scholarly journals STRENGTH TRAINING AND ANABOLIC STEROID DO NOT AFFECT MUSCLE CAPILLARIZATION OF MIDDLE-AGED RATS

2017 ◽  
Vol 23 (2) ◽  
pp. 137-141 ◽  
Author(s):  
Walter Krause Neto ◽  
Eliane Florencio Gama
Keyword(s):  
Anabolic Steroid ◽  
Skeletal Muscles ◽  
Wistar Rats ◽  
Extensor Digitorum Longus ◽  
Aged Rats ◽  
Middle Aged ◽  
Cross Sectional ◽  
Anabolic Agent ◽  
Volumetric Density ◽  
Old Rats

ABSTRACT Introduction: It is generally accepted that the capillary network decreases with advancing age. The combined effect of resistance training (RT) and testosterone still needs to be elucidated. Objective: This study aimed to measure capillary profile of different skeletal muscles of middle-aged rats undergoing RT and administration of exogenous testosterone. Methods: Wistar rats were divided into five experimental groups: control with 13-month-old rats (SC), control with 16-month-old rats (SE), aged rats + anabolic agent (SA), aged rats + RT (T), and aged rats + RT + anabolic agent (TA). Results: For soleus, the SE group presented a decrease in the percentage of capillaries in comparison to SC group. SA, T, and TA groups had increased capillary volume in comparison to SC. As for the extensor digitorum longus (EDL), SA, T, and TA groups demonstrated lower capillary volume and numeric density in comparison to SC and SE. The EDL of the T and TA groups presented 70% less capillaries than soleus. The numerical and volumetric density and capillary ratio by muscle fiber were not statistically altered by any intervention. The cross-sectional area (CSA) of the soleus of the SA, T and TA groups was statistically different from SC group. The soleus CSA was greater in the TA and T groups than in the SC, SE and SA groups, and the EDL CSA was greater in the TA compared to all other groups. The TA group had greater values than the SE, SA, and T groups. Conclusion: The type of intervention used did not affect any variables measured in the capillary profile. However, the use of anabolic steroid and/or RT showed a tendency to decrease the density of capillaries in the EDL.

scholarly journals Regeneration of new fibers in muscles of old rats reduces contraction-induced injury

1999 ◽  
Vol 87 (2) ◽  
pp. 750-756 ◽  
Author(s):  
Steven T. Devor ◽  
John A. Faulkner
Keyword(s):  
Elderly People ◽  
Skeletal Muscles ◽  
Wistar Rats ◽  
Extensor Digitorum Longus ◽  
Muscle Fibers ◽  
Extensor Digitorum ◽  
Lengthening Contractions ◽  
Male Wistar Rats ◽  
Old Rats ◽  
Regenerated Fibers

Skeletal muscles are injured by their own contractions. Compared with muscles in young animals, those in old animals are injured more easily and more severely and regenerate less well afterward. Injection of a myotoxin (bupivacaine) causes complete degeneration of fibers in extensor digitorum longus (EDL) muscles of rats, followed by full regeneration within 60 days. We tested the specific hypothesis that, 3 days after a protocol of pliometric (lengthening) contractions, the newly regenerated muscle fibers in bupivacaine-treated EDL muscles in both young and old rats would show a lesser deficit in maximum force and fewer damaged fibers than muscles in nontreated EDL muscles. The treated and nontreated EDL muscles of young and old male Wistar rats were administered a protocol of 225 pliometric contractions and were evaluated 3 days afterward, when morphological damage to muscle fibers is most severe. In treated compared with nontreated EDL muscles of both young and old rats, the force deficit and the number of damaged fibers were each reduced by ∼75%. We conclude that newly regenerated fibers in muscles of young and old animals are resistant to injury and that maintenance of newly regenerated fibers by conditioning may prevent inadvertent damage, particularly in muscles of elderly people.

scholarly journals Age-Related Effects on Right Femoral Bone of Male Wistar Rats: A Morphometric and Biomechanical Study

