Different doses of strontium ranelate and mechanical vibration modulate distinct responses in the articular cartilage of ovariectomized rats.

OBJECTIVE: To investigate the effects of different strontium ranelate (SrR) doses alone or in combination with low-intensity and high-frequency mechanical vibration (MV) on articular cartilage in ovariectomized rats. DESIGN: Fifty 6-month-old female Wistar rats underwent ovariectomy (OVX) and after 3 months were divided into: control group (Control); SrR 300 mg/kg/day (SrR300); SrR 625 mg/kg/day (SrR625); MV; SrR 625 mg/kg/day plus MV (SrR625 + MV). The vehicle and the SrR were administered by gavage 7 days/week and vibration (0.6 g/60 Hz) was performed for 20 min/day, 5 days/week. Bone mineral density (BMD) and body composition were evaluated by densitometry. Changes in cartilage were assessed 90 days after treatment by histomorphometry; immunohistochemistry analysis evaluating cell death (caspase-3), tumor necrosis factor-α (TNF-α), metalloproteinase 9 (MMP-9) and type II collagen; Osteoarthritis Research Society International (OARSI) grading system and glycosaminoglycans (GAGs) analyses. RESULTS: SrR-treated groups exhibited a lower OARSI grade, a smaller number of chondrocyte clusters, increased levels of chondroitin sulfate (CS) and decreased expression of caspase-3. Additionally, compared to all the groups, SrR300 exhibited increased levels of hyaluronic acid (HA). Vibration applied alone or in combination accelerated cartilage degradation, as demonstrated by increased OARSI grade, reduced number of chondrocytes, increased number of clusters, elevated expression of type II collagen and cell death, and was accompanied by decreased amounts of CS and HA; however, MV alone was able to reduce MMP-9. CONCLUSIONS: SrR and vibration modulate distinct responses in cartilage. Combined treatment accelerates degeneration. In contrast, SrR treatment at 300 mg/kg/day attenuates osteoarthritis (OA) progression, improving cartilage matrix quality and preserving cell viability in ovariectomized rats.

Osteocytic connexin 43 is not required for the increase in bone mass induced by intermittent PTH administration in male mice.

OBJECTIVE: To investigate whether osteocytic connexin 43 (Cx43) is required for the bone response to intermittent PTH administration, and whether the connexin is involved in maintaining the bone matrix. METHODS: Human PTH(1-34) was injected to adult male mice expressing (Cx43(fl/fl)) or not osteocytic Cx43 (Cx43(fl/fl);DMP1-8kb-Cre) daily (100 µg/kg/d) for 14 days. RESULTS: Cx43(fl/fl);DMP1-8kb-Cre mice have no difference in body weight and BMD from 1 to 4 months of age. Intermittent PTH administration increased BMD and BV/TV and induced a similar increase in type I collagen, alkaline phosphatase, runx2, osteocalcin, and bone sialoprotein expression in mice from both genotypes. On the other hand, osteocytic deletion of Cx43 did not alter mRNA levels of glycosaminoglycans, proteoglycans, collagens and osteoblast-related genes. In addition, expression of collagens assessed by immunohistochemistry was not affected by deleting osteocytic Cx43. However, PTH administration increased type II collagen only in Cx43(fl/fl) control mice, whereas hormone increased type I collagen expression only in Cx43(fl/fl);DMP1-8kb-Cre mice. Furthermore, PTH increased maturity of collagen fibers in control, but not in Cx43-deficient mice. CONCLUSION: Expression of Cx43 in osteocytes is dispensable for bone anabolism induced by intermittent PTH administration; but it can modulate, at least in part, the effect of PTH on the bone matrix environment.

Effects of different doses of soy isoflavones on bone tissue of ovariectomized rats.

AIM: Studies report that hormone replacement prevents osteoporosis, but there are doubts whether isoflavones are really efficient in this process. The aim of this study was to evaluate the effects of different doses of soy isoflavones on bone tissue of ovariectomized rats. METHODS: Forty female rats at the age of 6 months were ovariectomized and, after 3 months, the animals were divided into four groups: GI - Control (treated with drug vehicle); GII - treated with isoflavones (80 mg/kg per day); GIII - treated with isoflavones (200 mg/kg per day) and GIV - treated with isoflavones (350 mg/kg per day). Soy isoflavones were administered by gavage for 90 consecutive days. After treatment, the rats were euthanized and their distal femurs were removed for histological routine, histochemistry and biochemical study. Histological sections were stained with hematoxylin-eosin or subjected to picrosirius red and alcian blue methods. Shafts of femurs were submitted to biochemical assay and tibias were subjected to biophysical and biomechanical tests. RESULTS: In distal femurs, the trabecular bone volume was higher in the groups treated with isoflavones, being higher in GIV, while the cortical bone width and the presence of mature type I collagen fibers were higher in GII. At the trabecular bone region, the percentage of total glycosaminoglycans (GAGs) was higher in GII and the percentage of only sulfated GAGs was higher in GIII, while the higher content of chondroitin sulfate in shafts of femurs was seen in GIV. Biophysical and biomechanical tests in tibias did not differ among the groups. CONCLUSION: Our data indicate that soy isoflavones improve bone quality in femurs of rats by increasing histomorphometric parameters, the content of GAGs and mature type I collagen fibers. These positive effects are dose-dependent and it was different in cortical and trabecular bone.

Gradual strenuous running regimen predisposes to osteoarthritis due to cartilage cell death and altered levels of glycosaminoglycans.

