Temporal Analysis of Rat Growth Plates: Cessation of Growth with Age Despite Presence of a Physis

Roach, Helmtrud I.; Mehta, Gautam; Oreffo, Richard O.C.; Clarke, Nicholas; Cooper, Cyrus

doi:10.1177/002215540305100312

Cited by 159 publications

(151 citation statements)

References 46 publications

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“…In some species, the epiphysis may remain ''open'' for some time beyond the achievement of sexual maturity (Kilborn et al, 2002). As previously demonstrated in rats by both Trudel et al (2001) and Roach et al (2003) and others, we observed histologically 'open' physes in rats at 1 year of age. In departure from the former and in agreement with the latter study, we measured no significant proliferative activity or daily growth accumulation by the proximal tibial growth plate by our pulse labeling studies at this late time point.…”

Section: Conclusion and Discussionsupporting

confidence: 85%

Ontogeny of Skeletal Maturation in the Juvenile Rat

Horton

Bariteau

Loomis

et al. 2008

The Anatomical Record

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Systemic regulation of the cellular processes that produce endochondral elongation and endochondral mineralization during postnatal skeletal maturation are not completely understood. In particular, a mechanism coupling the decline of cellular activity in the bone microenvironment to the onset of sexual maturity remains elusive. The purpose of this study was to empirically integrate the dynamic progression of bone mineral accrual and endochondral elongation as a function of animal age in growing male and female Sprague-Dawley rats. We used serial dual-energy X-ray absorptiometry (DXA) and radiography to study the temporal progression of bone growth and mineral accrual from weaning to adulthood. We observed that skeletal maturation proceeds in a pattern adequately described by the Gompertz function. During this period of growth, we found that serum markers of osteoblastic bone formation declined with age, while osteoclastic bone resorption activity remained unchanged. We also report a slight lag in the age at inflection in the rate of bone mineral accrual relative to the rate of tibial elongation and that both endochondral processes eventually come to asymptotic equilibrium by approximately 20 weeks of age. In addition, we studied tibial growth plate histomorphometry at select time points through 1 year of age. We report that, despite the histologic persistence of physeal cartilage, very little proliferative or elongative activity was measured in this tissue beyond 20 weeks of age. Taken together, these data provide insight to the temporal coordination of postnatal endochondral growth processes.

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Section: Conclusion and Discussionsupporting

confidence: 85%

Ontogeny of Skeletal Maturation in the Juvenile Rat

Horton

Bariteau

Loomis

et al. 2008

The Anatomical Record

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“…Endochondral bone formation in mice differs from that in humans, as their growth plates do not fuse completely during sexual maturation (Roach et al 2003). Therefore, it can be argued that estrogen receptors in mice, unlike those in humans, do not mediate growth plate fusion (Lubahn et al 1993).…”

Section: Discussionmentioning

confidence: 99%

“…Unlike in humans, the growth plates in mice do not fuse completely during sexual maturation (Roach et al 2003). However, their height diminishes considerably after sexual maturation, and the protein synthesis rate in the chondrocytes decreases.…”

Section: Introductionmentioning

confidence: 86%

The aromatase inhibitor letrozole increases epiphyseal growth plate height and tibial length in peripubertal male mice

Eshet

Maor²,

Ari³

et al. 2004

Journal of Endocrinology

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Sex hormones may influence longitudinal growth, either indirectly, by affecting the growth-hormone-insulin-like growth factor I (IGF-I) axis, or directly, by affecting changes within the epiphyseal growth plate (EGP). The aim of the present study was to investigate the effects of letrozole, an aromatase inhibitor, on longitudinal growth and changes in the EGP in vivo. Eighteen peripubertal male mice were divided into three groups. The first group was killed at baseline, the second was injected with letrozole (Femara) s.c., 2 mg/kg body weight/day, for 10 days, and the third was injected with the vehicle alone. Serum testosterone levels were found to be significantly higher in the treated group than in the controls. Letrozole induced a significant increase in body weight, tail length and serum growth hormone level, but had no significant effect on the level of serum IGF-I. On histomorphometric study, there was a significant increase (12%) in EGP height in the treated animals compared with controls. Immunohistochemistry showed a 3·4-fold letrozole-induced increase in the proliferation of the EGP chondrocytes, as estimated by the number of proliferation cell nuclear antigen-stained cells, and a decrease in the differentiation of the EGP chondrocytes, as estimated by type X collagen staining. Letrozole did not interfere with type II collagen levels. The study group also showed a twofold increase in the number of IGF-I receptor-positive cells compared with controls. In conclusion, the aromatase inhibitor, letrozole, appears to increase the linear growth potential of the EGP in mice.

