Voluntary stand-up physical activity enhances endurance exercise capacity in rats

Involuntary physical activity induced by the avoidance of electrical shock leads to improved endurance exercise capacity in animals. However, it remains unknown whether voluntary stand-up physical activity (SPA) without forced simulating factors improves endurance exercise capacity in animals. We examined the eff ects of SPA on body weight, cardiac function, and endurance exercise capacity for 12 weeks. Twelve male Sprague-Dawley rats (aged 8 weeks, n=6 per group) were randomly assigned to a control group (CON) or a voluntary SPA group. The rats were induced to perform voluntary SPA (lifting a load equal to their body weight), while the food height (18.0 cm) in cages was increased progressively by 3.5 every 4 weeks until it reached 28.5 cm for 12 weeks. The SPA group showed a lower body weight compared to the CON group, but voluntary SPA did not affect the skeletal muscle and heart weights, food intake, and echocardiography results. Although the SPA group showed higher grip strength, running time, and distance compared to the CON group, the level of irisin, corticosterone, genetic expression of mitochondrial biogenesis, and nuclei numbers were not affected. These findings show that voluntary SPA without any forced stimuli in rats can eff ectively reduce body weight and enhance endurance exercise capacity, suggesting that it may be an important alternative strategy to enhance endurance exercise capacity.

Inter- and intra-breed comparative study of sperm motility and viability in Iberian and Duroc boar semen during long-term storage in MR-A and XCell extenders.

During boar semen liquid preservation, extender is one of the factors that influence storage tolerance of spermatozoa. However, there are few studies about intra-breed variation in the preservation of semen quality during storage in different extenders. Similarly, boar breed is generally not considered a possible factor influencing variation in the semen storage tolerance in a particular extender. The aim of this study was to compare boar semen storage potential, in terms of the ability to maintain sperm viability and motility, of two currently used long-term extenders, MR-A and XCell. Extended semen from two breeds, Iberian and Duroc that had been stored at 17°C for up to 7 days was used. Intra- and inter-breed effect was studied. On Days 1, 4 and 7 (Day 0=day of semen collection), motility parameters and the percentage of total motile sperm and progressively motile sperm using a CASA system was evaluated. Viability (SYBR-14/PI) was evaluated by flow cytometry. Within each breed and for each storage day, there were differences between extenders, although semen tolerance to preservation was more influenced by the extender in the Iberian than in the Duroc breed. Neither breed nor extender influenced the percentage of viable spermatozoa during the storage time. Moreover, differences in motility parameters were observed between breeds, although the differences were greater when the XCell extender was used. In conclusion, both extender and breed influence motility characteristics of liquid-stored boar semen, so both aspects have to be considered in the design of comparative studies about stored boar semen quality from different breeds or with different extenders. Further studies are needed to corroborate these findings.

The effect of melatonin on the quality of extended boar semen after long-term storage at 17 °C.

Melatonin (MLT) is an efficient antioxidant that protects cells and tissues and initiates a host of receptor-mediated effects. In order to enhance the life span of refrigerated boar semen, our aim was to evaluate the effects of addition of 1 µM MLT to commercially produced pig semen (33 seminal doses from 14 boars) that had been preserved at 17 °C for 7 days. Samples without MLT served as controls. On Days 1, 4 and 7, we evaluated motility parameters and the percentage of total motile and progressively motile spermatozoa by a computer-aided sperm analysis system. Viability (SYBR-14/PI), acrosomal status (FITC-PNA/PI), membrane fluidity (M-540/YoPro-1) and mitochondrial membrane potential status (JC-1) were evaluated by flow cytometry. MLT treatment significantly enhanced the percentage of static spermatozoa after 7 days of storage and significantly reduced the percentage of progressively motile spermatozoa on Day 7. The velocity characteristics (VCL, VSL and VAP) were significantly higher for MLT-treated samples on Day 1 and were their lowest on Day 7. With regard to flow cytometry results, the percentage of viable spermatozoa with an intact acrosome was higher in MLT samples throughout the entire storage period. In addition, there was a significantly higher proportion of live spermatozoa on Day 7 in the samples that had not been treated with MLT. The proportion of spermatozoa showing a high mitochondrial membrane potential remained at similar levels (P > 0.05) throughout the trial. Although the findings of the present study revealed that 1 µM MLT increased the proportion of live sperm with an intact acrosome, this treatment did not enhance the spermatic quality of refrigerated boar semen.

