pulses probed recurrent networks before and after a moderate tetanic protocol. Adult females exhibited greater EPSP-spike coupling suggesting greater intrinsic excitability than adult males. Aged rats did not differ in EPSP-spike coupling but aged females had larger spikes at high currents than males. Paired pulses suggested lower GABA-B inhibition in females. Absolute population spike measures were larger post-tetani in female rats than male rats. Relative population spike increases were greatest in adult males relative to females and to aged males. EPSP slope potentiation was detected with normalization in some post-tetanic intervals for all groups except aged males. Tetani shortened spike latency across groups. Tetani-associated NMDA-mediated burst depolarizations were larger for the first two trains in each tetanus in adult males than other groups. EPSP slopes over 30 min post-tetani predicted spike size in female rats, but not in males. Replicating newer evidence MPP plasticity in adult males was mediated by increased intrinsic excitability. Female MPP plasticity was related to synaptic drive increases, not excitability increases. Aged male rats were deficient in MPP plasticity.SIGNIFICANCE STATEMENTThe medial perforant path (MPP)-dentate gyrus (DG) granule cell synapse was the site of discovery of long-term potentiation in the mammalian nervous system but considering the current interest in sex and aging, surprisingly few studies have directly examined these variables in relation to tetanus-induced long-term and short-term (paired pulse) plasticity. Using an interleaved current-paired pulse interval protocol and moderate tetanic protocol young (5-9mo) and old (18-20mo) male and female urethane anesthetized rats were found to differ in levels of granule cell intrinsic excitability, E-S coupling, GABA-B inhibition, and tetanic NMDA current contributions to post-tetanic population spike potentiation. This study provides a platform or future examination of sex- and age-related changes in MPP-DG function.

The Mechanism of miR-21-5p/TSP-1-Mediating Exercise on the Function of Endothelial Progenitor Cells in Aged Rats.

(1) Background: The declined function of peripheral circulating endothelial progenitor cells (EPCs) in aging individuals resulted in decreased endothelial cell regeneration and vascular endothelial function. Improving EPCs function in aging individuals plays an important role in preventing cardiovascular diseases. (2) Methods: Thirty aged (18-month-old) male Sprague-Dawley rats were randomly divided into control and exercise groups. An aerobic exercise intervention was performed 5 days/week for 8 weeks. EPCs functions, miR-21-5p, and TSP-1 expressions were detected after the intervention. The senescence rate, proliferation, and migration of EPCs were examined after overexpression of miR-21-5p and inhibition of TSP-1 expression. (3) Results: The senescence rate, proliferation, and migration of EPCs in exercise groups were significantly improved after exercise intervention. The miR-21-5p expression was increased and the TSP-1 mRNA expression was decreased in the EPCs after the intervention. miR-21-5p overexpression can improve EPCs function and inhibit TSP-1 expression but has no effect on senescence rate. Inhibition of TSP-1 expression could improve the function and reduce the senescence rate. (4) Conclusions: Our results indicate that long-term aerobic exercise can improve the functions of EPCs in aging individuals by downregulating TSP-1 expression via miR-21-5p, which reveals the mechanism of exercise in improving cardiovascular function.

Treadmill training mitigates bone deterioration via inhibiting NLRP3/Caspase1/IL-1β signaling in aged rats

IntroductionAlthough aerobic physical exercise may improve osteoporosis during ageing, the underlying mechanism of the favorable effects remains unclear. The aim of this study was to examine the localized and generalized proinflammatory indicators and the adaptive skeletal responses to treadmill training in aged rats to explore the potential mechanisms by which treadmill training impacts bone deterioration in a natural aged rat model.Materials and methodsA total of 24 Sprague Dawley (SD) rats were included in this study. Sixteen of all these animals were twenty-four months natural aged male SD rats, which were distributed into two groups (n = 8/group): AC group with sham treadmill training, and AT group with 8 weeks treadmill training. The remaining 8 were six months male SD rats matched subline and supplier, which were used as the adult control group with sham treadmill training (YC group, n = 8). The serum, bone marrow, fresh femur, tibia, and lumbar spine were harvested for molecular biological analysis, bone mineral density (BMD) testing, and micro-CT analysis after 8 weeks of treadmill training.ResultsAfter 8 weeks of intervention, the results showed that treadmill training increased BMD and inhibited deterioration of bone microarchitecture of hind limb bones. Further analysis showed that treadmill training increased serum P1CP concentration and decreased serum CTX-1level. Interestingly, treadmill training down-regulated the protein expressions of proinflammatory indicators, including NLRP3, proCaspase1, cleaved Caspase1, IL-1β, and GSDMD-N, and the mRNA levels of NLRP3, Caspase1, and IL-1β of the bone marrow. In addition, treadmill training also inhibited serum TNF-α and IL-1β concentration. However, 8 weeks of treadmill training did not increase BMD and bone microarchitecture in the lumbar spine.ConclusionTreadmill training mitigates the ageing-induced bone loss and reverses the deterioration of bone microarchitecture in hind limbs probably through inhibiting NLRP3/Caspase1/IL-1β signaling to attenuate low-grade inflammation and improve the inflammatory bone microenvironment.

