Efeitos da terapia combinada com ácido zoledrônico e propranolol na resistência mecânica em um modelo de rato com osteoporose por desuso / Effect of combined treatment with zoledronic acid and propranolol on mechanical strength in an rat model of disuse osteoporosis

Resumo Objetivos: Investigar os efeitos aditivos do agente antirreabsorção ácido zoledrônico (ZOL), isolado e em combinação ao propranolol (PRO), em um modelo de rato com osteoporose por desuso. Métodos: Usou-se um modelo de pata traseira direita de rato privada de descarga de peso para estudar as consequências da falta de descarga de peso sobre o esqueleto durante várias condições, como missões espaciais e repouso prolongado no leito em idosos. Ratos Wistar machos de três meses de idade foram submetidos à imobilização da pata traseira direita (IPTD) por 10 semanas para induzir à osteopenia; em seguida, foram divididos aleatoriamente em quatro grupos: 1 – IPTD para controle positivo; 2 – IPTD mais ZOL (50 μg/kg, dose única intravenosa); 3 – IPTD mais PRO (0,1 mg/kg, via subcutânea, cinco dias na semana); 4 – IPTD mais PRO (0,1 mg/kg, via subcutânea, cinco dias na semana) mais ZOL (50 μg/kg, dose única intravenosa) por outras 10 semanas. Um grupo de ratos não imobilizados foi usado como controle negativo. No fim do tratamento, os fêmures foram removidos e testaram-se a porosidade do osso e suas propriedades mecânicas, além do peso seco e das cinzas do osso. Resultados: No que diz respeito à melhoria da resistência mecânica da diáfise femoral média, a terapia combinada com ZOL mais PRO foi mais eficaz do que a monoterapia com ZOL ou PRO. Além disso, a terapia combinada com ZOL mais PRO foi mais eficaz na melhoria do peso seco do osso e preservou melhor a porosidade do osso cortical do que a monoterapia com ZOL ou PRO em ratos submetidos à imobilização da pata traseira direita. Conclusões: Esses dados sugerem que a terapia combinada com ZOL mais PRO deve ser recomendada para o tratamento da osteoporose por desuso.

Abstract Objectives: A model that uses right hind-limb unloading of rats is used to study the consequences of skeletal unloading during various conditions like space flights and prolonged bed rest in elderly. This study was aimed to investigate the additive effects of antiresorptive agent zoledronic acid (ZOL), alone and in combination with propranolol (PRO) in a rat model of disuse osteoporosis. Methods: In the present study, 3-month-old male Wistar rats had their right hind-limb immobilized (RHLI) for 10 weeks to induce osteopenia, then were randomized into four groups: (1) RHLI positive control, (2) RHLI plus ZOL (50 μg/kg, i.v. single dose), (3) RHLI plus PRO (0.1 mg/kg, s.c. 5 days per week), (4) RHLI plus PRO (0.1 mg/kg, s.c. 5 days per week) plus ZOL (50 μg/kg, i.v. single dose) for another 10 weeks. One group of non-immobilized rats was used as negative control. At the end of treatment, the femurs were removed and tested for bone porosity, bone mechanical properties, and bone dry and ash weight. Results: With respect to improvement in the mechanical strength of the femoral mid-shaft, the combination treatment with ZOL plus PRO was more effective than ZOL or PRO monotherapy. Moreover, combination therapy using ZOL plus PRO was more effective in improving dry bone weight and preserved the cortical bone porosity better than monotherapy using ZOL or PRO in RHLI rats. Conclusions: These data suggest that this combined treatment with ZOL plus PRO should be recommended for the treatment of disuse osteoporosis.

