Recombinant human insulin-like growth factor-1 promotes osteoclast formation and accelerates orthodontic tooth movement in rats.

BACKGROUND: IGF-1 may be an important factor in bone remodeling, but its mechanism of action on osteoclasts during orthodontic tooth movement is complex and unclear. METHODOLOGY: The closed-coil spring was placed between the left maxillary first molar and upper incisors with a force of 50 g to establish an orthodontic movement model. Eighty SD rats were randomized to receive phosphate buffer saline or 400 ng rhIGF-1 in the lateral buccal mucosa of the left maxillary first molar every two days. Tissue sections were stained for tartrate-resistant acidic phosphatase (TRAP), the number of TRAP-positive cells was estimated and tooth movement measured. RESULTS: The rhIGF-1 group exhibited evidential bone resorption and lacuna appeared on the alveolar bone compared to the control group. Moreover, the number of osteoclasts in compression side of the periodontal ligament in the rhIGF-1 group peaked at day 4 (11.37±0.95 compared to 5.28±0.47 in the control group) after the orthodontic force was applied and was significantly higher than that of the control group (p<0.01). Furthermore, the distance of tooth movement in the rhIGF-1 group was significantly larger than that of the control group from day 4 to day 14 (p<0.01), suggesting that rhIGF-1 accelerated orthodontic tooth movement. CONCLUSION: Our study has showed that rhIGF-1 could stimulate the formation of osteoclasts in the periodontal ligament, and accelerate bone remodeling and orthodontic tooth movement.

Recombinant human insulin-like growth factor-1 promotes osteoclast formation and accelerates orthodontic tooth movement in rats

Abstract Background: IGF-1 may be an important factor in bone remodeling, but its mechanism of action on osteoclasts during orthodontic tooth movement is complex and unclear. Methodology: The closed-coil spring was placed between the left maxillary first molar and upper incisors with a force of 50 g to establish an orthodontic movement model. Eighty SD rats were randomized to receive phosphate buffer saline or 400 ng rhIGF-1 in the lateral buccal mucosa of the left maxillary first molar every two days. Tissue sections were stained for tartrate-resistant acidic phosphatase (TRAP), the number of TRAP-positive cells was estimated and tooth movement measured. Results: The rhIGF-1 group exhibited evidential bone resorption and lacuna appeared on the alveolar bone compared to the control group. Moreover, the number of osteoclasts in compression side of the periodontal ligament in the rhIGF-1 group peaked at day 4 (11.37±0.95 compared to 5.28±0.47 in the control group) after the orthodontic force was applied and was significantly higher than that of the control group (p<0.01). Furthermore, the distance of tooth movement in the rhIGF-1 group was significantly larger than that of the control group from day 4 to day 14 (p<0.01), suggesting that rhIGF-1 accelerated orthodontic tooth movement. Conclusion: Our study has showed that rhIGF-1 could stimulate the formation of osteoclasts in the periodontal ligament, and accelerate bone remodeling and orthodontic tooth movement.

Effect of N-acetylcysteine in liver ischemia-reperfusion injury after 30% hepatectomy in mice.

PURPOSE: Evaluate the effect of N-acetylcysteine in liver remnant after hepatectomy associated to ischemia-reperfusion injury in mice. METHODS: Male adult BALB/c mice, weighing 20-22 g were used. Animals were anesthetized with ketamine (70 mg/kg) and xylazine (10 mg/kg); received N-acetylcysteine (150 mg/kg, H-IR-NAC group) or vehicle (H-IR group). Surgical procedures were performed under 10X magnification. Partial hepatectomy (30%) was followed by ischemia-reperfusion injury (30 minutes of ischemia and 60 minutes of reperfusion). Blood sample and liver tissue were removed before animal was euthanized. AST and ALT were evaluated in blood samples and histomorphological analyses were performed in remnant liver. Groups were compared by Mann-Whitney test, and it was considered significant when p<0.05. RESULTS: Biochemical evaluations showed reduced levels of ALT in NAC group (H-IR-NAC=376 ± 127 U/l vs H-IR=636 ± 39 U/l, p=0.023). AST was similar (p=0.456). H-IR group showed hepatic tissue with preserved architecture, large area of steatosis, vascular congestion and rare mitogenic activity. NAC group showed hepatic tissue with small area of steatosis, vascular congestion and elevated mitogenic activity, evidenced by increased binuclear cells (H-IR-NAC=15.88 ± 0.52 vs H-IR=7.4 ± 0.37, p<0.001). CONCLUSION: N-acetylcysteine promotes enzymatic and morphological protection against hepatectomy and ischemia-reperfusion injury.