Aging Impairs Phrenic Long‐Term Facilitation in Rats by an Adenosine‐Dependent Mechanism

Phrenic long‐term facilitation (pLTF) is a form of respiratory plasticity elicited by acute intermittent hypoxia (AIH). AIH activates competing intracellular signaling cascades, initiated by phrenic motor neuron serotonin 2 and adenosine 2A (A2A) receptors, respectively. With moderate AIH (mAIH), the serotonin‐dependent Q pathway to phrenic motor facilitation dominates, with an adenosine constraint. Consequently, spinal A2Areceptor inhibition enhances mAIH‐induced pLTF. In middle‐aged male, and geriatric acyclic female rats, pLTF is attenuated through unknown mechanisms. We hypothesize that basal spinal adenosine levels are elevated in aged rats, thereby undermining mAIH‐induced pLTF. Thus, we predict that spinal A2A receptor inhibition in aged male rats will restore pLTF to levels equal to young male rats with A2A receptor inhibition. A selective A2A receptor antagonist (MSX‐3; 10 uM, 12 uL) or vehicle (0.9% sterile saline) were delivered intrathecally (C4) in anesthetized, vagotomized, paralyzed and ventilated young (3‐6 months) and aged (20‐22 months) male Sprague‐Dawley rats prior to mAIH (3, 5 min hypoxic episodes; arterial Po2= 45‐55 mmHg). In young males, mAIH elicits ~ 60% pLTF at 60 min post‐AIH. Spinal A2A receptor inhibition significantly enhanced mAIH‐induced pLTF in young males (119 + 5%; n = 6) vs vehicle controls (55 + 9%; n = 6; p < 0.001) and time controls (12 + 4%; n = 6; p < 0.001). In aged males, A2A receptor inhibition enhanced mAIH‐induced pLTF to a greater extent (186 + 19%; n = 7) vs vehicle controls (25 + 11%; n = 7; p < 0.001) and time controls (3 + 5%; n = 4; p < 0.001). Measured basal adenosine levels in ventral C3‐C5 homogenates were significantly elevated in aged vs young males (p = 0.008). Preliminary data suggest aged female rats (16‐18 months) also have enhanced mAIH‐induced pLTF with A2A receptor inhibition (173+ 24%; n = 3) vs vehicle controls (53 + 7%; n = 3) and time controls (5 + 17%; n = 2) in persistent estrus. These findings advance our understanding of mechanisms whereby age undermines mAIH‐induced phrenic motor plasticity. Understanding age and sex effects on AIH‐induced respiratory motor plasticity is crucial as we harness therapeutic AIH to treat severe neuromuscular disorders that compromise breathing.

Spirulina extract improves age-induced vascular dysfunction

Context Vascular dysfunction is considered a hallmark of ageing that has been associated with altered vasomotor responses, in which nitric oxide (NO) and reactive oxygen species participate. The consumption of Spirulina extracts, with antioxidant properties, increased recently. Objective This study investigates the effect of Spirulina aqueous extract (SAE) on the vascular function of the aorta from aged rats. Materials and methods Aortic segments from aged male Sprague-Dawley rats (20–22 months old) were exposed to SAE (0.1% w/v, for 3 h) to analyse: (i) the vasodilator response induced by acetylcholine (ACh), by the NO donor sodium nitroprusside (SNP), by the carbon monoxide releasing molecule (CORM) and by the KATP channel opener, cromakalim (CK); (ii) the vasoconstrictor response induced by KCl and noradrenaline (NA); (iii) the production of NO and superoxide anion, and (iv) the expression of the p-eNOS and HO-1 proteins. Results Incubation with SAE increased the expression of p-eNOS (1.6-fold) and HO-1 (2.0-fold), enhanced NO release (1.4-fold in basal and 1.9-fold in ACh-stimulated conditions) while decreased the production of superoxide (0.7-fold). SAE also increased the sensitivity (measured as pEC50) to ACh (control: −7.06 ± 0.11; SAE: −8.16 ± 0.21), SNP (control: −7.96 ± 0.16; SAE: −9.11 ± 0.14) and CK (control: −7.05 ± 0.39; SAE: −8.29 ± 0.53), and potentiated the response to KCl (1.3-fold) and to NA (1.7-fold). Conclusion The antioxidant properties of SAE improved the vasomotor responses of aorta from aged rats. These results may support the use of Spirulina as a protection against vascular dysfunction.