Efeito combinado do ácido zoledrônico e do alfacalcidol no tratamento da osteoporose por desuso em ratos / Additive effect of zoledronic acid and alfacalcidol in the treatment of disuse osteoporosis in rats

Objetivos: O desuso pelo repouso no leito, pela imobilização de membros ou por missões espaciais provoca a perda óssea rápida. Fez-se este estudo para investigar os efeitos terapêuticos do ácido zoledrônico (ZOL), isoladamente e em combinação ao alfacalcidol (ALF), em um modelo de rato com osteoporose por desuso. Métodos: Ratos Wistar machos de três meses foram submetidos à imobilização da pata traseira direita (IPTD) por 10 semanas para induzir a osteopenia; em seguida, foram divididos em quatro grupos: 1 – IPTD para controle positivo; 2 – IPTD mais ZOL (50 µg/kg, dose única intravenosa); 3 – IPTD mais ALF (0,5 µg/kg, via oral diariamente); 4 – IPTD mais ALF (0,5 µg/kg, via oral diariamente) mais ZOL (50 µg/kg, dose única intravenosa) por outras 10 semanas. Um grupo de ratos não imobilizados foi usado como controle negativo. No fim do tratamento, os fêmures foram removidos e testaram-se a porosidade do osso e suas propriedades mecânicas, além do peso seco e das cinzas do osso. Resultados: A terapia combinada com ZOL mais ALF foi mais eficaz em reduzir a porosidade do osso do que a monoterapia com um dos fármacos administrado isoladamente em ratos submetidos à IPTD. No que diz respeito à melhoria da resistência mecânica da diáfise femoral média, o tratamento combinado com ZOL mais ALF foi mais eficaz do que a monoterapia com um dos fármacos administrado isoladamente. Além disso, a terapia combinada com ZOL mais ALF foi mais eficaz na melhoria do peso seco e das cinzas do osso do que a monoterapia com ZOL ou ALF em ratos submetidos à IPTD. Conclusões: Esses dados sugerem que a terapia combinada com ZOL mais ALF representa uma opção terapêutica potencialmente útil para o tratamento da osteoporose por desuso. .

Objectives: Disuse by bed rest, limb immobilization or space flight causes rapid bone loss. We conducted the present study to investigate the therapeutic effects of zoledronic acid (ZOL), alone and in combination with alfacalcidol (ALF) in a rat model of disuse osteoporosis. Methods: In the present study, 3-month-old male Wistar rats had their right hind-limb immobilized (RHLI) for 10 weeks to induce osteopenia, then were divided into four groups: 1 – RHLI positive control; 2 – RHLI plus ZOL (50 µg/kg, i.v. single dose); 3 – RHLI plus ALF (0.5 µg/kg, oral gauge daily); 4 – RHLI plus ALF (0.5 µg/kg, oral gauge daily) plus ZOL (50 µg/kg, i.v. single dose) for another 10 weeks. One group of non-immobilized rats was used as negative control. At the end of the treatment, the femurs were removed and tested for bone porosity, bone mechanical properties, and bone dry and ash weight. Results: Combination therapy with ZOL plus ALF was more effective in decreasing bone porosity than each drug administered as monotherapy in RHLI rats. With respect to improvement in the mechanical strength of the femoral mid-shaft, the combination treatment of ZOL plus ALF was more effective than each drug administered as a monotherapy. Moreover, combination therapy using ZOL plus ALF was more effective in improving dry bone and ash weight, than single-drug therapy using ZOL or ALF in RHLI rats. Conclusions: These data suggest that combination therapy with ZOL plus ALF represents a potentially useful therapeutic option for the treatment of disuse osteoporosis. .

Efeitos combinados do ácido zoledrônico e do propranolol sobre a densidade óssea e marcadores bioquímicos de remodelação óssea em ratas osteopênicas submetidas à ovariectomia / Additive effects of zoledronic acid and propranolol on bone density and biochemical markers of bone turnover in osteopenic ovariectomized rats

