Male Rats Of Sprague-Dawley Strain Research Articles

Enhanced Fibrogenesis Activity in Diabetic Wound Using 20% Anredera scandens (L.) Moq. Leaves Extract Ointment in Sprague dawley Rats

Background: In diabetic conditions, decreased glucose-6-phosphate dehydrogenase activity results in reduced nitric oxide synthesis. Reduced nitric oxide synthesis results in the production of ROS. This may impede the processes of angiogenesis and vasoconstriction and prolong inflammation. Objective: We were interested in investigating the mechanism by which 20% of Anredera scandens leaves extract ointment increases fibrogenesis activity because this condition can affect the development of damaged skin tissue. This study's design is a post-test-only laboratory experiment. Material and methods: The study employed male Sprague dawley strain rats that were induced with 40 mg/kgBW of STZ. The mice were divided into four groups: the negative group (which got diabetic wounds only), the positive group (which got Gentamicin ointment), and the test group (which got 20% extract ointment). Results: The skin tissue from each group was then examined histopathologically. After receiving 20% ointment of Anredera scandens leaves extract, the test group's mean fibrogenesis histopathology score on day 14 was significantly higher (P=0.022) at 3.75 than that of the negative group, which had a mean score of 2.75. Following that, the skin tissue of both the extract test group and the normal group was examined histopathologically. In comparison to the normal group mean score of 4.0 on day 14, the test group, which received 20% ointment of Anredera scandens leaves extract, had a non-significant (P=0.317) mean fibrogenesis histopathology score of 3.75. Subsequently, skin tissue was examined histopathologically for both the positive and normal groups. According to the results, on day 14, the positive group's average fibrogenesis histopathology score was 3.5, while the normal group's average score was 4.0. This difference was not statistically significant (P=0.127). Conclusions: Thus, it can be said that 20% Anredera scandens leaf extract ointment is comparable to gentamicin ointment in its capacity to promote fibrogenesis activity in diabetic wounds.

Molecular Mechanism for Hepatic Glycerolipid Partitioning of n-6/n-3 Fatty Acid Ratio in an Obese Animal Biomodels.

The n-6/n-3 metabolic pathway associated with hepatic glycerolipid portioning plays a key role in preventing obesity. In this nutrition metabolism study, we used in vivo monitoring techniques with 40 obese male Sprague-Dawley strain rats attached with jugular-vein cannula after obesity was induced by a high-fat diet to determine the molecular mechanism associated with hepatic glycerolipid partitioning involving the n-6/n-3 metabolic pathway. Rats were randomly assigned to four groups (10 animals per group), including one control group (CON, n-6/n-3 of 71:1) and three treatment groups (n-6/n-3 of 4:1, 15:1 and 30:1). They were fed with experimental diets for 60 days. Incorporation rates of [14C]-labeling lipid into glycerolipid in the liver were 28.87-37.03% in treatment groups fed with diets containing an n-6/n-3 ratio of 4:1, 15:1 and 30:1, which were significantly (p < 0.05) lower than that in the CON (40.01%). However, 14CO2 emission % of absorbed dose showed the opposite trend. It was significantly (p < 0.05) higher in a treatment groups (n-6/n-3 of 4:1, 15:1 and 30:1, 30.35-45.08%) than in CON (27.71%). Regarding the metabolic distribution of glycerolipid to blood from livers, phospholipid/total glycerolipid (%) was significantly (p < 0.05) lower in CON at 11.04% than in treatment groups at 18.15% to 25.15%. Moreover, 14CO2/[14C]-total glycerolipid (%) was significantly (p < 0.05) higher in treatment groups at 44.16-78.50% than in CON at 39.50%. Metabolic distribution of fatty acyl moieties flux for oxidation and glycerolipid synthesis in the liver were significantly (p < 0.05) better in order of 4:1 > 15:1 > 30:1 than in the CON. Our data demonstrate that n-6/n-3 of 4:1 could help prevent obesity by controlling the mechanism of hepatic partitioning through oxidation and esterification of glycerolipid in an obese animal biomodel.