Abstract 6970: Extracellular Vesicles Prevent Post-Operative Atrial Fibrillation

Half of patients recovering from cardiac surgery experience a malignant form of atrial fibrillation that results from inflammation in the pericardial space surrounding the heart. Given that post-operative atrial fibrillation (POAF) increases mortality, effective measures to prevent or treat POAF are highly desirable. In this study, we built on previous work to see if extracellular vesicles (EVs) isolated from human atrial explant-derived cell conditioned media can prevent POAF. Hypothesis: Human EVs will reduce AF inducibility in a rat model of sterile pericarditis by reducing inflammation and the malignant pro-fibrillatory transformation of atrial fibroblasts. Methods and Results: Middle aged female and male Sprague-Dawley rats (6 months old) were randomized to sham operation (n=24; 12 females, 12 males) or induction of sterile pericarditis followed by intra-atrial injection of 10 8 human EVs (n=34; 17 females, 17 males) or vehicle (n=34; 17 females, 17 males). Three days later, all rats underwent invasive electrophysiological testing prior to sacrifice. As expected, pericarditis increased the probability of inducing AF (Figure Panel A). EV treatment reduced the probability of AF. Recipient sex did not alter this effect. Analysis of atrial tissue histology (H&E staining) and lysate (Luminex assays for IL-2, Il-18, MCP-1 and PDGF-AB) revealed that EV treatment abrogated the pro-inflammatory effects of pericarditis. As shown in Panel B, pericarditis increased both atrial fibrosis and mass while EV treatment limited the effect of pericarditis on atrial fibrosis and mass. These effects were attributable to the anti-fibrotic effect of EV treatment on atrial fibroblast proliferation profiled using in-vitro cultures exposed to pro-fibrillatory stimuli (i.e., IL-6 and TGFβ1). Conclusion: Intramyocardial injection of EVs at the time of open chest surgery may provide a facile acellular strategy to prevent POAF by reducing inflammation and fibrosis.

Repeated propofol exposure-induced neuronal damage and cognitive impairment in aged rats by activation of NF-κB pathway and NLRP3 inflammasome

BackgroundElderly patients receive propofol at regular intervals for sedation during gastrointestinal endoscopy. However, the link between cognition and intermittent propofol exposure remains unclear. Thus, we used aged rats to investigate the effect of propofol on cognition. MethodsThe study included two parts. In the first part, aged (18–20 months old) male Sprague-Dawley rats underwent intermittent intraperitoneal injection of propofol (200 mg/kg) or intralipid, every 9 days or once a day. In the second part, some aged rats received intraperitoneal injection of Bay 11-7082 (1 mg/kg), a specific inhibitor of NF-κB, 30 min before propofol injection. Memory tests were performed to evaluate cognition 24 h after the entire treatment. The hippocampal neuronal damage was assessed by TUNEL staining. The hippocampal levels of p-NF-κB p65, NLRP3, caspase-1 p20, and cleaved caspase-3 were detected by western blotting. The hippocampal and serum levels of IL-1β, IL-6, and TNF-α were evaluated using ELISA. ResultsThere were no differences in the behavioral tests, hippocampal neuronal damage, and neuroinflammation between groups given intralipid and propofol treatment every 9 days. However, repeated propofol treatment once a day promoted activation of NF-κB and the NLRP3 inflammasome, inducing cognitive impairment and neuroinflammation. Interestingly, pretreatment with Bay-11-7082 not only inhibited NF-κB/NLRP3 inflammasome activation, but also attenuated neuronal damage and cognitive dysfunction in aged rats exposed to daily propofol treatment. ConclusionsIntermittent propofol treatment every 9 days may be safe for aged rats. However, propofol treatment once a day could impair the cognition of aged rats, partly through the activation of the NF-κB pathway and NLRP3 inflammasome, which may be a potential targets for the treatment of cognitive impairment in elderly patients.