Objetivos: Este estudo foi desenvolvido para investigar a eficácia e a segurança do ácidozoledrônico (ZOL) e do propranolol (PRO) como monoterapia e terapia combinada em ummodelo de rato com osteoporose pós-menopáusica. Métodos: Ratas Wistar fêmeas foram ovariectomizadas (OVX) ou submetidas à cirurgia simulada (placebo) aos três meses de idade. Doze semanas depois da cirurgia, as ratas foram divididas em seis grupos: (1) placebo + veículo; (2) OVX + veículo; (3) OVX + ZOL (100 µg/kg, dose única intravenosa); (4) OVX + ZOL (50 µg/kg, dose única intravenosa); (5) OVX + PRO (0,1 mg/kg, via subcutânea, cinco dias por semana); (6) OVX + ZOL (50 µg/kg, dose única intravenosa) + PRO (0,1 mg/kg, via subcutânea, cinco dias por semana) durante 12 semanas. Depois do tratamento, testou-se a densidade óssea, a porosidade e a microarquitetura tra-becular dos fêmures. Também foram avaliados marcadores bioquímicos séricos e urinários. Resultados: A terapia combinada com ZOL mais PRO foi mais eficaz em corrigir a diminuição do cálcio sérico e o aumento do nível sérico de fosfatase alcalina e fosfatase ácida resistenteao tartarato do que a monoterapia com ZOL ou PRO. Além disso, a terapia combinada comZOL mais PRO foi mais eficaz em corrigir o aumento dos níveis urinários de cálcio, fósforo ecreatinina do que a monoterapia com ZOL ou PRO. A terapia combinada com ZOL mais PRO também preservou a microarquitetura trabecular e a porosidade do osso cortical. Conclusão: Os resultados sugerem que a terapia combinada com ZOL mais PRO pode ser aabordagem mais eficaz para o tratamento da osteoporose grave em humanos. .

Objectives: The present study was designed to investigate further the efficacy and safety of zoledronic acid (ZOL) and propranolol (PRO) as monotherapy and combination therapy in a rat model of postmenopausal osteoporosis. Methods: Female Wistar rats were ovariectomized (OVX) or sham-operated at 3 months ofage. Twelve weeks post-surgery, rats were randomized into six groups: (1) sham + vehicle; (2) OVX + vehicle; (3) OVX + ZOL (100 뀅g/kg, i.v. single dose); (4) OVX + ZOL (50 뀅g/kg, i.v. single dose); (5) OVX + PRO (0.1 mg/kg, s.c. 5 days per week); (6) OVX + ZOL (50 뀅g/kg, i.v. single dose) + PRO (0.1 mg/kg, s.c. 5 days per week) for 12 weeks. After treatment, femurs were tested for bone density, porosity and trabecular micro-architecture. Biochemical markers in serum and urine were also determined. Results: Combined treatment with ZOL plus PRO corrected the decrease in serum calcium and increase in serum alkaline phosphatase and tartarate resistant acid phosphatase level better than single-drug therapy using ZOL or PRO. Moreover, combined treatment with ZOL plus PRO corrected the increase in urine calcium, phosphorous and creatinine level better than single-drug therapy using ZOL or PRO. Combination therapy using ZOL plus PRO also preserved the trabecular micro-architecture and cortical bone porosity. Conclusion: These data suggest that combined treatment with ZOL plus PRO could be a more effective approach for treating severe osteoporosis in humans. .

Additive effects of zoledronic acid and propranolol on bone density and biochemical markers of bone turnover in osteopenic ovariectomized rats.

OBJECTIVES: The present study was designed to investigate further the efficacy and safety of zoledronic acid (ZOL) and propranolol (PRO) as monotherapy and combination therapy in a rat model of postmenopausal osteoporosis. METHODS: Female Wistar rats were ovariectomized (OVX) or sham-operated at 3 months of age. Twelve weeks post-surgery, rats were randomized into six groups: (1) sham + vehicle; (2) OVX + vehicle; (3) OVX + ZOL (100 µg/kg, i.v. single dose); (4) OVX + ZOL (50 µg/kg, i.v. single dose); (5) OVX + PRO (0.1 mg/kg, s.c. 5 days per week); (6) OVX + ZOL (50 µg/kg, i.v. single dose) + PRO (0.1 mg/kg, s.c. 5 days per week) for 12 weeks. After treatment, femurs were tested for bone density, porosity and trabecular micro-architecture. Biochemical markers in serum and urine were also determined. RESULTS: Combined treatment with ZOL plus PRO corrected decrease in serum calcium and increase in serum alkaline phosphatase and tartarate resistant acid phosphatase level better than single-drug therapy using ZOL or PRO. Moreover, combined treatment with ZOL plus PRO corrected increase in urine calcium, phosphorous and creatinine level better than single-drug therapy using ZOL or PRO. Combination therapy using ZOL plus PRO also preserved the trabecular micro-architecture and cortical bone porosity. CONCLUSION: These data suggest that combined treatment with ZOL plus PRO could be more effective approach for treating severe osteoporosis in humans.