2021 ◽  
Author(s):  
Sheila Martins Puelker ◽  
Sonia Regina Ribeiro de Castro ◽  
Romeu Rodrigues de Souza ◽  
Laura Beatriz Mesiano Maifrino ◽  
Ricardo Aparecido Baptista Nucci ◽  
...  
Keyword(s):  
Cortical Thickness ◽  
Wistar Rats ◽  
Female Rats ◽  
Male Rats ◽  
Aged Rats ◽  
Femoral Bone ◽  
Middle Aged ◽  
Left Femur ◽  
Bone Stiffness ◽  
The Right

Abstract Introduction Study of the variations of bone characteristics with age in different animal models is important to design musculoskeletal studies. Thus, this study aimed to evaluate the bone mass, dimensions, and biomechanical parameters of the femur in young, middle-aged, and aged Wistar rats. Materials and Methods Thirty male rats (Rattus norvegicus) were divided in three groups (n = 10 per group)—3-month-old young rats, 12-month-old middle-aged rats, and 18-months-old aged rats. The right femurs were subjected sequentially to morphometric study (bone weight, cortical thickness) and biomechanical tests (maximum resistance strength and bone stiffness). Results We observed a significant increase in femur histological (cortical thickness) and biomechanical (maximum strength and bone stiffness) parameters with aging when compared with young animals. Conclusions With the advancing age, the right femoral bone of middle-aged and old animals had greater variations when compared with young animals. However, further studies with the aid of a comparison between right and left femur and other long bones in both male and female rats are needed to corroborate with our findings.

scholarly journals Effects of aging on mineralocorticoid-induced salt appetite in rats

2013 ◽  
Vol 305 (12) ◽  
pp. R1498-R1505 ◽  
Author(s):  
Robert L. Thunhorst ◽  
Terry G. Beltz ◽  
Alan Kim Johnson
Keyword(s):  
Saline Solution ◽  
Brown Norway ◽  
Salt Appetite ◽  
Aged Rats ◽  
Middle Aged ◽  
Renal Handling ◽  
Saline Preference ◽  
Old Rats ◽  
Middle Aged Adult ◽  
Effects Of Aging

This work examined the effects of age on salt appetite measured in the form of daily saline (i.e., 0.3 M NaCl) drinking in response to administration of deoxycorticosterone acetate (DOCA; 5 mg/kg body wt) using young (4 mo), “middle-aged” adult (12 mo), and old (30 mo) male Brown Norway rats. Water and sodium intakes, excretions, and balances were determined daily. The salt appetite response was age dependent with “middle-aged” rats ingesting the most saline solution followed in order by young and then old rats. While old rats drank the least saline solution, the amounts of saline ingested still were copious and comprise an unambiguous demonstration of salt appetite in old rats. Middle-aged rats had the highest saline preference ratios of the groups under baseline conditions and throughout testing consistent with an increased avidity for sodium taste. There were age differences in renal handling of water and sodium that were consistent with a renal contribution to the greater saline intakes by middle-aged rats. There was evidence of impaired renal function in old rats, but this did not account for the reduced saline intakes of the oldest rats.

scholarly journals The Effects of Calcium-β-Hydroxy-β-Methylbutyrate on Aging-Associated Apoptotic Signaling and Muscle Mass and Function in Unloaded but Nonatrophied Extensor Digitorum Longus Muscles of Aged Rats

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Brian T. Bennett ◽  
Junaith S. Mohamed ◽  
Stephen E. Alway
Keyword(s):  
Muscle Mass ◽  
Satellite Cells ◽  
Muscle Function ◽  
Extensor Digitorum Longus ◽  
Cross Sectional Area ◽  
Extensor Digitorum ◽  
Aged Rats ◽  
Sectional Area ◽  
Cross Sectional ◽  
Apoptotic Signaling