High efficacy, rapid onset nanobiolosomes of sildenafil as a topical therapy for erectile dysfunction in aged rats.

Developing topical sildenafil for local treatment of erectile dysfunction has been of great interest in pharmaceutical research. Sildenafil citrate (SC) exhibited a well-documented success for treatment of several types of erectile dysfunction. However, its oral use is limited by serious adverse effects, poor bioavailability, delayed onset, and drug-drug interactions. This work is the first to design and assess sildenafil-loaded bilosomes for topical local treatment of erectile dysfunction. Different sildenafil-loaded bilosomes were prepared and characterized. Permeability of selected formulations was conducted through full-thickness human skin. Optimized bilosomes integrating sodium tauroglycocholate (STGC) showed spherical shape with good particle size (133nm), high zeta potential (-53.6mV) and high entrapment efficiency (87.45%). Ex-vivo permeability study revealed that about 39% of the applied dose permeated within 15min. Furthermore, in-vivo appraisal of therapeutic efficacy was performed using aged male Sprague-Dawley rats. After single application of 2mg/kg sildenafil loaded in STGC-bilosomes, behavioral and biochemical evaluation was carried out. Behavioral assessment recorded an increased rats' potency manifested as 2 folds increase in intromission frequency and intromission ratio compared to untreated group. That was accompanied by significant increase in cGMP concentration in corpora cavernosa (P<0.0001) confirming increased potency. In conclusion, STGC-bilosomes could provide topical treatment of impotence with 20% of the oral dose and fast onset of action (10min).

Heterocyclic modafinil analogue CE-123 as novel improves spatial memory in hole-board task of aged male Sprague-Dawley rats

Heterocyclic modafinil analogue CE-123 as novel improves spatial memory in hole-board task of aged male Sprague-Dawley rats

Long-Chain Fatty Acids and Inflammatory Markers Coaccumulate in the Skeletal Muscle of Sarcopenic Old Rats.

Obesity and inflammation are reportedly associated with the pathogenesis of sarcopenia, which is characterized by age-related loss of skeletal muscle mass. Intramuscular fat deposits have been found to compromise muscle integrity; however, the relevant fat compounds and their roles as mediators of muscular inflammation are not known. The aim of this study was to identify potential correlations between inflammation markers and lipid compounds that accumulate in the quadriceps muscle of previously described Sprague-Dawley (SD) rat model for high-fat diet- (HFD-) induced muscle loss. Six-month-old SD rats were continuously fed a control (CD) or HFD until the age of 21 months. Magnetic resonance imaging (MRI) revealed a significant decline in muscle cross-sectional area in male SD rats as a result of HFD, but not in female rats. Here, we developed a new procedure to quantitatively identify and classify the fatty acid methyl esters (FAMEs) in rats' quadriceps muscles from our former study using gas chromatography-mass spectrometry (GC-MS). Fatty acid analysis revealed accumulation of octadecadienoic (linoleic acid), octadecanoic (stearic acid), and octadecenoic (vaccenic acid) acids exclusively in the quadriceps muscles of male rats. The designated fatty acids were mainly incorporated into triacylglycerols (TAGs) or free fatty acids (FFAs), and their proportions were significantly elevated by consumption of a HFD. Furthermore, the number of resident immune cells and the levels of the chemokines RANTES, MCP-1, and MIP-2 were significantly increased in quadriceps muscle tissue of HFD-fed male, but not female rats. Together, HFD-induced muscle loss in aged male SD rats is associated with greater deposits of long-chain fatty acid esters and increased levels of the inflammatory markers RANTES, MCP-1, and MIP-2 in skeletal muscle tissue. This trend is further reinforced by long-term consumption of a HFD, which may provoke synergistic crosstalk between long-chain fatty acids and inflammatory pathways in sarcopenic muscle.