[Additive effect of zoledronic acid and alfacalcidol in the treatment of disuse osteoporosis in rats]. / Efeito combinado do ácido zoledrônico e do alfacalcidol no tratamento da osteoporose por desuso em ratos.

OBJECTIVES: Disuse by bed rest, limb immobilization or space flight causes rapid bone loss. We conducted the present study to investigate the therapeutic effects of zoledronic acid (ZOL), alone and in combination with alfacalcidol (ALF) in a rat model of disuse osteoporosis. METHODS: In the present study, 3-month-old male Wistar rats had their right hind-limb immobilized (RHLI) for 10 weeks to induce osteopenia, then were divided into four groups: 1- RHLI positive control; 2- RHLI plus ZOL (50 µg/kg, i.v. single dose); 3- RHLI plus ALF (0.5 µg/kg, oral gauge daily); 4- RHLI plus ALF (0.5 µg/kg, oral gauge daily) plus ZOL (50 µg/kg, i.v. single dose) for another 10 weeks. One group of non-immobilized rats was used as negative control. At the end of the treatment, the femurs were removed and tested for bone porosity, bone mechanical properties, and bone dry and ash weight. RESULTS: Combination therapy with ZOL plus ALF was more effective in decreasing bone porosity than each drug administered as monotherapy in RHLI rats. With respect to improvement in the mechanical strength of the femoral mid-shaft, the combination treatment of ZOL plus ALF was more effective than each drug administered as a monotherapy. Moreover, combination therapy using ZOL plus ALF was more effective in improving dry bone and ash weight, than single-drug therapy using ZOL or ALF in RHLI rats. CONCLUSIONS: These data suggest that combination therapy with ZOL plus ALF represents a potentially useful therapeutic option for the treatment of disuse osteoporosis.

Effect of combined treatment with zoledronic acid and propranolol on mechanical strength in an rat model of disuse osteoporosis.

OBJECTIVES: A model that uses right hind-limb unloading of rats is used to study the consequences of skeletal unloading during various conditions like space flights and prolonged bed rest in elderly. This study was aimed to investigate the additive effects of antiresorptive agent zoledronic acid (ZOL), alone and in combination with propranolol (PRO) in a rat model of disuse osteoporosis. METHODS: In the present study, 3-month-old male Wistar rats had their right hind-limb immobilized (RHLI) for 10 weeks to induce osteopenia, then were randomized into four groups: 1- RHLI positive control, 2- RHLI plus ZOL (50 µg/kg, i.v. single dose), 3- RHLI plus PRO (0.1mg/kg, s.c. 5 days per week), 4- RHLI plus PRO (0.1mg/kg, s.c. 5 days per week) plus ZOL (50 µg/kg, i.v. single dose) for another 10 weeks. One group of non-immobilized rats was used as negative control. At the end of treatment, the femurs were removed and tested for bone porosity, bone mechanical properties, and bone dry and ash weight. RESULTS: With respect to improvement in the mechanical strength of the femoral mid-shaft, the combination treatment with ZOL plus PRO was more effective than ZOL or PRO monotherapy. Moreover, combination therapy using ZOL plus PRO was more effective in improving dry bone weight and preserved the cortical bone porosity better than monotherapy using ZOL or PRO in right hind-limb immobilized rats. CONCLUSIONS: These data suggest that this combined treatment with ZOL plus PRO should be recommended for the treatment of disuse osteoporosis.

