Alendronate disturbs femoral growth due to changes during immunolocalization of transforming growth factor-ß1 and bone morphogenetic protein-2 in epiphyseal plate.

BACKGROUND: The epiphyseal growth plate is an important anatomical segment localized on the ends of a long bone. Despite the abovementioned atractive reasons for alendronate's use, few data on the effect of alendronate during epiphyseal growth exist. AIM: Verify the effect of alendronate on the growth epiphyseal plate, and compare its effect with the size of the femur during the double-staining of the immunolocalization of transforming growth factor-ß1 (TGF-ß1) and bone morphogenetic protein-2 (BMP2) in endochondral ossifing in specimens that have received alendronate. METHODS: Forty newborn rats were randomly divided into two groups: a control group (were given applications of 1 mg/kg physiologic saline) and a group that received Alendronate (a dose of 2.5 mg/kg). These groups were then divided into two subgroups for euthanasia in two and 12 d of life. After euthanasia, the femurs were removed, and the femoral bones were measured linearly between the apex of the greater trochanter until the lower intercondylar midlle face to verify the probable bone growth between 3 and 12 d in control and alednroanto treated rats. Posteriorly, the surgical pieces were also sent to the histopathology laboratory to produce histological slides. The obtained slides were stained with hematoxylin and eosin to measure each of the cartilage zones in endochondral development. and other slides were immunohistochemically tested for anti- TGF-ß1 and BMP-2 antibodies to investigate the immunolocalization of these proteins in the epiphyseal plaque area. RESULTS: On the third day, some diferences between the control group and specimens treated with alendronate were verified. Macroscopiccaly, we found similarities in size between the femoral bones when we compared the control group with the specimens that received alendronate. On the 12th day, the bone size of the mice receiving the drug was significantly smaller than those of the control group. These results coincide with changes in the TGF-ß1 and BMP-2 expression. In the specimens that received alendronate, the TGF-ß1 was expressed in some sites of trabecular bone that was neoformed, peripherally to the bone marrow area. The BMP-2 was also positive in proliferative chondrocytes and hypertrofic chondrocytes. On the 12th day, all layers of chondrocytes exhibited positivity for BMP-2 in the specimens that received alendronate. In the interface between the trabecular bone and cartilage, an area of disorganized bone deposition was evident. Neoformed bone also appeared to be different at 12 d. In the control group, BMP-2 was positive in an intense area of bone trabeculae, whereas the alendronate-treated group showed TGF-ß1 positive trabeculae and a greater bone area. CONCLUSION: Alendronate alters the immunolocalization of TGF-ß1 and BMP-2 simultaneously, a condition that changes the usual histological aspects of the cartilage zone and impairs epiphysis growth and femur growth.

Extensive burn injury causes bone collagen network alteration and growth delay related to RANK-L immunoexpression change.

PURPOSE: Extensive burn injury mainly affects children, and hypermetabolic state can lead to growth delay. This study aimed to investigate bone histopathological and morphometric aspects, collagen fibers network and the immunoexpression of biological markers related to bone development in a young experimental model for extensive burn. MATERIALS AND METHODS: A total of 28 male Wistar rats were distributed into Control (C) and subjected to scald burn injury (SBI) groups. Sham or injured animals were euthanized 4 or 14 days post-lesion and proximal epiphyses of the femur were submitted to histological, morphometric (thickness epiphyseal plate), and RUNX-2 and receptor activator of nuclear factor kappa- ß ligand (RANK-L) immunoexpression methods. RESULTS: Histopathological femoral findings showed delayed appearance of the secondary ossification center in SBI, 14 days post-injury. Collagen fibers 4 days after injury were observed in articular cartilage as a pantographic network with a transversally oriented lozenge-shaped mesh, but this network was thinner in SBI. Fourteen days after the injury, the pantographic network of collagen presented square-shaped mesh in C, but this aspect was changed to a wider mesh in SBI. Morphometric analysis of epiphyseal plate revealed that the SBI group had less thickness than the respective controls (p<0.05). RUNX-2 showed no difference between groups, but RANK-L score was higher in all SBI groups. CONCLUSIONS: Extensive burn injury causes delayed bone growth and morphological changes. Alterations in collagen network and enhancement in immunoreactivity of RANK-L result in increased osteoclastogenesis.