The effects of vitamin-rich carbohydrate pretreatment on the surgical stress response and S-100\u03b2 after splenectomy in elderly rats

BackgroundPreoperative oral carbohydrates has been suggested to attenuate insulin resistance and decrease postoperative complications. In this study, a vitamin-rich carbohydrate beverage was administered before surgery in an animal model to investigate its effects on the surgical stress response and S-100β levels.MethodsThirty aged male Sprague-Dawley rats were randomly assigned to three groups: control group (n = 6), fasting group (n = 12), and carbohydrate-treated group (CHO group, n = 12). Rats in the control group were not given any treatment. Rats in the fasting group received splenectomy after 12 h of fasting. In the CHO group, rats were given 5 ml of vitamin-rich carbohydrate by gavage 2 h before surgery. Fasting plasma glucose, insulin, insulin resistance (HOMA-IR index, IRI), the S-100β protein level, and the inflammatory mediators IL-1β, IL-6 and TNF-α were assessed after surgery (postoperative day (POD) 1 and 3).ResultsPostoperative insulin resistance was significantly greater in the fasting group than in the control and CHO group. The median plasma S-100β level was significantly higher in the fasting group than in the control and CHO groups on POD 1. The median plasma IL-1β level was significantly lower in the CHO group than in the fasting group on POD 1; however, no other differences in the concentrations of immunological biomarkers of stress were found between the fasting group and the CHO group.ConclusionsVitamin-rich carbohydrate pretreatment attenuated the metabolic aspect of the surgical stress response and decreased the level of plasma S-100β, which may decrease the risk of postoperative complications in elderly rats.

Neuroprotective potential of GDF11 in experimental intracerebral hemorrhage in elderly rats

The occurrence of intracerebral hemorrhage (ICH) costs long-standing neurologic deficits in ICH survivors, elderly ones in particular. Recent researches have proved rejuvenating effect of Growth Differentiation Factor 11 (GDF11) in improving multiple systemic diseases on old individuals. Thus, we designed this study to explore the neuroprotective effect and mechanisms of GDF11 in elderly ICH. 45 aged male Sprague-Dawley (SD) rats were randomly divided into sham + vehicle, ICH + vehicle and ICH + rGDF11 groups. ICH models were induced via injection of autologous whole blood into right basal ganglia of rats. ICH rats were given a daily injection of either recombinant (r) GDF11 at 0.1 mg/kg or vehicle for 28 days prior to operation and continued till the experiment completed. Neurological deficits, brain edema, cell apoptosis, microglial activation and heme oxygenase-1 (HO-1) positive cells were compared among each group. In addition, cytochrome c release, mitochondrial calcium buffering capacity and ATP level were monitored to explore the level of mitochondrial injury. Seen in the result, behavior disorders, severe perihematomal edema, inflammation, apoptosis, oxidative stress and mitochondria damage indicated a significant increase in ICH + vehicle group. While in ICH + rGDF11 group, administration of rGDF11 successfully reduced neurological deficits and alleviated ICH-induced edema, inflammation, apoptosis, oxidative stress, and mitochondria damage in perihematomal tissues. Collectively, our study showed that GDF11 ameliorated ICH-induced neurological deficits in elderly individuals via reducing perihematomal edema, apoptosis, inflammatory reaction, oxidative stress and improving mitochondrial dysfunction, indicating neuroprotective effect of GDF11 in elderly ICH.

Trimetazidine and l‑carnitine prevent heart aging and cardiac metabolic impairment in rats via regulating cardiac metabolic substrates.