Descrição de um novo método de ooforectomia em ratas / Description of a new method of ovariectomy in female rats

Atualmente, os ratos são os animais de laboratório mais usados para investigar a osteoporose. Apresentamos um método eficiente de ooforectomia e o comparamos com dois outros comumente utilizados para indução experimental de osteoporose (incisão cutânea dorsal na linha média e abordagem dorsolateral dupla). Ratas Wistar de 12 semanas de idade foram divididas em três grupos. No grupo A, a ooforectomia foi precedida por uma única incisão cutânea dorsal na linha média de 3 cm de comprimento; no grupo B, por incisões dorsolaterais duplas de aproximadamente 1 cm de comprimento cada; e no grupo C, por uma única incisão ventral transversal de 0,4-0,6 cm na região abdominal média. Os pesos corporais médios dos animais nos grupos A, B e C foram 258,12 ± 0,54 g, 255,78 ± 0,42 g e 254,55 ± 1,69 g, respectivamente. Houve diferenças significativas quanto à duração (em minutos) da cirurgia nos grupos B (9,65 ± 0,86) e C (7,55 ± 0,11;P < 0,001) em comparação à do grupo A (15,52 ± 0,30), e no grupo B (P < 0,01) em comparação à do grupo C. Os tempos de cicatrização da ferida (em dias) nos grupos B (9,22 ± 0,67) e C (8,01 ± 0,93) foram significativamente menores que aquele no grupo A (11,58 ± 1,2;P < 0,001), sendo tal tempo no grupo C discretamente menor que no grupo B. A cirurgia, como conduzida no grupo C, foi tecnicamente mais fácil, consumiu menos tempo e apresentou cicatrização mais rápida de ferida.

Rats are currently the most used laboratory animals to investigate osteoporosis. We report an efficient method of ovariectomy and compared this method with the two other operative methods of ovariectomy (i.e., midline dorsal skin incision and double dorsolateral approach, which are used commonly for inducing experimental osteoporosis. Female Wistar rats, 12 weeks old, were divided into three groups. Ovariectomy was preceded by a single midline dorsal skin incision, 3 cm long, in the group A; double dorsolateral incisions, approximately 1 cm long, in the group B; and a single ventral transverse incision of 0.4-0.6 cm at the middle abdominal region in the group C. Animals in groups A, B, and C had a mean weight of 258.12 ± 0.54 g, 255.78 ± 0.42 g, and 254.55 ± 1.69 g, respectively. There were significant differences in the duration (in minutes) of surgery in the groups B (9.65 ± 0.86) and C (7.55 ± 0.11, P < 0.001) when compared to the group A (15.52 ± 0.30) and in the group B (P < 0.01) when compared to the group C. Wound healing time (in days) for groups B (9.22 ± 0.67) and C (8.01 ± 0.93) was significantly shorter than that for group A (11.58 ± 1.2, P < 0.001), with the wound healing time for group C being slightly shorter than that for group B. The surgery, as conducted in the group C, was technically easier, less time consuming and showed less wound healing duration.

Description of a new method of ovariectomy in female rats.

Rats are currently the most used laboratory animals to investigate osteoporosis. We report an efficient method of ovariectomy and compared this method with the two other operative methods of ovariectomy (i.e., midline dorsal skin incision and double dorsolateral approach, which are used commonly for inducing experimental osteoporosis. Female Wistar rats, 12 weeks old, were divided into three groups. Ovariectomy was preceded by a single midline dorsal skin incision, 3 cm long, in the group A; double dorsolateral incisions, approximately 1 cm long, in the group B; and a single ventral transverse incision of 0.4-0.6 cm at the middle abdominal region in the group C. Animals in groups A, B, and C had a mean weight of 258.12 ± 0.54 g, 255.78 ± 0.42 g, and 254.55 ± 1.69 g, respectively. There were significant differences in the duration (in minutes) of surgery in the groups B (9.65 ± 0.86) and C (7.55 ± 0.11, P < 0.001) when compared to the group A (15.52 ± 0.30) and in the group B (P < 0.01) when compared to the group C. Wound healing time (in days) for groups B (9.22 ± 0.67) and C (8.01 ± 0.93) was significantly shorter than that for group A (11.58 ± 1.2, P < 0.001), with the wound healing time for group C being slightly shorter than that for group B. The surgery, as conducted in the group C, was technically easier, less time consuming and showed less wound healing duration.