Effect of Pomegranate Juice against High Fat Diet Induced Fatty Liver in rats

This research aims at studying the effect of pomegranate juice against high fat diet induced fatty liver in rats. Forty adult male rats Sprague-Dawley strain, were divided into four groups of ten rats each weighing 180±20g. (G1) control group that were fed on standard diet, (G2) rats fed on standard diet with Pomegranate juice (20 ml/kg body weight orally) , (G3) rats fed on high fat diet, (G4) rats fed on high fat diet with pomegranate juice (20 ml/kg body weight orally). The experiment was conducted for 6 weeks. The incidence of fatty liver was evaluated by assayed the liver enzymes in serum (alanine aminotransferase and aspartate aminotransferase), serum lipid profile such as total cholesterol , high density lipoprotein cholesterol, triglycerides and histopathological examination of liver.The high fat diet group (G3), revealed hyperlipidemia, elevated in liver enzymes and histological changes in the liver tissue. While, the rats fed high fat diet with pomegranate juice group (G4), showed reduction in the levels of serum lipids and improvement in the liver enzymes. Furthermore, pomegranate juice reduced the occurrence of histological changes in rat's liver . The results of the study concluded that daily administration of pomegranate juice can protect against developing changes caused by high fat diet and reduced the development of fatty liver. These findings suggested that drinking pomegranate juice may be beneficial for people who are exposed to fatty liver or hypercholesterolemia. .

FRUCTOSE;

Objectives: To study and compare the effects of fructose and galactose on, bloodglucose, insulin, HbA and lipids and anthropometric measurements. Data Source: Ninety, 1chealthy adult male rats of Sprague-Dawley strain. Design: Experimental study. Setting:Department of Biochemistry and Molecular Biology, A.M.C, Rawalpindi, in collaboration withN.I.H, Islamabad. Period: Twelve months. Subjects and Methods: Rats weighing 180-350 gramswere selected by random sampling and were divided into three groups, 30 each. Group I wasgiven standard diet, Group II was given high fructose diet (HFD), i.e., 1.5gms/Kg body weight/dayof fructose, along with standard diet for two weeks and Group III was given high galactose diet,i.e., 0.83gms/Kg body weight/day, along with standard diet for two weeks. Results: There was asignificant increase in height of galactose group while fructose group has significant weight loss;BMI decreased in both but more in former. The blood levels of cholesterol, HDL-c, LDL-c, TG, andinsulin were significantly higher in fructose group than in galactose group. There was nosignificant difference between blood glucose and HbA among these groups yet their higher 1clevels indicate the chances of developing insulin resistance. Conclusions: Fructose due to itsless hyperglycaemic effects should not be used in diet and must not be prescribed in diabetes, asin the long run it can lead to obesity, hypertension and cardiovascular risk. Non-significant effectsof galactose on above parameters (except lipoproteins), does not mean that it can be used as analternative to fructose and this area needs exploration.

EFFECT OF BLACK RICE BRAN EXTRACT (Black Rice Bran) TO DECREASE DECREASE OF GLUCOSE LEVEL IN DIABETIC RATS

Black rice bran is one of processed foods derived from plants and has a decreasing effect of blood glucoselevels. Major component of anthocyanin in black rice bran that functions in lowering blood glucoseconcentration is cyanidin 3-glucoside. Fifteen male rats Sprague-Dawley strain were selected randomly anddivided into 5 groups with the same number in each groups. These groups were consisted of normal control,negative control, and black rice bran extract treatment with dose of 50, 100 and 200 mg/kg of bodyweight(b.w.). Each of them were induced to experience diabetes by alloxan 150 mg/kg of b.w. Measurement ofblood glucose levels was done by using visible spectrophotometer at 546 nm. The samples were collectedbefore and after alloxan injection, and after 4, 7, and 10 days later to observe the changes of blood glucoselevels. The results showed that black rice bran at 200 mg/kg of b.w. was able to lower the glucose levels,which amounted for 131,33 ± 8,08 mg/dL after 10 days of injection.