G protein kinase 4gammaA142V overexpression induced hypertension by downregulating D1 receptors in transgenic mice / 中华心血管病杂志

<p><b>OBJECTIVE</b>Abnormalities in dopamine production and receptor function have been described in human essential hypertension and rodent models of genetic hypertension. We investigated the role of G protein kinase (GRK) 4gamma in essential hypertension in GRK4gamma mutant A142V transgenic mice.</p><p><b>METHODS</b>Blood pressure, renal sodium excretion, D(1) receptor protein expression and phosphorylation were measured in GRK4gammaA142V transgenic mice and control mice. Moreover, the effects of GRK4 inhibition by antisense oligonucleotides on D(1) receptor expressions were determined in HK-2 cells.</p><p><b>RESULTS</b>As compared with their control mice, GRK4gammaA142V transgenic mice had higher blood pressure, lower D(1) receptor expression (0.6 +/- 0.2 vs. 1.5 +/- 0.2, P < 0.05), higher D(1) receptor phosphorylation [(65 +/- 7) DU vs. (35 +/- 7) DU, P < 0.05] in renal cortical membranes and the diuretic and natriuretic effects after stimulation of renal D(1) receptor were impaired in GRK4gammaA142V transgenic mice. Inhibition of GRK4 expression (0.60 +/- 0.10 vs. 1.30 +/- 0.09, P < 0.05) by GRK4 antisense oligonucleotides upregulated D(1) receptor expression (1.5 +/- 0.2 vs. 0.8 +/- 0.1, P < 0.05) in HK-2 cells.</p><p><b>CONCLUSIONS</b>Our results show that GRK4gammaA142V overexpression induced hypertension is mediated by dowregulated renal D(1) receptor expressions in GRK4gammaA142V transgenic mice.</p>

Hypertension in D3 dopamine receptor deficient mice / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the mechanisms by which hypertension occurs in D(3) dopamine receptor null mice (D(3)-/-).</p><p><b>METHODS</b>Several parameters, including blood pressure, renal sodium excretion, D(3) receptor protein and mRNA expression, plasma renin activity, norepinephrine concentration and AT(1) receptor expression were checked in D(3)-/- mice and their littermate wild type mice (D(3)+/+). Moreover, the vasorelaxant effect of D(3) receptor stimulation was measured with ex-vivo mesenteric artery isolated from Wistar-Kyoto rats.</p><p><b>RESULTS</b>Blood pressure was higher in D(3)-/- mice compared with that in D(3)+/+ mice, salt-loading had no effect on blood pressure in both groups, at the last period, sodium excretion was lower in D(3)-/- mice as compared with D(3)+/+ mice, renal renin activity and AT(1) receptor expression were higher in D(3) -/- [corrected] mice than in D(3) +/+ [corrected] mice. In contrast, no difference of renal norepinephrine was found in two groups. When using angiotensin II subtype-1 receptor antagonist, the systolic blood pressure declined for a longer duration in mutant mice than in wild-type mice. Vaso-relaxation was found in ex-vivo isolated mesenteric artery when D(3) receptor was stimulated.</p><p><b>CONCLUSIONS</b>Elevation of blood pressure in D(3)-/- mice might be related with impaired renal sodium excretion and vaso-relaxation in resistance artery.</p>

Development of meat and carcass quality characteristics in Iberian pigs reared outdoors.

A study of age-related changes in carcass traits and meat quality characteristics of Longissimus dorsi (LD) and Biceps femoris (BF) of free-ranged Iberian pigs was carried out to check whether the slaughter age used in the traditional management system of Iberian pigs is adequate. There was a great increase in live and carcass weight during fattening, principally due to an increase in fat deposition, as could be deduced from the percentage of dissectible fat and the backfat thickness. However, intramuscular fat in LD and BF showed only slight changes during the fattening. Myoglobin content tended to increase throughout lifetime in both muscles, whereas water-holding capacity decreased in intermediate ages and showed the highest values in the oldest animals. Total collagen content did not vary during lifetime; on the other hand, insoluble collagen increased from 7 to 77% of total collagen. It can be concluded that the traditional management system of Iberian pigs can be improved by fattening the pigs at a younger age, without negative consequences on the meat quality.

Histomorphometric analysis of the omasum of sheep during development.