Beta-hydroxy-beta-methylbutyrate (HMB), a naturally occurring leucine metabolite, has been shown to attenuate plantar flexor muscle loss and increase myogenic stem cell activation during reloading after a period of significant muscle wasting by disuse in old rodents. However, it was less clear if HMB would alter dorsiflexor muscle response to unloading or reloading when there was no significant atrophy that was induced by unloading. In this study, we tested if calcium HMB (Ca-HMB) would improve muscle function and alter apoptotic signaling in the extensor digitorum longus (EDL) of aged animals that were unloaded but did not undergo atrophy. The EDL muscle was unloaded for 14 days by hindlimb suspension (HS) in aged (34-36 mo.) male Fisher 344×Brown Norway rats. The rats were removed from HS and allowed normal cage ambulation for 14 days of reloading (R). Throughout the study, the rats were gavaged daily with 170 mg of Ca-HMB or water 7 days prior to HS, then throughout 14 days of HS and 14 days of recovery after removing HS. The animals’ body weights were significantly reduced by ~18% after 14 days of HS and continued to decline by ~22% during R as compared to control conditions; however, despite unloading, EDL did not atrophy by HS, nor did it increase in mass after R. No changes were observed in EDL twitch contraction time, force production, fatigue resistance, fiber cross-sectional area, or markers of nuclear apoptosis (myonuclei + satellite cells) after HS or R. While HS and R increased the proapoptotic Bax protein abundance, BCL-2 abundance was also increased as was the frequency of TUNEL-positive myonuclei and satellite cells, yet muscle mass and fiber cross-sectional area did not change and Ca-HMB treatment had no effect reducing apoptotic signaling. These data indicate that (i) increased apoptotic signaling preceded muscle atrophy or occurred without significant EDL atrophy and (ii) that Ca-HMB treatment did not improve EDL signaling, muscle mass, or muscle function in aged rats, when HS and R did not impact mass or function.

Effects of Chinese Herbal Prescriptions on Copulatory Activity in Aged Male Rats: A Preliminary Study

1998 ◽  
Vol 26 (01) ◽  
pp. 83-90 ◽  
Author(s):  
Hui-Chiu Chang ◽  
Sheng-l Lue ◽  
Chin Hsu ◽  
Hseng-Kuang Hsu ◽  
Ching-Feng Weng ◽  
...  
Keyword(s):  
Serum Testosterone ◽  
Copulatory Behavior ◽  
Male Rats ◽  
Aged Rats ◽  
Middle Aged ◽  
Promotional Effect ◽  
Before And After ◽  
Copulatory Activity ◽  
Old Rats ◽  
Herbal Prescription

Four herbal prescription medicines, Chi-Pao-Mei-Jan-Tan, Gui-Fu-Ba-Wei-Wan, Huan-Shao-Tan; and San Tsai-Feng-Sui-Tan, were tested for their effects on sexual behavior in aged rats. Crude liquid extracts of these herbs were administered to the rats daily through oral tubing for 14 days. All four herbal prescriptions showed some effects in restoration of mount and intromission behaviors, but there was no effect on restoration of ejaculation in 26 month old rats that had exhibited no copulatory activity (no mount, intromission and ejaculation) previously. The effects of Chi-Pao-Mei-Jan-Tan were further tested in 26 month old rats with low mount and intromission activities but without ejaculation behavior, and in 15 month old rats (middle-age group) that showed normal mount and intrornission behavior but no ejaculation activity. Chi-Pao-Mei-Jan-Tan was effective in improving the frequency of both mount and intromission, but failed to restore the ejaculation activity of the old rats with low mount and intromission behaviors. It was, however, very effective in restoration of ejaculation activity in middle-aged rats that exhibited normal mount and intromission behaviors. Serum testosterone (T) levels of Chi-Pao-Mei-Jan- Tan in tested old and middle-aged rats were determined by radioimmunoassay, and showed no difference before and after treatment. Our findings demonstrated that the four herbal prescriptions had some effects in restoration of mount and intromission behaviors, but not ejaculation activity in old rats, and that Chi-Pao-Mei-Jan-Tan was very effective in restoration of ejaculation activity in middle-aged rats. The promotional effect of Chi-Pao-Mei-Jan-Tan on copulatory behavior was not correlated with serum T levels.

scholarly journals Effects of β-adrenergic receptor agonists on drinking and arterial blood pressure in young and old rats

2011 ◽  
Vol 300 (4) ◽  
pp. R1001-R1008 ◽  
Author(s):  
Robert L. Thunhorst ◽  
Connie L. Grobe ◽  
Terry G. Beltz ◽  
Alan Kim Johnson
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Adrenergic Receptors ◽  
Adrenergic Receptor ◽  
Aged Rats ◽  
Middle Aged ◽  
Young Rats ◽  
Arterial Blood ◽  
Age Related ◽  
Old Rats

