Histological analysis of the effects of electroacupuncture stimulation on the femur fracture line in a rat model of hindlimb immobilization / 全日本鍼灸学会雑誌

[Introduction] This study compared the effects of joint immobilization and concurrent electroacupuncture stimulation on fracture line appearance, which is indicative of differences in cortical bone structure, in the femurs of young adult rats. [Materials and Methods] Forty-two 7-week-old Wistar rats were divided into three groups: a hindlimb immobilized group (IM), a hindlimb immobilized group with concurrent electroacupuncture stimulation (IMEA), and an untreated control group (CO). IM and IMEA were immobilized for two weeks with a jacket-type immobilization device that immobilized the hip joint in extension and restricted hip joint adduction and abduction. Acupuncture needles were inserted into the femoral region during the immobilization period in the IMEA group, and continuous alternating current was used for stimulation. A low-frequency stimulator was used to generate electrical current (250 μsec, 50 Hz, 0.24 mA, 500 Ω load resistance), and stimulation was performed daily for two weeks at 10 min/day. The extracted femur was fractured from the anterior part of the diaphysis or metaphyseal end by three-point-bending under constant conditions with 10 mm between the fulcrum and a crosshead speed of 10 mm/min. [Results] IM showed significantly lower Stiffness, Deformation, and Strength values than CO. Bone morphometry parameters also showed lower values for IM. A cement line was observed between lamellar and non-lamellar bone in CO and IMEA, but was indistinct in IM. In CO and IMEA, minute bone fragments were formed in the deep diaphysis region sandwiched between the inner and outer circumferential lamellae, but no such fragments were found in IM. IMEA had less resorption than IM, and lamellar bone with a structure similar to CO was maintained. Moreover, cracks observed in CO and IMEA ran longitudinally in the vicinity of the cement line and rest line, but no such cracks were found in IM. [Discussion and Conclusion] These findings suggest that electroacupuncture mitigates bone weakening in immobilized rat femurs, and this affects the appearance of the fracture line.

Absorción mineral y retención ósea en ratas normales en crecimiento por el consumo de un yogur experimental reducido en lactosa que contiene galactooligosacáridos (GOS) / Mineral absorption and bone retention in normal growing rats by consumption of an experimental lactose-reduced yogurt containing galactooligosaccharides (GOS)

Introducción: Los GOS son prebióticos naturales presentes en la leche materna que pue-den obtenerse enzimáticamente a partir de la lactosa de leche de vaca durante la fabricación de yogur. El producto lácteo resultante será reducido en lactosa y contendrá prebióticos y bacterias potencialmente probióticas. Sin embargo, mantendrá la baja relación Ca/Pi que aporta la leche de vaca, lo que podría alterar el remodelamiento óseo y la mineralización. Objetivo: comparar si un yogur reducido en lactosa que contiene GOS (YE) ofrece ventajas adicionales respecto de un yogur regular sin GOS (YR) sobre las absorciones (Abs) de Ca y Pi, retención y calidad ósea durante el crecimiento normal. Al destete, ratas machos fueron divididas en 3 grupos alimentados con AIN ́93-G (C), YE o YR durante 28 días. Resultados: YE mostró el mayor aumento de lactobacilos fecales; producción de ácidos grasos de cadena corta especialmente p, profundidad de las criptas colónicas y menor pH cecal. El %AbsCa y %AbsPi aumentó en el siguiente órden: YE> YR> C (p < 0,05). El contenido de Ca y Pi en fémur, la densidad y contenido mineral óseos y los parámetros biomecánicos fueron similares en YE y C, mientras que YR mostró valores significativa-mente menores (p < 0,05). Conclusiones: YE aumentó las Abs y biodisponibilidad de minerales, alcanzando la retención y calidad ósea de C. El aumento en las Abs observado en YR no logró obtener la retención y calidad ósea de C. Conclusión: YE habría contrarrestado el efecto negativo del mayor aporte de Pi de la leche de vaca y sería una buena estrategia para lograr el pico de masa ósea y calidad del hueso adecuados, especialmente en individuos intolerantes a la lactosa. (AU)

