Effect of ethane-1-hydroxy-1,1-bisphosphonate (EHBP) on endochondral ossification lesions induced by a lethal oral dose of uranyl nitrate

Abstract

A 350 mg/kg body weight (b.w.) oral dose of uranyl nitrate (UN) caused 100% mortality in mice three days after administration, due to resulting kidney lesions. Mortality decreased 50% after an oral (o) or subcutaneous (sc) dose of bisodic etidronate (EHBP). Given that bone is also a target organ for uranium (U) in acute intoxication, the aim of this work was to study the effect of exposure to a lethal oral dose of UN on endochondral ossification, and the latter's response to EHBP treatment. One hundred male Balb/c mice weighing 25 g were assigned to one of ten groups. Group I served as control. Group II received a lethal 350 mg/kg b.w. oral dose of UN by gavage. Groups III, IV, VII, and VIII received an equal dose of UN immediately followed by a single 500 mg/kg oral dose of EHBP in groups III and VII and a single 50 mg/kg subcutaneous dose of EHBP in groups IV and VIII. Groups V and IX only received a single 500 mg/kg oral dose of EHBP, and groups VI and X received a single 50 mg/kg subcutaneous dose of EHBP. The animals in groups II, III, IV, V, and VI were sacrificed 48 h after the onset of the experiment, whereas those in groups VII, VIII, IX, and X were killed at 14 days. Histologic and histomorphometric studies were performed on the femurs to determine growth cartilage width, bone volume, and metaphyseal bone activity. Our results showed that all growth cartilage and metaphyseal bone histomorphometric parameters were significantly lower in animals exposed to UN at 48 h than in controls. EHPB administration was found to prevent this condition at 48 h reaching similar values to those of controls. Although histomorphometric values did not reach control values at 14 days, they were higher than those of animals exposed to UN at 48 h not treated with EHBP. It is noteworthy that these values also decreased in animals only receiving EHBP at 14 days. Our results show that EHBP effectively ameliorates the adverse effects of a lethal dose of UN on endochondral ossification.

Intracellular Metabolism of Uranium and the Effects of Bisphosphonates on Its Toxicity

“…As for metaphyseal cartilage, a decrease in mandibular growth in uranium-exposed animals was observed. This finding is in agreement with the inhibition on bone formation and endochondral ossification (Díaz Sylvester et al, 2002;Bozal et al, 2005). The reduction in dental development is associated to cementum and dentin of the dental root.…”

“…Several compounds ranging from natural and simple such as sodium citrate, to more sophisticated synthetic chelators agents have been tested in order to treat uranium contamination. To date, several studies have been performed to determine the effectiveness of different chelating agents in preventing the toxic effets of uranium on the body (Domingo et al, 1990;Cabrini et al, 1984;Stradling et al, 1991;Martinez et al, 2000;Bozal et al, 2005). However, not all chelating compound tested showed to be effective to counterbalance the action of uranium.…”

“…EHBP reverses induceduranium alterations on the metaphyseal cartilage and endochondral ossification. Although EHBP causes a decrease in the height of the metaphyseal cartilage, it does not alter the activity or the formation of bone subchondral trabeculae indicating that though at a slower rate, the endochondral ossification process continues (figure 3) (Bozal et al, 2005). During growth, catch-up growth has been defined as growth with a velocity above the statistical limits of normality for age during a defined period of time, which follows a period of impaired growth (Williams et al, 1974).…”

Modes of action associated with uranium induced adverse effects in bone function and development

“…In Wistar rats, uranium exposure reduced bone growth, volume, and mineralization of the tibial metaphysis (Diaz Sylvester et al, 2002;Fukuda et al, 2006;Guglielmotti et al, 1984;Ubios et al, 1994) and decreased mandibular bone growth (Diaz Sylvester et al, 2002;Pujadas Bigi and Ubios, 2007;Ubios et al, 1994). Similar effects have been reported in the femoral metaphysis of Balb/c mice and the tibial metaphysis of Wistar rats, in which uranium exposure was associated with decreased growth cartilage, bone volume, bone formation surfaces and mineralization (Bozal et al, 2005;Fukuda et al, 2006;Guglielmotti et al, 1984) (see Supplementary Table S1). Cabrini et al (1984), Guglielmotti et al (1984Guglielmotti et al ( , 1985Guglielmotti et al ( , 1987, and Ubios et al (1991) observed that acute uranium exposure resulted in decreased osteoblast activity and intramembranous ossification in Wistar rats (Table 1) Guglielmotti et al, 1985Guglielmotti et al, , 1984Ubios et al, 1990).…”

“…Fukuda et al (2006) reported similar findings in Wistar rats where bone resorption measured in trabecular bone was significantly increased at 28 days post exposure to a single dose of uranium, and Bozal et al, 2005 observed that in Balb/c mice acute (48 h) exposure to uranium increased bone resorption in the metaphysis of the femoral bone (Bozal et al, 2005;Fukuda et al, 2006). Furthermore, an epidemiological study by Kurttio et al (2005) reported an association between uranium exposure via drinking Ubios et al, 1994;Diaz-Sylvester et al, 2002;Pujadas Bigi and Ubios, 2007 # Femoral bone volume in metaphysis # Femoral growth cartilage width # Femoral cell proliferation in growth cartilage Bozal et al, 2005 Intramembranous ossification # Alveolar bone formation and volume in healing sockets Guglielmotti et al, 1984Guglielmotti et al, , 1985Guglielmotti et al, 1987;Ubios et al, 1990 # Alveolar bone volume in healing sockets Cabrini et al, 1984 Bone modeling and remodeling # Mandibular bone formation in lingual side # Mandibular bone formation in vestibular side Ubios et al, 1991;Pujadas Bigi et al, 2003 # Mandible growth (length and height) Diaz- Sylvester et al, 2002;Ubios et al, 1994 water and increased serum levels of type I collagen carboxy terminal telopeptide, a marker of bone resorption (ATSDR, 2013; Kurttio et al, 2005).…”