This study aimed to investigate the effects of trimetazidine and l‑carnitine on heart aging and cardiac metabolism in the natural aging rats and explore the possible mechanism regarding the regulation of cardiac metabolic substrates. A total of 28 young (2-month-old) and 28 aged (14-month-old) male Sprague-Dawley rats were randomly allocated to the following groups: young control (YC, n = 8), young trimetazidine (YT, n = 10), young l‑carnitine (YL, n = 10), aging control (AC, n = 8), aging trimetazidine (AT, n = 10), and aging l‑carnitine (AL, n = 10). All rats were intragastrically treated with saline, trimetazidine, or l‑carnitine for 4 weeks. Blood sample parameters (MDA, SOD, Glu, TG, TC, LDL-c, HDL-c, AST, ALT, ALP, BUN, Cr, LDH), Echocardiographic paramerters, ATP levels of cardiac apex, cardiac pathology (HE staining and mitochondrial ultrastructures), and cardiac metabolism-related parameters (glucose transporter type-4[GLUT-4], carnitine palmitoyl transferase‑1[CPT-1]) were analyzed in each group. The left ventricular ejection fractions were normal in most groups, with a higher value observed in the AT group than in the AC group. The AC group showed decreased ATP levels of cardiac apex compared with the YC group. But both trimetazidine and l‑carnitine attenuated the aging-induced decrease in ATP levels of cardiac apex. The AC group also showed increased myocardial fiber fragmentations and dissolutions, and interstitial proliferation compared with the YC group. However both trimetazidine and l‑carnitine protected against the aging-induced pathological changes in myocardium. Furthermore, both trimetazidine and l‑carnitine prevented mitochondria of cardiomyocytes from aging-induced injury. Both the AT and AL groups had significantly fewer focal cavitations and higher mitochondrial matrix electron densities than the AC group. GLUT-4 and CPT-1 protein levels were significantly lower while GLUT-4/CPT-1 ratios were higher in aging rats than YC rats. The AT and AL groups had significantly higher GLUT-4 and CPT-1 levels than the AC group, with more significant changes observed in the AT group. Trimetazidine and l‑carnitine may partially improve the age-related changes of rat myocardial metabolisms and heart function via regulating cardiac metabolic substrates, with trimetazidine being superior. Interestingly, they may also reduce cardiac energy generation and impair mitochondrial structures in young rats. These findings suggest that age should be taken as an independent factor during the use of metabolic modulatory drugs in the patients with cardiovascular diseases because it may completely change the effects of drugs.

Effect of isoflurane preconditioning on myocardial ischemia-reperfusion injury induced by antioxidative remodeling in aged rats

Objective To evaluate the effect of isoflurane preconditioning on myocardial ischemia-reperfusion (I/R) injury induced by antioxidative remodeling in aged rats. Methods Fifty-six SPF aged male Sprague-Dawley rats, aged 22-24 months, weighing 420-480 g, were divided into 5 groups by a random number table method: sham operation group (S group, n=16), oxygen free radical scavenger tempol group (T group, n=16), myocardial I/R group (I/R group, n=8), tempol plus myocardial I/R group (TI group, n=8), and tempol plus isoflurane preconditioning plus myocardial I/R group (TII group, n=8). Tempol 125 mg·kg-1·day-1 was intraperitoneally injected for 4 weeks in group T. Myocardial I/R was induced by ligation of anterior descending branch of left coronary artery for 30 min followed by 2-h reperfusion to establish myocardial I/R injury model in group I/R.The model was established after antioxidant treatment in group TI.In group TII, 1.5% isoflurane was inhaled for 30 min followed by 15-min washout, and then the model was established.Animals were sacrificed at the end of reperfusion, and the left ventricle was obtained for determination of the percentage of myocardial infarct size (by TTC staining), glutathione(GSH)and oxidized glutathione(GSSG) concentrations and superoxide dismutase(SOD)activity in S and T groups (by enzyme-linked immunosorbent assay), and expression of Cu/ZnSOD, MnSOD and nitrotyrosine in S and T groups (by Western blot). Results Compared with S and T groups, the percentage of myocardial infarct size was significantly increased in I/R, TI and TII groups (P 0.05), the expression of GSSG and nitrotyrosine was down-regulated, the GSH/GSSG ratio was increased, the activities of total SOD and MnSOD were increased, and the expression of MnSOD was up-regulated in group T (P<0.05). Conclusion Isoflurane preconditioning can reduce myocardial I/R injury induced by antioxidative remodeling in aged rats. Key words: Isoflurane; Antioxidants; Aged; Myocardial reperfusion injury

Caloric restriction improves the redox homeostasis in the aging male rat heart even when started in middle-adulthood and when the body weight is stable

Evidence indicates that maintenance of redox homeostasis is fundamental for cellular longevity. Caloric-restriction (CR) is said to decrease the formation of oxidatively modified cellular macromolecules and improve health. On the other hand, some studies indicate that many CR studies are flawed, because ad libitum fed rats are not well-controlled. Thus, it is claimed that purported beneficial effects of CR could be not due to real CR effect, but due to control animals going obese. Also, it remains to be elucidated whether effects of CR could be observed even when CR is started in mid-adulthood. Male Sprague-Dawley rats were grouped as: non-CR 6-month-old rats (n = 7), 24-month-old rats subjected to 40% CR for 6months between 18th and 24thmonths (n = 8), and non-CR 24-month-old animals (n = 8). We investigated 16 previously validated biomarkers of macromolecular redox homeostasis, ranging from protein and lipid oxidation to glycation and antioxidative capacity. In the present study, the protein, lipid and antioxidant capacity redox homeostasis biomarkers overwhelmingly indicate that, CR, even though not started very early in adulthood, could still offer potential therapeutic effects and it could significantly improve various redox homeostasis biomarkers associated with disease reliably in the heart tissue of aging male Sprague-Dawley rats. Therefore, the effects of CR likely operate through similar mechanisms throughout adulthood and CR seems to have real ameliorative effects on organisms that are not due to confounding factors that come from ad libitum fed rats.