Breast milk contains an optimal calcium/phosphate (Ca/Pi) ratio and GOS. These natural prebiotics can be enzymatically produced via cow's milk lactose inyogurt manufacture. This milk product is low in lactose and contains prebiotics and potentially probiotic bacteria but maintains a low Ca/Pi ratio that could alter bone remodeling and mineralization. We evaluated if a lactose-reduced yogurt containing GOS (YE) offers additional advantages over regular yogurt without GOS (YR) on Ca and Pi absorption (Abs), bone retention and quality during normal growth. Weaning male rats were divided into 3 groups fed AIN'93-G (C), YE or YR for 28 days. Results: YE showed the highest increase in fecal lactobacilli; short-chain fatty acids production, especially propionate and butyrate; intestine crypt depth, and the lowest cecal pH. AbsCa% and AbsPi% increased in this order: YE> YR> C (p <0.05). Ca and Pi content in femur, bone density and mineral content, and biomechanical parameters were similar in YE and C, while YR showed the significantly lowest value (p < 0.05). Conclusions: YE increased mineral Abs reaching the retention and bone quality of C. Although YR increased Abs, bone retention and quality did not achieve C values. Seemingly, YE compensated for the negative effect of the higher Pi supply and would be a good strategy to achieve adequate peak bone mass and bone quality, especially in lactose intolerant individuals. (AU)

Possible effects of whole body vibration on bone properties in growing rats

OBJECTIVES: To examine the effects of whole body vibration (WBV) on bone properties in growing rats, and to explore the optimal conditions for enhancing bone properties. METHODS: Thirty-six 4-week-old male rats were divided into 1 control and 5 experimental groups. Each experimental group underwent WBV at 15, 30, 45, 60, and 90 Hz (0.5 g, 15 min/d, 5 d/wk) for 8 weeks.We measured bone size, muscle weight and bone mechanical strength of the right tibia. Trabecular bone mass and trabecular bone microstructure (TBMS) of the left tibia were analyzed by micro-computed tomography. Serum levels of bone formation/resorption markers were also measured. RESULTS: WBV at 45 Hz and 60 Hz tended to enhance trabecular bone mass and TBMS parameters. However, there was no difference in maximum load of tibias among all groups. Serum levels of bone resorption marker were significantly higher in the 45-Hz WBV group than in the control group. CONCLUSIONS: WBV at 45–60 Hz may offer a potent modality for increasing bone mass during the period of rapid growth. Further studies are needed to explore the optimal WBV conditions for increasing peak bone mass and TBMS parameters. WBV modality may be a potent strategy for primary prevention against osteoporosis.

High fructose and high fat diet increased bone volume of trabecular and cortical bone in growing female rats / 한국영양학회지

PURPOSE: The objective of this study was to investigate the effects of a high fructose and fat diet on bone growth and maturation in growing female rats. METHODS: Three-week-old female SD rats were randomly assigned to four experimental groups; the control group (CON: fed control diet based on AIN-93G, n = 8); the high-fructose diet group (HFrc: fed control diet with 30% fructose, n = 8); the high-fat diet group (Hfat: fed control diet with 45 kcal% fat, n = 8); and the high-fat diet plus high fructose group (HFrc + HFat: fed diets 45 kcal% fat with 30% fructose, n = 8). Each group was assigned their respective diets for the remaining eight weeks. Bone-related parameters (bone mineral density (BMD) and structural parameters, osteocalcin (OC), deoxypyridinoline (DPD)) and morphologic changes of kidney were analyzed at the end of the experiment. RESULTS: Final body weights and weight gain were higher in the HFat and HFrc + HFat groups and showed higher tendency in the HFrc group compared with those of the CON group (p < 0.05); however, no significant difference in caloric intake was observed among the four experimental groups. The serum OC levels of the HFrc and HFrc + HFat groups were lower than those of the CON and HFat groups (p < 0.05). Urinary levels of DPD did not differ among the experimental groups. BV/TV and Tb.N of trabecular bone were higher in the HFrc + HFat group and showed a higher tendency in the HFrc group than those of the CON and HFat groups (p < 0.05). Tb.Pf of trabecular bone were lower in the HFrc + HFat group than those in the CON and HFat groups (p < 0.05). However, no difference in trabecular BMD was observed among the experimental groups. Cortical bone volume was higher in the HFat and HFrc + HFat groups than in the CON and HFrc groups (p < 0.05). No morphology change in kidney was observed among the experimental groups. CONCLUSION: Our study suggests that 8 weeks of high-fructose and high fat intake could improve the bone quality (Structural parameters) of trabecular and cortical bone of tibia in growing female rats.