Medicamentos para o tratamento da osteoporose: revisão / Drugs for the management of osteoporosis: a review

A osteoporose caracteriza-se por reduzida massa óssea e deterioração microarquitetural do tecido ósseo, o que aumenta a fragilidade óssea e, portanto, a suscetibilidade a fraturas. A osteoporose é um importante problema de saúde pública, que leva a um maior risco de fraturas espontâneas e traumáticas. Na Índia, as fraturas osteoporóticas afetam ambos os sexos e podem ocorrer em idades mais precoces do que nos países do ocidente. Embora sem números precisos, mas com base nos dados disponíveis e na experiência clínica, estima-se que 36 milhões de indianos possam ser afetados pela osteoporose em 2013. Isso estaria associado a um custo enorme e a um consumo considerável de recursos da saúde. Terapias farmacológicas que reduzem de fato o número de fraturas através da melhora da massa óssea acham-se hoje disponíveis no mercado. Atualmente, a maioria dos medicamentos comercializados reduz a perda óssea através da inibição da reabsorção óssea, mas as terapias novas podem aumentar diretamente a massa óssea, como é o caso do paratormônio. As atuais alternativas de tratamento incluem bisfosfonatos, calcitonina, moduladores seletivos do receptor de estrogênio e inibidores da via RANK, sendo que níveis suficientes de cálcio e vitamina D são necessários. Novíssimos agentes tendo os osteoclastos como alvo, tais como a catepsina K e a Src quinase, estão sendo desenvolvidos. As terapias centradas nos osteoblastos incluem os agentes que atuam através da via de sinalização Wnt-β catenina, tais como os inibidores de Dkk-1 e antagonistas de esclerostina. Um maior conhecimento se faz necessário para melhorar as intervenções farmacológicas e as escolhas terapêuticas nesse campo.

Osteoporosis is characterized by low bone mass with micro architectural deterioration of bone tissue leading to enhance bone fragility, thus increasing the susceptibility to fracture. Osteoporosis is an important public health problem leading to an increased risk of developing spontaneous and traumatic fractures. In India osteoporotic fractures occur more commonly in both sexes, and may occur at a younger age than in the western countries. Although exact numbers are not available, based on available data and clinical experience, 36 million Indians may be affected by osteoporosis by 2013. This would be associated with enormous costs and considerable consumption of health resources. Pharmacological therapies that effectively reduce the number of fractures by improving bone mass are now available widely in markets. At present most drugs available in the markets decrease bone loss by inhibiting bone resorption, but the upcoming therapies may increase bone mass by directly increasing bone mass as is the case of parathyroid hormone. Current treatment alternatives include bisphosphonates, calcitonin, selective estrogen receptor modulators and inhibitors of RANK pathway but sufficient calcium and vitamin D are a prerequisite. Newer osteoclast targeted agents like cathepsin K and c-src kinase are under clinical development. The therapies which target osteoblasts include the agents acting through the Wnt-β catenin signaling pathway like Dkk-1 inhibitors and sclerostin antagonists. To further improve pharmacological interventions and therapeutical choices in this field, improvement of knowledge is very necessary.

Drugs for the management of osteoporosis: a review.

Osteoporosis is characterized by low bone mass with micro architectural deterioration of bone tissue leading to enhance bone fragility, thus increasing the susceptibility to fracture. Osteoporosis is an important public health problem leading to an increased risk of developing spontaneous and traumatic fractures. In India osteoporotic fractures occur more commonly in both sexes, and may occur at a younger age than in the western countries. Although exact numbers are not available, based on available data and clinical experience, 36 million Indians may be affected by osteoporosis by 2013. This would be associated with enormous costs and considerable consumption of health resources. Pharmacological therapies that effectively reduce the number of fractures by improving bone mass are now available widely in markets. At present most drugs available in the markets decrease bone loss by inhibiting bone resorption, but the upcoming therapies may increase bone mass by directly increasing bone mass as is the case of parathyroid hormone. Current treatment alternatives include bisphosphonates, calcitonin, selective estrogen receptor modulators and inhibitors of RANK pathway but sufficient calcium and vitamin D are a prerequisite. Newer osteoclast targeted agents like cathepsin K and c-src kinase are under clinical development. The therapies which target osteoblasts include the agents acting through the Wnt-ß catenin signaling pathway like Dkk-1 inhibitors and sclerostin antagonists. To further improve pharmacological interventions and therapeutical choices in this field, improvement of knowledge is very necessary.