Assessment of markers of bone formation under controlled environmental factors and their correlation with serum minerals in adult sheep as a model for orthopaedic research

Abstract

SummaryEighteen healthy skeletally mature (3 years old) ewes, with an average weight of 45 kg, of the Portuguese Churra da Terra Quente breed were used to evaluate the normal values of total and bone-specific isoform of alkaline phosphatase serum activities (ALP and BALP, respectively) and serum osteocalcin (OC) and their correlation with the serum mineralscalcium (Ca), phosphorus (P), magnesium (Mg) and ionized calcium (Ca 2þ ). The sheep were maintained under controlled environmental conditions (constant diurnal photoperiod cycle and identical husbandry and feeding) for six weeks before the collection of the blood samples. The measurement of the total ALP and serum minerals was performed with automated biochemistry analysers using the BioMé rieux w kits, the serum electrolyte Ca 2þ Diametrics Medical, Inc w specific cassettes and the BALP and OC METRATM kits from QUIDEL Keywords Total and bone-specific alkaline phosphatase; osteocalcin; minerals; serum; sheepThe biochemical markers of bone metabolism reflect the bone turnover process and are usually divided into formation and resorption markers. Formation markers are proteins or enzymes secreted by osteoblasts during the bone formation process, such as serum total and bone-specific isoform of alkaline phosphatase (BALP), serum osteocalcin (OC) and serum procollagen type I C-and N-terminal propeptides. The latter two molecules are released during the type I collagen molecule formation. Bone resorption markers are those resulting from the breakdown of type I collagen

Serum total and bone alkaline phosphatase levels and their correlation with serum minerals over the lifespan of sheep

“…In this study, the values of serum Ca were always slightly below the reference range in all groups, as reported previously by Seebeck et al (2005) and Dias et al (2008). The serum P and Mg values of all groups were within the normal general reference range published for sheep (Kaneko et al, 1997).…”

“…Concerning serum BALP concentration, the values obtained in this study are similar to those found by Liesegang et al (2003), who reported a BALP reference value of 35-40 U/L in growing (6 months old) female sheep, those reported by Klein et al (2004) and Seebeck et al (2005) in skeletally mature female sheep (2 years old), in which the bone healing process was assessed, indicating a BALP reference range of 2.4-33.2 μg/L and 6.4-42.9 μg/L (17-112 U/L), respectively, those reported by Arens et al (2007) who indicated a serum BALP activity of 25-30 U/L in healthy female sheep (2 to 3 years old) during spring, those found by Dias et al (2008) who reported 15.0 ± 5.44 U/L serum BALP activity in healthy adult sheep (3 years old) under a controlled diurnal photoperiod cycle, and those described by Chavassieux et al (1997) who indicated a BALP value of 2-4 μg/L in mature (8 to 10 years old) ewes used in a preclinical study for osteopenia. The pattern of variation of serum BALP along the sheep lifetime (growing, mature, old, lactating, dry, pregnant) was similar to that described for total ALP, presenting a continuous decline of its serum levels along the sheep lifespan, namely in mature and older sheep (3 to 5 years old or older), probably indicating decreased bone turnover associated with ageing and metabolism.…”

Bone turnover markers in sheep and goat: A review of the scientific literature

“…Blood collection for measuring BTMs must be done at a specific time (morning) to avoid the influence of circadian variations (Klein et al 2004, Seebeck et al 2005, Dias et al 2008, Sousa et al 2014a. Blood samples can be collected from the cephalic vein (Klein et al 2004) or jugular vein (Dias et al 2008, Sousa et al 2014a into serological tubes containing no anticoagulant (Vernon et al 2010), and centrifuged (3000 rpm for 10 min) within 30 min of collection (Liesegang et al 2007).…”

Integrated Biomimemic Carbon Nanotube Composites for Biomedical Applications

“…Animal Model: Following the experimental protocol approved by the National Ethics Committee for Laboratory Animals (Portugal) (Dias et al, 2008), two healthy, adult male sheep with average weight of 45 kg, were used for the in-vivo implantation. The sheep were permanently housed indoors in group housing and were kept under a constant photoperiod cycle (light: from 07:00 to 19:00 hours; dark: from 07:00 to 19:00 hours), temperature (20 ± 2 o C) and humidity (50 ± 10%).…”

“…These components were mixed together just before the in vivo procedure; the resultant mixture was used as a viscous paste. This biocomposite was implanted into a sheep model system, in a similar manner to previous protocols (Dias et al, 2008;Henriksen et al, 2009). For the implantation, three holes were drilled in each tibia ( Figure 13a) and then the holes were filled with the bioactive bone cement paste (Figure 13b).…”