• The korean journal of orthodontics
• /
• v.19 no.3
• /
• pp.15-33
• /
• 1989

The purpose of this study was to investigate changes of the mandible of a growing rat when they are subjected to a retractive force and those after removal of the retractive force. The experimental animals were Sprague-Dawley male rats of four weeks of age. A mandible was retracted with 50 grams of force on each side in the posterior and superior direction for 8 hours per day. The animals were sacrificed after 1 week, 2-week and 4-week force application, and after 4-week force application-4-week force removal period. The changes of rat mandibular growth following retractive force on the growing rat mandible were observed histologically and biometrically. The findings were as follows ; 1. Histologically, the thickness of the condylar cartilage was slightly reduced in the anterosuperior region with the retractive force. However, in the group of 4-week force application-4-week force removal, there was no significant difference in the thickness of the condylar cartilage. 2. There were no significant histological changes in the articular disk and glenoid fossa through the experimental period. 3. The length and anterior height of the mandible subjected to the retractive force were significantly smaller and greater than those of the control group. 4. There were no significant differences in the mandibular length between 4-week force application - 4-week force removal and the control group. 5. It was concluded that a mandibular retractive force produced inhibitory effects in the growth of the mandible, but that these effects were not sustained during mandibular growth in this experimental model.

• Journal of Community Nutrition
• /
• v.6 no.1
• /
• pp.48-54
• /
• 2004

The purpose of this study was to examine the effects of dietary protein and exercise on bone mineral density and bone mineral content of growing male rats. Forty male, Sprague-Dawley rats(age 21 days) were assigned to four groups that underwent 9 weeks of experimental treatment. Animals were assigned to one of two exercise treatments (treadmill running or sedentary). The exercise and nonexercise group were fed a diet containing casein or soy with rich isoflavones (3.4mg/g protein). The exercise group ran on a rodent treadmill(speed of 15m/min for 30min) three days per week during the 9-week study period. All rats were fed an experimental diet and deionized water ad libitum for 9 weeks. Total bone mineral density (BMD), total bone mineral content (BMC), total body calcium, spine BMD and BMC, and femur BMD and BMC were determined by using dual energy x-ray absorptiometry (FIXI-mus, GE Lunar Radiation Cooperation, Madison, WI, USA). The soy diet group appears to have a significantly higher total BMD/weight and total BMC/ weight, spine BMD/weight, spine BMC/weight, femur BMD/weight and femur BMC/weight compared to the casein group in nonexercise and exercise. The exercise group had significantly greater total BMD/weight and BMC/ weight, spine BMD/weight and BMC/weight, femur BMD/weight and BMC/weight compared to the nonexercise group when the protein source was casein. The exercise combined soy group had significantly greater total BMD/weight and BMC/weight, spine BMD/weight and BMC/weight, femur BMD/weight and BMC/weight, compared to the exercise combined casein group. The results indicate that exercise had a positive influence on bone mineral density and bone mineral content and soy significantly affect on bone mineral density and bone mineral content for the 9 weeks experimental period. It can be concluded that exercise combined with a soy diet is most beneficial for acquisition of spine bone mineral density in young growing male rats. This convincing evidence suggests that a change in life style such as increasing exercise and consumption of soy protein is a practical strategy for significantly reducing the incidence of osteoporosis.

• Clinical and Experimental Reproductive Medicine
• /
• v.39 no.4
• /
• pp.144-152
• /
• 2012

Objective: Concerns are growing about the decrease in male reproductive health. Caffeine is one of the popular nutrients that has been implicated as a risk factor for infertility. In the present study, we examined whether in utero and lactational exposure to caffeine affects the reproductive function of the offspring of rats. Methods: Pregnant rats received caffeine via drinking water during gestation (26 and 45 mg/kg) and lactation (25 and 35 mg/kg). Body and reproductive organ weight, seminiferous tubule diameter, germinal epithelium height, sperm parameters, fertility rate, number of implantations, and testosterone level of the offspring were assessed from birth to adulthood. Results: Significant dose-related decreases were observed in the body and reproductive organ weight, seminiferous tubule diameter, and germinal epithelium height of the offspring. Sperm density had declined significantly in offspring of the low-dose and high-dose groups, by 8.81% and 19.97%, respectively, by postnatal day 150. The number of viable fetuses had decreased significantly in females mated with male offspring of the high-dose group at postnatal days 60, 90, 120, and 150. There were also significant reductions in testosterone levels of high-dose group offspring from birth to postnatal day 150. Conclusion: It is concluded that maternal caffeine consumption impairs gonadal development and has long-term adverse effects on the reproductive efficiency of male offspring rats.