OBJECTIVE: To investigate the hypothesis that strenuous running is a predisposing factor for osteoarthritis. DESIGN: Wistar rats were divided into two groups: a control group (CG) and a trained group (TG). The TG underwent a strenuous treadmill running training regimen of controlled intensity, exhibiting progressively improvement of fitness over 12 weeks, running at least 55 km during this period and finally performing an ultra-endurance running exercise to exhaustion. After this period, rats from both groups were euthanized and their knees removed. The articular cartilage was dissected and submitted to histomorphometrical, histomorphological, and immunohistochemical analyses evaluating cell death pathway (caspase-3 and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL)) and inflammatory cytokines [interleukin-1α (IL-1α) and tumor necrosis factor-α (TNF-α)]. In addition, the tissues were analyzed regarding the types and the content of glycosaminoglycans. RESULTS: The TG knee joints exhibited increase in the number of chondrocytes and chondrocyte clusters, as well as significantly increased levels of caspase-3, a protein involved in apoptosis, and of inflammatory cytokines IL-1α and TNF-α. In addition, histologically higher grades of osteoarthritis (Osteoarthritis Research Society International - OARSI grading), and significantly decreased levels of chondroitin sulfate and hyaluronic acid. Knee cartilage thickness and TUNEL did not significantly differ between the two groups. CONCLUSIONS: The articular cartilage of rats subjected to a strenuous running regimen of controlled intensity exhibited molecular and histological characteristics that are present in osteoarthritis.

Effects of soy isoflavones and mechanical vibration on rat bone tissue.

OBJECTIVE: To investigate the effects of soy isoflavones (Iso) and mechanical vibration treatments alone or combined on bone extracellular matrix constituents of ovariectomized rats. METHODS: Forty female Wistar rats at the age of 6 months were ovariectomized (Ovx) and ten were sham-operated (sham). After 3 months, the animals were divided into five groups: GI (sham); GII (Ovx); GIII, ovariectomized and orally treated with isoflavones (200 mg/kg) for 90 consecutive days; GIV, ovariectomized and submitted to vibration for 90 days (5 days/week); GV, ovariectomized and treated with isoflavones plus vibration. After treatments, the rats were euthanized, and their femurs were removed for histological routine and biochemical study. Histological sections were stained with hematoxylin-eosin, picrosirius red and alcian blue. Shaft of femurs were submitted to biochemical assay and tibias were subjected to biophysical and biomechanical tests. RESULTS: Treatments did not have significant effects on the trabecular bone volume, but the combined treatments showed trophic effects on the cortical bone width and area. Bone density and the content of organic material of the tibias were higher in the GIV and GV groups. The GV group showed the highest presence of mature collagen fibers and content of total glycosaminoglycans, while the highest contents of chondroitin sulfate and other sulfated glycosaminoglycans were seen in the GIV group. CONCLUSION: The mechanical vibration treatment is more efficient than soy isoflavones in improving bone quality by increasing the bone density, the content of sulfated glycosaminoglycans and the presence of mature collagen fibers. In addition, the combined interventions have partial trophic and synergistic effects that are bone site-specific in ovariectomized rats.

Exocrine Glands of Schwarziana quadripunctata (Hymenoptera, Apinae, Meliponini).

This article 'describes the location, anatomy, histology and ontogeny of adult Schwarziana quadripunctata exocrine glands. These glands appear either as individualized organs (salivary gland system and Dufour gland) or as epidermis differentiation (tegumentary glands). Variations in the occurrence and degree of development among colony components with regard to their degree of maturity are also described.

Ovarian growth during larval development of queen and worker of Apis mellifera (Hymenoptera: Apidae): a morphometric and histological study.

The present work reports the differences between the ovarian grow in queen and worker larvae of A. mellifera, from the start of differential feeding. The observations made of the growth rates in larvae of both castes showed that the queen and worker larvae have the same rates of cephalic capsule growth from one instar to another but the weight gain is greater in queens. In the same way, the draw areas of ovaries of queens increase more and continuously, while from the 5th instar on the ovaries of workers decrease in size. The decrease is due to a loss of ovariole numbers that starts early in the worker larvae and increases in the 4th-5th instar. The ovarian shape in queens and workers became different in the last larval instars.

Ovarian growth during larval development of queen and worker of Apis mellifera (Hymenoptera: Apidae): a morphometric and histological study

The present work reports the differences between the ovarian grow in queen and worker larvae of A. mellifera, from the start of differential feeding. The observations made of the growth rates in larvae of both castes showed that the queen and worker larvae have the same rates of cephalic capsule growth from one instar to another but the weight gain is greater in queens. In the same way, the draw areas of ovaries of queens increase more and continuously, while from the 5th instar on the ovaries of workers decrease in size. The decrease is due to a loss of ovariole numbers that starts early in the worker larvae and increases in the 4th-5th instar. The ovarian shape in queens and workers became different in the last larval instars

Exocrine glands of Schwarziana quadripunctata (Hymenoptera, Apinae, Meliponini)

This article describes the location, anatomy, histology and ontogeny of adult Schwarziana quadripunctata exocrine glands. These glands appear either as individualized organs (salivary gland system and Dufour gland) or as epidermis differentiation (tegumentary glands). Variations in the occurrence and degree of development among colony components with regard to their degree of maturity are also described

Cell nucleus activity during post-embryonic development of Apis mellifera L. (Hymenoptera: Apidae). Intranuclear acid phosphatase

We report nuclear acid phosphatase activity in the somatic (intra-ovariolar and stromatic) and germ cells of differentiating honey bee worker ovaries, as well as in the midgut cells of metamorphosing bees. There was heterogeneity in the intensity and distribution of electron dense deposits of lead phosphate, indicative of acid phosphatase activity in the nuclei of these tissues, during different phases of post-embryonic bee development. This heterogeneity was interpreted as a variation of the nuclear functional state, related to the cell functions in these tissues