These experiments examined water-drinking and arterial blood pressure responses to β-adrenergic receptor activation in young (4 mo), “middle-aged” adult (12 mo), and old (29 mo) male rats of the Brown-Norway strain. We used isoproterenol to simultaneously activate β1- and β2-adrenergic receptors, salbutamol to selectively activate β2-adrenergic receptors, and the combination of isoproterenol and the β2-adrenergic receptor antagonist ICI 118,551 to stimulate only β1-adrenergic receptors. Animals received one of the drug treatments, and water drinking was measured for 90 min. About 1 wk later, animals received the same drug treatment for measurement of arterial blood pressure responses for 90 min. In some rats, levels of renin and aldosterone secretion in response to isoproterenol or salbutamol were measured in additional tests. Old and middle-aged rats drank significantly less after isoproterenol than did young rats and also had greater reductions in arterial blood pressure. Old and middle-aged rats drank significantly less after salbutamol than did young rats, although reductions in arterial blood pressure were equivalent across the ages. The β2-adrenergic antagonist ICI 118,551 abolished drinking after isoproterenol and prevented most of the observed hypotension. Renin secretion after isoproterenol and salbutamol was greater in young rats than in middle-aged rats, and wholly absent in old rats. Aldosterone secretion was reduced in old rats compared with young and middle-aged rats after treatment with isoproterenol, but not after treatment with salbutamol. In conclusion, there are age-related differences in β-adrenergic receptor-mediated drinking that can be explained only in part by age-related differences in renin secretion after β-adrenergic receptor stimulation.

Anatomic capillarization is maintained in relative excess of fiber oxidative capacity in some skeletal muscles of late middle-aged rats

2004 ◽  
Vol 96 (6) ◽  
pp. 2257-2264 ◽  
Author(s):  
Russell T. Hepple ◽  
Janis E. Vogell
Keyword(s):  
Young Adult ◽  
Skeletal Muscles ◽  
Oxidative Capacity ◽  
Brown Norway ◽  
Aged Rats ◽  
Middle Aged ◽  
White Region ◽  
Wide Range ◽  
The Individual ◽  
Gastrocnemius Muscles

The anatomic size of the capillary-to-fiber (C/F) interface plays an important role in O2 flux from blood to tissue by determining the surface area available for diffusion and is maintained in relative proportion to fiber mitochondrial volume across a wide range of muscle aerobic capacity. In the present study, we examined an estimate of the anatomic size of the C/F interface [the quotient of the individual C/F ratio and fiber perimeter, C/F perimeter exchange (CFPE) index] and fiber oxidative capacity in different skeletal muscles, or muscle regions, to test the hypothesis that capillarization would be maintained in relative excess of reduced fiber oxidative capacity in aged muscles. The right gastrocnemius, plantaris, and soleus muscles from young adult (8 mo old) and late middle-aged (28–30 mo old) Fischer 344 × Brown Norway F1 hybrid rats were excised for evaluation of flux through electron transport chain complexes I–III and/or morphometric estimation of capillarization. Muscle mass was lower in the gastrocnemius muscles of the older animals (2,076 ± 32 vs. 1,825 ± 47 mg in young adult vs. late middle-aged, respectively; mean ± SE) but not the plantaris or soleus muscles. Fibers were smaller in the white region of gastrocnemius muscles but larger in the red region of gastrocnemius muscles of the older animals. There was no difference in the number of capillaries around a fiber, the individual C/F ratio, or the CFPE index between groups for any muscle/region, whereas flux through complexes I–III was reduced by 29–43% in late middle-aged animals. Thus the greater quotient of indexes of anatomic capillarity (individual C/F ratio or CFPE index) and fiber oxidative capacity in soleus and the white region of gastrocnemius muscles, but not in the red region of gastrocnemius muscles of the older animals, shows that anatomic capillarity is maintained in relative excess of oxidative capacity in some muscle regions in late middle-aged rats.

scholarly journals Hypotension- and osmotically induced thirst in old Brown Norway rats