ALDH2 attenuates early-stage STZ-induced aged diabetic rats retinas damage via Sirt1/Nrf2 pathway

AimsAcetaldehyde dehydrogenase 2 (ALDH2) was reported for its protective properties on myocardial damage, stroke and neurodegeneration disease, but the effects and mechanisms of ALDH2 in the modulation of diabetic retinopathy remain unclear. The present study evaluated the protection effects of ALDH2 on streptozocin (STZ)-induced aged diabetic rats retinas damage. Main methods24 aged male diabetic Sprague-Dawley (SD) rats induced by a single intraperitoneal injection of STZ were randomly divided into Alda1-treated group and dimethylsulfoxide (DMSO) group. Rats were intraperitoneally injected with 10 mg/kg ALDH2 activator Alda1 (or DMSO) 3 days before STZ injection and 30 days afterwards. A series of detections on retinal structural, functional and molecular levels were applied at 1 d, 7 d and 30 d after aged diabetic rats model established. Key findingsOptical coherence tomography (OCT) revealed that the thickness of outer nuclear layer (ONL) and whole retinas in Alda1-treated group were thicker than DMSO group. Full field electroretinograms (ffERG) showed a higher amplitude wave (dark-adaptation 3.0 and OPs) in Alda1-treated group. In addition, the levels of retinal tumor necrosis factor (TNF-α) and interleukin-6 (IL-6) from Alda1-treated group were lower whereas superoxide dismutase (SOD) activity was notably higher. Moreover, the expressions of ALDH2, silence information regulation factor 2 related enzyme I (Sirt1) and nuclear factor erythroid 2-related factor 2 (Nrf2) in Alda1-treated group retinas were significantly increased, while the expression of vascular endothelial growth factor (VEGF-α) was dramatically decreased. SignificanceALDH2 could ameliorate early-stage STZ-induced aged diabetic rats retinas damage possibly via increasing Sirt1 and Nrf2 expression.

Effects of Lipoxin A4 Pretreatment on Cognitive Function of Aged Rats after Global Cerebral Ischemia Reperfusion.

The aim of the present study was to investigate the effect of lipoxin A4 (LXA4) pretreatment on cognitive function of aged rats after global cerebral ischemia reperfusion, and to explore its possible mechanism. Thirty-six aged male Sprague-Dawley rats were randomly divided into three groups (n=2 each): sham-operation group (S group), global cerebral ischemia reperfusion group (I/R group) and LXA4-pretreatment group (L group). The rat model of global cerebral ischemia reperfüsion was established by occlusion of the bilateral common carotid artery with hypotension. The cognitive function of rats was determined by a step-down type passive avoidance test and Morris Water Maze test on the third day after reperfUsion. Rats were sacrificed after Water Maze test and the pathological changes of hippocampal CAI region were observed and the related inflammatory mediators were determined. As compared with S group, the escape latency in I/R group was prolonged from the first day to the fifth day, while that in L group was prolonged from the first day to the third day. The retention time in I/R group and L group in the first quadrant was shortened. The reaction time, frequency of reaction mistake and frequency of escape mistake in I/R group increased, and the latent period shortened. The frequency of escape mistake in L group increased, and the damage in the hippocampal CAI region of I/R group and L group was obvious. The levels of S-100β, TNP-α, IL-lβ, IL-10 and NF-κB in I/R group and L group increased. As compared with I/R group, the escape latency in L group was shortened from the first day to the fifth day, and the retention time in the first quadrant prolonged. The reaction time, frequency of reaction mistake and frequency of escape mistake in L group decreased, and the latent period prolonged. The damage in the hippocampal CAI region of L group was alleviated as well. The levels of S-100β, TNP-α, IL-lβ and NF-κB in L group decreased, and those of IL-10 increased. It can be concluded that LXA4 pretreatment can improve the cognitive function in aged rats after global cerebral ischemia reperfusion probably by inhibiting the inflammatory reaction.