Histomorphometric and scanning electron microscopic analyses were performed on 74 embryos and fetuses and 20 sheep (early postnatal to adult age). Histologic differentiation of the omasum took place at 33 days of fetal life, with the appearance of first-order laminae. Second-, third-, and fourth-order laminae appeared at 39, 50, and 59 days, respectively. Neutral mucopolysaccharides first appeared in epithelial cells at 46 days of fetal life, decreasing quantitatively until birth, before subsequently stabilizing in postnatal life. Acid mucopolysaccharides, mucins, and mucoid compounds were not detected. Growth curves and formulas were constructed for each tissue layer. Initial tests involved multiplicative (y = axb), exponential (y = EXP [a + bx]), linear (y = a + bx), and polynomial models (y = a + bx + cx2 + dx3).

Craniofacial angle in dolicho-, meso- and brachycephalic dogs: radiological determination and application.

Observations on craniofacial axes and angles were made on fifty dogs belonging to five breeds, by means of radiological techniques (lateral radiographs) and biostatistical methods. The craniofacial angles were found to be 25-26 degrees (greyhound), 19-20 degrees (pointer), 20-21 degrees (German shepherd), 13-14 degrees (boxer) and 9-10 degrees (Pekinese). Shortening of the head in brachycephalic dogs implies a more perpendicular development of the cranium relative to the facial axis. The possible application of these data in the determination of morphological types in many fields is discussed.

Histomorphometric analysis of the reticulum of the sheep during development.

Histomorphometric and scanning electron microscopic analysis were performed on 74 embryos and foetuses and on 20 sheep (early post-natal to adult age). Histodifferentiation of the reticulum took place at 33 days of foetal life. Reticular ribs were observed as evaginations of the epithelial stratum germinativum at 64 days. Neutral mucopolysaccharides first appeared in epithelial cells at 46 foetal days, thereafter to decrease gradually in number, subsequently stabilising in postnatal life. Acid mucopolysaccharides, mucins and mucoid compounds were not detected. Growth curves and formulae were constructed for each tissue layer. Initial test involved multiplicative (y = axb), linear (y = a+bx) and polynomial model (y = a+b+cx2+dx3).

[Mathematical models applied to the growth of the ovine stomach during intrauterine life]. / Modelos matemáticos aplicados al crecimiento gástrico ovino durante la vida intrauterina.

One hundred forty four ovine embryos and feti were used in an investigation to determine mathematical models describing the histomorphometric growth of tissues and compartments of the ruminant stomach. The results indicate that during prenatal life the diameter of the gastric chambers increase more slowly than the length. The tissue layers of the gastric walls, particularly the muscular tunic of all compartments demonstrated a uniform tendency toward more rapid development than the compartment walls proper.

Histomorphometric analysis of the abomasum of the sheep during development.

Histomorphometric analyses were carried out on 64 embryos and fetuses and on 20 sheep (early postnatal to adult age). Histodifferentiation of the abomasum took place at 33 days of fetal life, with the appearance of abomasal villi at 53 days. By 64 fetal days, the epithelium had changed from pseudostratified to simple mucous cylindrical. Acidic glycoproteins appeared at 46 fetal days. Neutral glycoproteins did not appear until later stages of development, near birth. We believe that the configuration of a simple epithelium with acidic secretion is enhanced at birth by the secretion of neutral glycoproteins which act as a buffer against acidic substances, and particularly against the abomasal acidity during lactation. Growth curves and formulae were set out for each tissue layer.

[Radiological study of the sternum of the growing sheep]. / Estudio radiológico del esternón del ovino en crecimiento.

A radiological investigation of the sternum of the sheep demonstrated distinct growth phases. Forty Merino sheep of mixed breeds were distributed into 4 age groups of 0, 45, 105 and 270 days. Each animal was radiographed in sternal and lateral recumbency. Measurements were made from the radiographs. The sternebrae are rectangular in newborn and become concave in adult. The curvature of the sternum is 16 to 17 degrees at day 0 and 27-28 degrees at day 270. The nucleus of ossification was seen in all sternebrae at 45 days of age, they were present only in the most caudal sternebrae at 105 days.

Histomorphometric analysis of the rumen of sheep during development.

Histomorphometric and scanning electron microscopic analyses were carried out on 74 embryos and fetuses and 20 sheep (early postnatal to adult age). Histodifferentiation of the rumen took place at 33 days of fetal life. Ruminal pillars were observed at 42 days, and at 61 days, ruminal papillae appeared as evaginations of the epithelial stratum basale. Neutral mucopolysaccharides first appeared in epithelial cells at 46 days of fetal life; thereafter, numbers decreased gradually and subsequently stabilized in postnatal life. Acid mucopolysaccharides, mucins, and mucoid compounds were not detected. Age and diet were recognized as factors that determine the structure of the ruminal mucosa. Growth curves and formulas were set out for each tissue layer.