• Journal of Nutrition and Health
• /
• v.5 no.4
• /
• pp.177-187
• /
• 1972

The effect of three different grains supplemented diet as a dietary carbohydrate source on the growing rat, growth, food intake, FER and PER value, excretion of urinary arid fecal nitrogen and glucose and the level of glucose and cholesterol in serum blood was studied. Forty males and same number of females of Albino rats weighing male $58{\pm}2g$, female$62{\pm}2g$ were divided into eight experimental group, five male and female in each and fed rice diet, rice supplemented with wheat and rice supplemented with barley diet for 14 weeks. Under this condition wheat supplemented diet group shows the best FER, PER and body weight gain value. Especially in female group shows better FER, PER and body weight gain value compare to control diet group. Under the male groups wheat supplemented diet group shows lower FER, PER value and body weight compare to the control group but higher than those of barley diet group or rice alone. In female group the nitrogen retention shows also highest value by wheat supplemented diet group. By male group the wheat supplemented diet group shows not better value compare to the control group, but higer than barley supplemented group or rice alone. The nitrogen excretion through feces was significantly higher by grain supplemented diet group compare to grain the 20% sugar casein diet. The blood cholesterol content was slightly decreased by the control group which was fed disaccaride, compare to groups which were fed polysaccaride. But the free cholesterol to esterified cholesterol ratio shows lower value by control group than grain groups except the 70% rice supplemented with 30% barley group.

• Journal of Embryo Transfer
• /
• v.31 no.3
• /
• pp.169-177
• /
• 2016

There is a growing interest in the application of primary hepatocytes for treatment of liver diseases in humans and for drug development. Several studies have focused on long-term survival and di-differentiation blocking of primary hepatocytes in an in vitro culture system. Therefore, the present study also aimed to optimize an in vitro culture system using primary rat hepatocytes. Primary rat hepatocytes from 6-week-old male Crl:CD rats were isolated using a modified two-step collagenase perfusion. Healthy $3.5{\times}10^6$ primary rat hepatocytes were seeded into a 2 dimensional (2D) culture in a 25T culture flask coated with collagen type I or into a 3D culture in a 125-ml spinner flask for 7 days. Production of plasma protein (ALB and TF), apoptosis (BAX and BCL2), and CYP (CYP3A1) related genes were compared between the 2D and 3D culture systems. The 3D culture system had an advantage over the 2D system because of the relatively high expression of ALB and low expression of BAX in the 3D system. However, the level of CYP3A1 did not improve in the 3D culture with and without the presence of a dexamethasone inducer. Therefore, 3D culture has an advantage for albumin production and primary rat hepatocyte survivability, but a low expression of CYP3A1 indicated that primary rat hepatocytes require a high-density culture for stress reduction by continuous flow.

• Korean Journal of Pharmacognosy
• /
• v.39 no.2
• /
• pp.80-85
• /
• 2008

Benign prostatic hyperplasia (BPH) is one of the common diseases in elderly men. Recently, the old-aged population has increased, with the interest in the clinical importance of BPH ever growing. This study is designed to investigate the effects of KH-305 on BPH induced rat. The herb formulation KH-305 is consisted of Rubus coreanus, Cornus officinalis and Cuscuta chinensis. An experimental prostatic hyperplasia was induced in male rats by the administration of testosterone propionate, 3 mg/kg SC, for 2 months. The rats were divided into 3 experimental groups: the control, BPH-induced, oral KH-305 ingestion group. After 2 months, the prostates were removed, and analyzed for their prostatic weight and histological examination. The prostate weights were measured in each group, and found to be 820${\pm}$38mg, 3140${\pm}$26mg, 1880${\pm}$21mg in the control, BPH-induced, and oral KH-305 ingestion group, respectively. The BPH induced group showed statistically significant increases in their prostatic weights compared with control group(p<0.05) but oral KH-305 ingestion group showed more significant decreases than BPH-induced group statically(p<0.05). Histologically injected testosterone lead to prostatic hyperplasia in rats, but oral KH-305 ingestion decreased this change. These results suggest that KH-305 may be effective in treatment of BPH, and complementary medicine of BPH.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.16 no.2
• /
• pp.63-68
• /
• 1987

The effects of various levels of copper(Cu) intake on the concentrations of copper, iron (Fe) and 3inc(Zn) in rat tissues were studied in growing rats. For different groups the drinking water was supplemented with 0(control), 25, 50, 100 and 200ppm Cu(as copper sulphate) for 1 day respectively. All animal groups were fed with the control diet (Cu contents, 12.8%mg/kg diet) during the experiment. At the end of the 4 week experiment, body weight gain was slightly lower in the Cu supply groups than in control group. Liver and serum Cu were significantly higher in 50, 100 and 200ppm Cu of male and in 200ppm Cu of female than in control groups. Spleen Cu was significantly increased by the supplementation of Cu. Liver and heart Fe of male and heart Fe of female were increased by incresing supplementary Cu levels. In 50ppm Cu group, liver, spleen and kidney Fe of female increased but the others did not. Fe of tissues was different in male and female rats according to Cu levels supplied. Serum Zn of male and female was significantly lower in 50, 100 and 200ppm Cu groups than in control and 25ppm Cu groups. When supplemented with Cu levels there were no significant differences among groups for liver, kidney, spleen and heart Zn as well as heart and kidney Cu.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.11 no.1
• /
• pp.57-68
• /
• 1982