Effect of N-acetylcysteine in liver ischemia-reperfusion injury after 30% hepatectomy in mice / Efeito da N-acetilcisteína na lesão hepática por isquemia e reperfusão após 30% de hepatectomia em camundongos

PURPOSE: Evaluate the effect of N-acetylcysteine in liver remnant after hepatectomy associated to ischemia-reperfusion injury in mice. METHODS: Male adult BALB/c mice, weighing 20-22g were used. Animals were anesthetized with ketamine (70 mg/kg) and xylazine (10 mg/kg); received N-acetylcysteine (150 mg/kg, H-IR-NAC group) or vehicle (H-IR group). Surgical procedures were performed under 10X magnification. Partial hepatectomy (30%) was followed by ischemia-reperfusion injury (30 minutes of ischemia and 60 minutes of reperfusion). Blood sample and liver tissue were removed before animal was euthanized. AST and ALT were evaluated in blood samples and histomorphological analyses were performed in remnant liver. Groups were compared by Mann-Whitney test, and it was considered significant when p<0.05. RESULTS: Biochemical evaluations showed reduced levels of ALT in NAC group (H-IR-NAC=376±127U/l vs H-IR=636±39U/l, p=0.023). AST was similar (p=0.456). H-IR group showed hepatic tissue with preserved architecture, large area of steatosis, vascular congestion and rare mitogenic activity. NAC group showed hepatic tissue with small area of steatosis, vascular congestion and elevated mitogenic activity, evidenced by increased binuclear cells (H-IR-NAC=15.88±0.52 vs H-IR=7.4±0.37, p<0.001). CONCLUSION: N-acetylcysteine promotes enzymatic and morphological protection against hepatectomy and ischemia-reperfusion injury.

OBJETIVO: Investigar se a N-acetilcisteína promove proteção do remanescente hepático após ressecção associada à isquemia e reperfusão do fígado em camundongos. MÉTODOS: Foram utilizados 12 camundongos BALB/c, machos, pesando entre 20-22g. Os animais foram anestesiados com quetamina (70mg/kg) e xilazina (10mg/kg); receberam a N-acetilcisteína (150mg/kg, grupo H-IR-NAC) ou controle (grupo H-IR). Os procedimentos cirúrgicos ocorreram na magnificação de 10X. A lesão por isquemia e reperfusão (30 minutos de isquemia e 60 minutos de reperfusão) foi precedida pela hepatectomia de 30%. Foram utilizados como parâmetro de avaliação: a bioquímica sangüínea (AST e ALT) e a histologia do fígado (coloração de hematoxilina-eosina). Para avaliação estatística empregou-se o teste de Mann-Whitney e o nível de significância foi 5%. RESULTADOS: Na avaliação bioquímica houve redução no nível de ALT no grupo tratado (H-IR-NAC=376±127 U/l vs H-IR=636±39 U/l, p=0,023). AST foi similar (p=0,456). Na histologia, o grupo H-IR apresentou um tecido hepático com arquitetura preservada, com grandes áreas de infiltração gordurosa, presença de congestão vascular e de alguma atividade mitótica; o grupo com a N-acetilcisteína apresentou menor infiltração gordurosa e congestão vascular, maior atividade mitótica, evidenciada pela quantidade elevada de células binucleadas (H-IR-NAC=15,88±0,52 vs H-IR=7,4±0,37, p<0,001). CONCLUSÃO: A N-acetilcisteína promove proteção ao fígado, do ponto de vista morfológico e enzimático, após hepatectomia associada à isquemia e reperfusão.