The epiphyseal plate closure phenomena for male and female Japanese quail ( Coturnix coturnix japonica ): histological and biochemical alterations

This study was conducted to determine the effect of sex on ossification processes in quail by determining the exact closure timing of the epiphyseal plate in the proximal region of the femur. This was done by investigating the histological and biochemical parameters affecting the osteogenesis process that takes place following quail hatching to observe if any variation existed between males and females in this regard. For this purpose, blood samples were collected from six male and female specimens via IV catheters every week for the first 42 days that followed hatching. The samples were transferred into serum tubes, and PTH (PTH), triiodothyronine (T3), thyroxine (T4), inorganic phosphorus, calcium, and vitamin D values in the samples, which are known to have an impact on ossification, were analyzed. The specimens from which the blood samples were collected were then euthanized, and histological cut-sections that covered the epiphyseal growth plate were collected, along with the bone sections of the proximal regions of the right femur. Considering decalcification, these histological sections were kept in an ethylene diamine tetra acetic acid (EDTA) solution. Routine histological examinations were then conducted on these sections, after which they were embedded in paraffin. Crossman's modified triple staining method was used to prepare them, and Wilcoxon Signed Ranks Test was used to statistically evaluate whether the inspected biochemical parameters played a role in the ossification process of quail and whether a statistical difference existed between sexes in this regard. The findings of our study revealed that poultry animals also have five zones in the epiphyseal plate as do mammals, and they have calcified cartilage areas. The findings also indicate that, while ossification starts to occur both in male and female quail specimens, calcification occurs more frequently in females. It was determined that the proximal epiphyseal plate regions of the femur close at the end of the sixth week in both sexes of quail, although the calcification and ossification are more advanced in some females compared with males.(AU)

How does protein malnutrition or food deprivation interfere with the growth of the epiphyseal plate in animals? / Cómo interfieren la desnutrición protéica o la privación alimentaria en el crecimiento de la placa epifisaria de animales?

The aim of this study was to conduct a literature review of impacts of protein malnutrition and/or early food deprivation on the formation of the growth plate in young animals. A search was performed using the databases PubMed/MEDLINE, LILACS, SciELO and the Cochrane Library, without language restrictions or any limit as to year. Initially, 150 articles were identified, however, after application of the inclusion and exclusion criteria only five remained. In three studies the nutritional stress was due to protein malnutrition, another due to fasting and the fifth was due to food restriction. All the studies had some methodological omissions. The studies included in this review-demonstrated corroboration in the results obtained, regardless of whether the animals had been subjected to protein malnutrition, fasting or food restriction. The findings uncovered were reduction in height of the epiphyseal plate, in the number of proliferative and hypertrophic chondrocytes, in the bone growth rate and in the longitudinal length of the bone in animals subjected to nutritional stress. In this systematic review, it was possible to observe the susceptibility of the epiphyseal plate in the first place, and secondarily, of the long bones to the effects of nutritional stress by means of protein malnutrition or food deprivation applied in young animals.

El objetivo fue realizar una revisión de la literatura sobre el impacto de la desnutrición proteica y/o privación de alimentos en la temprana formación de la placa de crecimiento en animales jóvenes. La búsqueda fue realizada en las bases de datos PubMed/MEDLINE, LILACS, SciELO y Biblioteca Cochrane sin restricción de lengua o límite de año. Fueron identificados inicialmente ciento cincuenta artículos que, posterior a la aplicación de los criterios de inclusión y exclusión, solo quedaron cinco. En tres estudios el estrés nutricional fue causado por la desnutrición proteica, otro al ayuno y el tercero fue por restricción alimentaria. Todos los estudios presentaban algunas omisiones metodológicas. Las investigaciones incluidas en esta revisión demostraron concordancia en sus resultados obtenidos, independientemente que los animales hayan sido sometidos a desnutrición proteica, ayuno o restricción alimentaria. Los datos obtenidos mostraron que los animales sometidos al estrés nutricional presentaron una reducción en la altura de la placa epifisaria, en el número de condrocitos proliferativos e hipertróficos, en la tasa de crecimiento óseo y en la longitud ósea. En esta revisión sistemática fue posible observar que los efectos del estrés nutricional, a través, de desnutrición proteica o de la privación alimentaria aplicada en animales jóvenes presentan, en primer lugar, una susceptibilidad de la placa epifisaria y de los huesos largos de manera secundaria.