2009 ◽  
Vol 297 (1) ◽  
pp. R149-R157 ◽  
Author(s):  
Robert L. Thunhorst ◽  
Terry G. Beltz ◽  
Alan Kim Johnson
Keyword(s):  
Arterial Pressure ◽  
Brown Norway ◽  
Aged Rats ◽  
Middle Aged ◽  
Young Rats ◽  
Age Related ◽  
Cellular Dehydration ◽  
Old Rats ◽  
Middle Aged Adult ◽  
Norway Rats

Compared to young cohorts, old rats drink less water in response to several thirst-inducing stimuli. In these experiments, we characterized water drinking in response to hypotension and cellular dehydration in young (4 mo), middle-aged adult (12 mo) and old (29–30 mo) male Brown Norway rats. We injected the vasodilator, minoxidil as an intravenous bolus in a range of doses (0–20 mg/kg), so that drinking responses could be compared at equivalent reductions of arterial pressure. Old rats had greatly diminished reflex tachycardia and became significantly more hypotensive after minoxidil compared with young and middle-aged rats. When compared at equivalent reductions of arterial pressure, old rats drank one-third as much as middle-aged rats, and one-fifth as much as young rats. In addition, there were age-related deficits in drinking in response to a range of administered loads of sodium (0.15–2 M NaCl, 2 ml/100 g body wt). Urinary excretion of water and sodium in response to the loads was equivalent across ages. Both middle-aged and old rats were less able than young rats to repair their water deficits after sodium loading, attributable almost entirely to their reduced drinking responses compared with young rats. Lastly, age-related declines in drinking appeared to be more severe in response to hypotension than in response to cellular dehydration.

scholarly journals Effect of β-alanine supplementation on carnosine and histidine content in the hippocampus of 14-month-old rats

2019 ◽  
Vol 44 (10) ◽  
pp. 1112-1115 ◽  
Author(s):  
Jay R. Hoffman ◽  
John A. Rathmacher ◽  
Jennifer Robinson ◽  
Yftach Gepner ◽  
Hagit Cohen
Keyword(s):  
Male Rats ◽  
Aged Rats ◽  
Middle Aged ◽  
Old Rats

Carnosine and histidine content in the hippocampus of 14-month-old male rats was examined following 30 days of β-alanine supplementation. All animals were provided identical diets; however, 100 mg of β-alanine was mixed with glucomannan (80:20 blend) in the water of β-alanine supplemented animals. Hippocampal carnosine content was significantly greater (p = 0.005) for β-alanine compared with control, while no differences (p = 0.438) were noted in histidine content between groups. Results provide initial evidence that β-alanine supplementation increases carnosine content in the hippocampus of middle-aged rats, without compromising histidine content. β-Alanine supplementation increases hippocampal carnosine content without compromising histidine content in middle-aged rats.

Age-related changes in the diurnal rhythm of CRH gene expression in the paraventricular nuclei

1996 ◽  
Vol 270 (2) ◽  
pp. E238-E243 ◽  
Author(s):  
A. Cai ◽  
P. M. Wise
Keyword(s):  
Diurnal Rhythm ◽  
Adrenocorticotropic Hormone ◽  
Age Groups ◽  
Aged Rats ◽  
Middle Aged ◽  
Paraventricular Nuclei ◽  
Age Related ◽  
Old Rats ◽  
Two Age Groups

A circadian rhythm secretion of corticotropin-releasing hormone (CRH) is thought to regulate the circadian pattern of secretion of adrenocorticotropic hormone and corticosterone. We have previously reported that the amplitude of the diurnal rhythm of serum corticosterone concentrations decreases in 17- to 20-mo-old rats. In the present experiment, we tested whether an age-related alteration in the daily rhythm and/or level of CRH mRNA in the paraventricular nuclei (PVN) occurs during middle age. Groups of young and middle-aged animals were killed at several times of day. We assessed the level of CRH mRNA in the PVN and dorsal medial subdivision of the PVN using in situ hybridization. In young rats, CRH mRNA expression exhibited a diurnal rhythm in the dorsal medial PVN. The same trend was observed in the entire medial PVN. In middle-aged rats, no rhythm was detected in either region. The overall average level of CRH mRNA was not different between these two age groups. These findings suggest that changes in the suprachiasmatic nucleus or in its ability to entrain neuroendocrine outputs occur relatively early during the aging process.

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