Structural study of spongiosa tissue in growing sheep.

A study was made of 160 long bones taken from 40 native Merino sheep of both sexes. These animals, which represented uniform growth (mean growth-curve values), were divided into four groups which were slaughtered consecutively at 0, 45, 105 and 270 days old (0, 6.4, 15 and 38.5 weeks, respectively). The following bones were studied; humerus, femur, tibia and os coxae. Thin lamellae taken from the metaphyses of the bones obtained were fixed, decalcified and stained with hematoxylin-eosin to assess the development of the various components of growing bony tissue. The bones studied followed the same maturation pattern; the os coxae proved to be the best histological indicator in differentiating the age of the animals studied.

[Radiological and statistical determination of the morphological type of the canine skull: dolichocephaly, mesocephaly and brachycephaly]. / Détermination radiologique et statistique des types morphologiques crâniens chez le Chien: dolichocéphalie, mésocéphalie et brachycéphalie.

Cranio-encephalic morphology of three breeds of dogs (Greyhound, Pointer and Pekinese at the rate of 10 subjects, 5 males and 5 females, in each one) has been radiologically observed. Radiographic negatives in dorso-ventral and latero-lateral positions were taken and analyzed before and after the visualisation of the encephalic cavity using barium sulfate. 18 cranio-encephalic measurements were chosen and interpreted statistically. The results showed that certain variables were more closely correlated with morphologic types of the cranium than others. We discuss the validity of the data applied for clinical diagnostic or osteo-archeology determinations.

[The development of the bovine stomach: morphologic and morphometric analysis. II. Observations of the morphogenesis associated with the omasum and abomasum]. / El desarrollo del estómago del vacuno: análisis desde el prisma morfológico y morfométrico. Parte II: Observaciones morfogénicas asociadas al bloque omaso-abomásico.

This study represents a continuation of part 1 of a study of the development of the bovine stomach. Material and methods are more fully described in part i of the study. In this part 2 of the study further developmental stages and morphometric analysis is presented.

[The development of the bovine stomach: morphologic and morphometric analysis. III. Spatial and morphometric reconstruction]. / El desarrollo del estómago del vacuno: análisis desde el prisma morfológico y morfométrico. Parte III: Reconstrucción espacial y morfometría.

This work represents a summary of the study presented in parts I and II, previously published in this journal. The data collected in those studies is presented in three dimensional reconstructions of the stomach of the developing calf.

Utilization of computerized tomography for the determination of the volume of the cranial cavity of the galgo hound.

The volumetry of the cranial cavity of 30 galgo hounds (15 males and 15 females) has been studied by computerized axial scanning tomography and biostatistical methods. The serial tomodensitometric sections of heads were 5 mm thick and 5 mm distant, taken in sagittal and transverse planes. Results demonstrate a sexual differentiation, with a security of 99.99%. The discussion turns to zootechnical and osteoarcheological applications.

Computerized tomographic determination of the cranial volume of the dog applied to racial and sexual differentiation.

The volume of the cranial cavity of 70 dogs (35 males and 35 females) has been determined in two breeds, the galgo greyhound and the pointer, by radiological techniques (computerized tomography; CT) and biostatistical methods. Each head was submitted to a complete series of transverse tomographic sections taken perpendicularly to the basilar plane, every 5 mm and with a thickness of 5 mm. There is a clear difference between the breeds and the two sexes, with a minimal confidence of 99.95%. The application of the method to fit zootechnical and/or osteoarcheological needs is emphasized.

Histogenetic evolution of bovine gastric compartments during the prenatal period.

In order to carry out this study, 62 embryos and fetuses of Friesian cows were used, and every stomach was dissected and subjected to the usual laboratory procedures. After obtaining each preparation all the histological and metrical changes that took place in the wall of the viscus during its development are described. The compartments are histologically differentiated into three stages: in the first one there is no compartment differentiation: in the second one, the rumino-reticulum, omasum and abomasum have differentiated; and in the third one every compartment is differentiated. In group 16, (78 days of gestation), a decrease in thickness of the muscular layer of all compartments, parallel to the histological differentiation has been observed.