Ovariectomy<i>vs</i>. Hypofunction: Their Effects on Rat Mandibular Bone

Rawlinson, Simon C.F.; Boyde, A.; Davis, Graham; Howell, Peter; Hughes, Francis J.; Kingsmill, V.J.

doi:10.1177/0022034509340132

Cited by 33 publications

(23 citation statements)

References 25 publications

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“…According to Rawlinson and colleagues [27], osteoporosis in the jaw and calvaria bones only occurs approximately 150 days after the bilateral excision of ovaries in female rats receiving normal feed.…”

Section: Discussionmentioning

confidence: 99%

Low-level laser therapy improves bone formation: stereology findings for osteoporosis in rat model

et al. 2015

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Low-level laser therapy (LLLT) benefits bone metabolism, but its use needs to be standardized. We evaluated the effects of LLLT on bone defects in calvaria of ovariectomized rats. Stereology was used to calculate tissue repair volume (V tr ), density of trabecular bone volume (Vv t ), total volume of newly formed trabecular bone (Vtot), and the area occupied by collagen fibers (A C ). Fifty-four Wistar rats were submitted to bilateral ovariectomy, and bone defects were created in calvaria after 150 days. The animals were divided into nine groups (n = 6), and 24 h after defects, the treatment started with a 780-nm low-intensity GaAlAs laser: G1, G2, and G3 received 3 sessions of 0, 20, and 30 J/cm(2) respectively; G4, G5, and G6 received 6 sessions of 0, 20, and 30 J/cm(2), respectively; and G7, G8, and G9 received 12 sessions of 0, 20, and 30 J/cm(2), respectively. A normal distribution was found for all of the data. The test used to verify the normality was the Kolmogorov-Smirnov (KS, p > 0.05). The one-way ANOVA followed by Tukey's post hoc test was used for data processing. A difference of p < 0.05 was considered statistically significant. Groups G2 and G1 showed significance for V tr , Vv t , Vtot, and (A C ). Results were significant for (Vv t ) and (Vtot) between G3 and G1. There were no significant results between G5 and G4 as well as between G8 and G7. Groups G6 and G4 results showed statistical difference for V tr , Vv t , Vtot, and (A C ). Groups G9 and G7 showed significance for V tr , Vv t , Vtot, and (A C ). In conclusion, there was new bone formation in the groups that received 20 and 30 J/cm(2) when compared to control groups, but over time, the dose of 30 J/cm(2) showed better stereological parameters when compared to 20 J/cm(2).

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Section: Discussionmentioning

confidence: 99%

Low-level laser therapy improves bone formation: stereology findings for osteoporosis in rat model

et al. 2015

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“…In addition, the significant suppression of marrow cell differentiation of the ER group was similar to the slow growing chicks. Although these findings may be counter intuitive to the increases in bone volume in the vertebral trabecular bone of the ER animals, the increased mineral apposition rate found in slower growing chicks offers an explanation for the increased bone volume with lower osteoblast differentiation [68,71]. …”

Section: Discussionmentioning

confidence: 99%

Different effects on bone strength and cell differentiation in pre pubertal caloric restriction versus hypothalamic suppression

Joshi

Safadi

Barbe

et al. 2011

Bone

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Hypothalamic amenorrhea and energy restriction during puberty affect peak bone mass accrual. One hypothesis suggests energy restriction alters hypothalamic function resulting in suppressed estradiol levels leading to bone loss. However, both positive and negative results have been reported regarding energy restriction and bone strength. Therefore, the purpose of this study was to investigate energy restriction and hypothalamic suppression during pubertal onset on bone mechanical strength and the osteogenic capacity of bone marrow-derived cells in two models: female rats treated with gonadotropin releasing hormone antagonists (GnRH-a) or 30% energy restriction. At 23 days of age, female Sprague Dawley rats were assigned to three groups: control group (C, n=10), GnRH-a group (n=10), and Energy Restriction (ER, n=12) group. GnRH-a animals received daily injections for 27 days. The animals in the ER group received 70% of the control animals’ intake. After sacrifice (50 days of age), body weight, uterine and muscle weights were measured. Bone marrow-derived stromal cells were cultured and assayed for proliferation and differentiation into osteoblasts. Outcome measures included bone strength, bone histomorphometry and architecture, serum IGF-1 and osteocalcin. GnRH-a suppressed uterine weight, decreased osteoblast proliferation, bone strength, trabecular bone volume and architecture compared to control. Elevated serum IGF-1 and osteocalcin levels and body weight were found. The ER model had an increase in osteoblast proliferation compared to the GnRH-a group, similar bone strength relative to body weight and increased trabecular bone volume in the lumbar spine compared to control. The ER animals were smaller but had developed bone strength sufficient for their size. In contrast, suppressed estradiol via hypothalamic suppression resulted in bone strength deficits and trabecular bone volume loss. In summary, our results support the hypothesis that during periods of nutritional stress the increased vertebral bone volume may be an adaptive mechanism to store mineral which differs from suppressed estradiol resulting from hypothalamic suppression.

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“…Osteocyte survival and, hence, number has been shown to be related to daily strain stimuli (Noble et al, 2003). In rats, the number of osteocyte nuclei per mm 2 do not differ that much between mandibular and ulnar bone (Rawlinson et al, 2009). Should this also be true for the rabbit, it would be in accordance with the similarity in the observed strain stimuli.…”

Section: On the Similarities Between Habitual Long-bone And Mandibulamentioning

confidence: 78%

Variations in habitual bone strains in vivo: Long bone versus mandible

Jong

Korfage

Langenbach

2010

Journal of Structural Biology

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Ovariectomyvs. Hypofunction: Their Effects on Rat Mandibular Bone

Cited by 33 publications

References 25 publications

Low-level laser therapy improves bone formation: stereology findings for osteoporosis in rat model

Low-level laser therapy improves bone formation: stereology findings for osteoporosis in rat model

Different effects on bone strength and cell differentiation in pre pubertal caloric restriction versus hypothalamic suppression

Variations in habitual bone strains in vivo: Long bone versus mandible

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