Effect of N-acetylcysteine in liver ischemia-reperfusion injury after 30% hepatectomy in mice / Efeito da N-acetilcisteína na lesão hepática por isquemia e reperfusão após 30% de hepatectomia em camundongos

PURPOSE: Evaluate the effect of N-acetylcysteine in liver remnant after hepatectomy associated to ischemia-reperfusion injury in mice. METHODS: Male adult BALB/c mice, weighing 20-22g were used. Animals were anesthetized with ketamine (70 mg/kg) and xylazine (10 mg/kg); received N-acetylcysteine (150 mg/kg, H-IR-NAC group) or vehicle (H-IR group). Surgical procedures were performed under 10X magnification. Partial hepatectomy (30%) was followed by ischemia-reperfusion injury (30 minutes of ischemia and 60 minutes of reperfusion). Blood sample and liver tissue were removed before animal was euthanized. AST and ALT were evaluated in blood samples and histomorphological analyses were performed in remnant liver. Groups were compared by Mann-Whitney test, and it was considered significant when p<0.05. RESULTS: Biochemical evaluations showed reduced levels of ALT in NAC group (H-IR-NAC=376±127U/l vs H-IR=636±39U/l, p=0.023). AST was similar (p=0.456). H-IR group showed hepatic tissue with preserved architecture, large area of steatosis, vascular congestion and rare mitogenic activity. NAC group showed hepatic tissue with small area of steatosis, vascular congestion and elevated mitogenic activity, evidenced by increased binuclear cells (H-IR-NAC=15.88±0.52 vs H-IR=7.4±0.37, p<0.001). CONCLUSION: N-acetylcysteine promotes enzymatic and morphological protection against hepatectomy and ischemia-reperfusion injury.(AU)

OBJETIVO: Investigar se a N-acetilcisteína promove proteção do remanescente hepático após ressecção associada à isquemia e reperfusão do fígado em camundongos. MÉTODOS: Foram utilizados 12 camundongos BALB/c, machos, pesando entre 20-22g. Os animais foram anestesiados com quetamina (70mg/kg) e xilazina (10mg/kg); receberam a N-acetilcisteína (150mg/kg, grupo H-IR-NAC) ou controle (grupo H-IR). Os procedimentos cirúrgicos ocorreram na magnificação de 10X. A lesão por isquemia e reperfusão (30 minutos de isquemia e 60 minutos de reperfusão) foi precedida pela hepatectomia de 30%. Foram utilizados como parâmetro de avaliação: a bioquímica sangüínea (AST e ALT) e a histologia do fígado (coloração de hematoxilina-eosina). Para avaliação estatística empregou-se o teste de Mann-Whitney e o nível de significância foi 5%. RESULTADOS: Na avaliação bioquímica houve redução no nível de ALT no grupo tratado (H-IR-NAC=376±127 U/l vs H-IR=636±39 U/l, p=0,023). AST foi similar (p=0,456). Na histologia, o grupo H-IR apresentou um tecido hepático com arquitetura preservada, com grandes áreas de infiltração gordurosa, presença de congestão vascular e de alguma atividade mitótica; o grupo com a N-acetilcisteína apresentou menor infiltração gordurosa e congestão vascular, maior atividade mitótica, evidenciada pela quantidade elevada de células binucleadas (H-IR-NAC=15,88±0,52 vs H-IR=7,4±0,37, p<0,001). CONCLUSÃO: A N-acetilcisteína promove proteção ao fígado, do ponto de vista morfológico e enzimático, após hepatectomia associada à isquemia e reperfusão.(AU)