Comparative effect of cane syrup and natural honey on abdominal viscera of growing male and female rats.

The high intake of refined sugars, mainly fructose has been implicated in the epidemiology of metabolic diseases in adults and children. With an aim to determine whether honey can substitute refined sugars without adverse effect, the long-term effects of natural honey and cane syrup have been compared on visceral morphology in growing rats fed from neonatal age. Honey increased the caecum and pancreas weights in male rats, which could enhance enzymatic activities of pancreas and digestive functions by intestinal microflora of caecum. Unlike honey, cane syrup caused fatty degenerations in the liver of both male and female rats. Honey enhanced intestinal villi growth, and did not cause pathology in the rodents’ abdominal viscera, suggesting potential nutritional benefit as substitution for refined sugars in animal feed.

The Effect of Dietary Protein Source and Sulfur Amino acid Content on bone Metabolism in Growing Rats

This study was performed to evaluate the effect of dietary protein source and sulfur amino acid content on bone metabolism in rats. Thirty male rats (body weight 145 +/- 2 g) were divided into three groups. The rats in the first group were fed on casein 20% diet as animal protein source and those in the second group were fed on soy 20% diet as plant protein source. Sulfur amino acid ratio of these group was 1.07 : 1. The rats in the third group were fed on soy 20% diet and the sulfur amino acid were supplemented with the amount contained as much in the soy 20% diet. All rats were fed on experimental diet and deionized water ad libitum for 9 weeks, The total body, spine, femur bone mineral density and bone mineral content were measured using Dual Energy X-ray Absorptiometry. Calcium, phosphate, pyridinoline, creatinine in urine and calcium, phosphate, alkaline phosphatase, osteocalcin in serum were measured. During the experimental period, plant protein (soy protein) group had a lower urinary Ca excretion, urine pyridinoline & crosslinks value and had a higher Ca efficiency in total bone and femur bone mineral density than animal protein (casein) group. There were no significant differences in serum calcium, phosphate, alkaline phosphatase and osteocalcin among the three groups of the rats. The findings from this study demonstrated that plant protein (soy protein) is beneficial of bone mineral density because it had a higher Ca efficiency in total bone and femur bone mineral density than animal protein (casein). However, the supplementation of sulfur amino acid on soy results were consistent with prior studies that dietary sulfur amino acid load had a negative effect on calcium balance. The rats fed sulfur amino acid supplementation diet increased urinary calcium excretion and decreased calcium efficiency for total and femur mineral density. Therefore, dietary protein source and sulfur amino acid content influence bone metabolism.

ARTERIAL BARORECEPTOR REFLEX IN GROWING RATS / 体力科学

In order to characterize the neural control of the circulation in an organism undergoing a rapid somatic growth, we compared the arterial baroreceptor reflex in two groups of male Wistar rats anesthetized with urethane. The first group consisted of 36 rats of 6-7 weeks old, known to exhibit the greatest rate of increase of the body weight during the life span, whereas the second group consisted of 30 full-grown rats of 20-22 weeks old. When arterial pressure was controlled by phenylephrine or nitroglycerin, the reflex change in renal nerve activity was elicited over the arterial pressure range 15-30 mmHg lower than that of full-grown rats. The difference was attributable partly, but not exclusively, to the lower operating range of arterial baroreceptors in the former groups. Although no difference was observed between the two groups with respect to the reflex fall in arterial pressure in response to graded electrical stimulation of the aortic nerve, the accompanying bradycardia was significantly smaller in 6-7 weeks old rats primarily due to the difference in the vagally mediated component of the reflex response. In conclusion, the arterial baroreceptor reflex of growing rats, as compared to full-grown counterparts, is characterized by deviation of the operating range of arterial baroreceptors as well as the arterial baroreceptor reflex itself to lower arterial pressure range and poor development of the vagally mediated reflex bradycardia.