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“…In rats, the growth plate remains present in aged rats despite the absence of longitudinal growth 13 . For this reason the growth plate was radiographically visible at all moments in both groups from both craniocaudal and mediolateral views.…”

Section: Discussionmentioning

confidence: 99%

“…On the other hand, differences in the bone length on day 21 were observed especially in G1 as compared to G2, suggesting a negative effect of LLLT on growth plate proportional to the number of irradiation days. In addition, the rats were approximately 6 weeks of age on the first day of irradiation, a transitional period between a phase of accelerating growth (up to 5 weeks) and a time of decelerating growth (8-16 weeks) 13 , indicating that irradiation action occurs despite the longitudinal length rate of the bone.…”

Section: Discussionmentioning

confidence: 99%

Low-level laser on femoral growth plate in rats

Oliveira¹,

Rahal

Pereira

et al. 2012

Acta Cir. Bras.

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PURPOSE:To determine the influence of low-level laser therapy on femoral growth plate in rats. METHODS:Thirty male Wistar rats aged 40 days were divided into two groups, G1 and G2. In G1 the area of the distal growth plate of the right femur was irradiated at one point using GaAlAs laser 830 nm wavelength, output power of 40 mW, at an energy density of 10 J/cm 2 . The irradiation was performed daily for a maximum of 21 days. The same procedure was done in G2, but the probe was turned off. Five animals in each group were euthanized on days 7, 14 and 21 and submitted to histomorphometric analysis. RESULTS:In both groups the growth plate was radiographically visible at all moments from both craniocaudal and mediolateral views.On the 21st day percentage of femoral longitudinal length was higher in G2 than G1 compared to basal value while hypertrophic zone chondrocyte numbers were higher in G1 than G2. Calcified cartilage zone was greater in G1 than in G2 at all evaluation moments.Angiogenesis was higher in G1 than in G2 at 14th and 21st days. CONCLUSION:The low-level laser therapy negatively influenced the distal femoral growth plate.Key words: Lasers. Bone Development. Chondrocytes. Laser Therapy, Low-Level. Rats. RESUMO OBJETIVO:Determinar a influência do Laser Terapêutico de Baixa Potência sobre a placa de crescimento de ratos. MÉTODOS:Trinta ratos Wistar machos com 40 dias de idade foram divididos em dois grupos, G1 e G2. O grupo G1 foi submetido à irradiação com laser GaAlAs 830 nm, potência de saída de 40 mW, e densidade de energia de 10 J/cm2. A irradiação foi aplicada diariamente por um período máximo de 21 dias. O mesmo procedimento foi realizado no grupo G2, com a probe desativada. Cinco animais em cada grupo foram sacrificados nos dias 7, 14 e 21 e submetidas à análise histomorfométrica. RESULTADOS:Em ambos os grupos, o disco fisário esteve radiograficamente visível em todos os momentos nas incidências craniocaudal e médio-lateral. No 21º dia a porcentagem de comprimento longitudinal do fêmur foi maior em G1 que em G2 em relação ao valor basal, e o número de condrócitos da zona hipertrófica foi maior em G1 que em G2. A zona de cartilagem calcificada estava maior em G1 em relação a G2 em todos os momentos de avaliação. A angiogênese foi maior em G1 que em G2 nos 14º e 21º dias. CONCLUSÃO:A terapia com laser terapêutico de baixa potência influenciou negativamente o disco fisário distal do fêmur de ratos.Descritores: Lasers. Desenvolvimento Ósseo. Condrócitos. Terapia a Laser de Baixa Intensidade. Ratos.Oliveira SP et al.

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Temporal Analysis of Rat Growth Plates: Cessation of Growth with Age Despite Presence of a Physis

Cited by 159 publications

References 46 publications

Ontogeny of Skeletal Maturation in the Juvenile Rat

Ontogeny of Skeletal Maturation in the Juvenile Rat

The aromatase inhibitor letrozole increases epiphyseal growth plate height and tibial length in peripubertal male mice

Low-level laser on femoral growth plate in rats

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