In order to investigate the effect of dietary protein and energy on growing female and male rats, Sprague-Dawley 90 female rats and 54 male rats of 3 weeks old weighing approximately 70-80g and 65-75g, respectively, were subjected to feeding trials for 8 weeks and then subsquently to metabolic trials for 2 weeks. Three dietary energy levels (3200, 3600, 4000 kcal ME/kg) were employed and each energy level contained three protein levels (15, 25, 35% of 3600 kcal ME/kg) and three fat levels (10, 20, 40% of 3600 kcal ME/kg) by addition of an appropriate amount of carbohydrate and the following results were obtained. The body weight gain of female rats was highest for LPHE ration but that of male rats was highest for LPME ration. The weight gains both of female and male rats were not affected by the level of protein. Food efficiencies both of female and male rats was affected by the level of protein, whereas that of male rats was not. Protein efficiencies of female and male rats were highest at low protein level and tended to decrease as the level of protein increased, but that of female rats was highest at high energy level, while that of male rats was highest at medium energy level. The analysis of the body composition after feeding trials for 8 weeks has shown that the contents of body water and protein were not affected by protein level both in female and male rats. The content of body fat increased remarkably as the protein and energy levels increased in case of female rats, but it was not affected by the protein and energy levels in case of male rats. From the above-mentioned experimental results it may be con eluded that the best formula of diet of growing female rats may be composed of low protein (13%) and high energy levels (4000 kcal/kg) whereas that for male rats may be composed of low protein (13%) and medium energy levels (3600 kcal/kg), since all the efficiencies of food, protein and energy have shown to be best at these levels.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.12 no.3
• /
• pp.264-272
• /
• 1983

In order to investigate the effect of dietary protein and energy on growing female and male rats, Sprague-Dawley 90 female rats and 54 male rats of 3 weeks old weighing approximately 70-80g and 54-75g, respectively, were subjected feeding trials for 8 weeks and then subsequently to metabolic trials for 2 weeks. Three dietary energy levels(3,200, 3,600, 4,000 kcal/kg) were employed and each energy level contained three protein levels (15, 25, 35% of 3600 kcal ME/kg) and three rat levels (10, 20, 40% of 3,600 kcal ME/kg) by addition of an appropriate amount of carbohydrate and the following result were obtained. As the protein level was increasing, digestibilities of dry matter and carbohydrate tended to decrease whereas that of protein was slightly increasing. On the other hand, digestibility of fat was always very high regardless of the level of protein but that tended to be slightly improved as the level of energy or rat increased. The digestibilities of female and male rats tended to be same. The digestibilities of dry matter, crude protein, crude fat and carbohydrate were 83%, 90%, 96% and 93%, respectively, and they were neither affected by protein and energy levels nor observed differently depending upon the sex. Nitrogen retention of female and male rats were best for LPHE ration. In other words, both nitrogen retention was improved as the level of energy increased and the level of protein decreased. The gross energy intake was high at low protein level in female rats and at medium protein level in male rats. That tended to decrease as the level of energy increased in female rats whereas that was not affected by the level of energy in male rats. The metabolic energy efficiency was highest for LPHE ration in female rats and for LPME ration in male rats.

• Reproductive and Developmental Biology
• /
• v.34 no.2
• /
• pp.89-94
• /
• 2010

Melatonin is induced by light information through the retina and leads to growth factor activation. Thus, we investigated the effects of melatonin by controlling the photoperiod of growing young rats. Male Sprague-Dawley rats (n=6; 4 weeks old) were divided into two experimental groups: the L/D group (normal photoperiod; light/dark: 12/12 h; lights on at 9:00 a.m.) and the L/L group (light/light: 24 h). Rat body weight and food consumption were measured daily for 8 weeks. After 8 weeks, the rats were anesthetized with a mixture of ketamine (50 mg/kg) and xylazine (10 mg/kg) and sacrificed. Tissue was then collected for RNA isolation (from brain, heart, liver, kidney, adrenal gland, testis, tibia, hind limb muscles). Also, serum was isolated from blood using a centrifugal separation. The L/L group had significantly lower body weight than the L/D group from 4 to 6 weeks (p<0.05). The L/D group had increased tissue mass, compared with the L/L group, but the difference was not statistically significant. The L/D group had a significantly higher melatonin concentration than the L/L group between the hours of midnight and 2:00 a.m (p<0.01). These results indicate that photoperiod length may affect the secretion of melatonin from the pineal gland. Also, the reduction of nocturnal melatonin secretion may retard the development of growing young rats. In future studies, we plan to compare exogenous melatonin administration with endogenous melatonin concentration induced by photoperiod control. Moreover, we will confirm whether the effects seen in pathological animal models can be reversed by controlling the photoperiod.