ETHANOLIC EXTRACTS OF HEDYOTIS CORYMBOSA L. IMPROVES MONOSODIUM IODOACETATE-INDUCE OSTEOARTHRITIS IN RAT

ABSTRACTObjective: The objective of this study is to explore the effects of the 70% ethanolic extract of pearl grass on the immune system of the osteoarthritismodel rat, characterized by the number of leukocytes and lymphocytes, and the histology of the joint. Osteoarthritis is a degenerative diseasecharacterized by chronic inflammation in the joints. Based on the daily practice of herbal medicine in some community in Indonesia, pearl grassusually used for anti-inflammation but not a lot of data to support it.Methods: We used 36 male rats Sprague-Dawley strain divided into 6 groups. Normal group was given 0.5% of CMC, the negative control group was given0.025 ml of sodium iodoacetate in 0.9% saline, the positive groups control group was given a suspension of glucosamine-chondroitin 135 mg/200 g bb,three were given pearls grass extract in various dose 5.625 mg, 11.25 mg, and 22.5 mg, respectively. 28 days after sodium iodoacetate induction, the extractswere given orally once daily for 21 days. Measurement of inflammation of knee joint and the number of leukocytes and lymphocytes were counted on day14th, 28th, and 49th after sodium iodoacetate induction. After treatment, all rats were sacrified and all knee joints were collected to subject for histology.Results: The results showed that the extract of pearl grass in all doses was able to decrease the number of leukocytes and lymphocytes significantlyand prevent proteoglycan degradation. The results showed that the extract of pearl grass with a given dose variations have antiinflammation effectand been able to protect proteoglycan significantly.Conclusion: Doses 3 (22.5 mg/200 g BW) is the best result. These results indicate that pearl grass can be further investigated as a treatment for osteoarthritis.Keyword: Osteoarthritis, Sodium iodoacetate, Pearl grass, Hedyotis corymbosa L. Lamk., Immune system.

Inhibitory Effects of Grape Seeds Powder, Extract and Oil on Gentamicin Induced Nephrotoxicity in Rats

This study was designed to determine the Inhibitory effect of grape seeds powder, extract and oil on gentamicin-induced nephrotoxicity in rats.The study was carried out on 30 adult albino male rats Sprague-Dawley strain were classified into two groups: The first group (n= 6) left as normal control group(-ve), fed on basal diet, the second group(n= 24) injected with gentamicin (100 mg/kg/day for 7 days i.p). These animals were divided into 4 groups 6 rats each of these , control (+ve) group and 3 groups were treated with grape seeds powder ( 10 % of diet ) , grape seeds extract (300mg/kg b.w.orally by stomach tube) and grape seeds oil (4 ml/kg b.w. orally by stomach tube) respectively. The treatment period was designed for eight weeks. The results revealed that, Gentamicin injection induced marked nephrotoxicity as evidenced by significant elevation in serum levels of creatinine, urea, uric acid, A/G ratio, MDA ,renin hormone, phosphorus and potassium, with significant reduction in serum levels of total protein, albumin, globulin, (SOD), (GPX), (GST) ,catalase antioxidant enzymes, erythropoietin hormone (EPO) , vitamin D and Ca . While the rat groups treated with grape seeds powder ,extract and oil showed significant improvement of the levels of serum total protein, albumin, globulin, kidney tissue superoxide dismutase (SOD), glutathione peroxidase (GPX), glutathione transferase (GST) , catalase antioxidant enzymes, erythropoietin hormone (EPO) and vitamin D, and significant decrease in serum creatinine, urea, uric acid, albumin/globulin ratio ,kidney tissue malondialdehyde (MDA), renin hormone, phosphorus and potassium compared with control(+ve) group. In conclusion, feeding rats with grape seeds powder ,extract and oil may significantly reduce nephrotoxicity, So this study recommend the use of grape seeds especially grape seeds oil or grape seeds extract for humans suffering nephrotoxicity, could be of value.

Anti-Inflammatory Activity of The Extract of Guava Leaves (Psidium guajava L) in The Rat (Rattus norvegicus L)

Using of natural sources that have anti-inflammatory activity for the prevention and treatment of degenerative diseases began to be further explored. An investigation on the anti-inflammatory activity of the aqueous extract of guava leaves (Psidium guajava L.) from Sawangan, Depok on white male rats of Sprague-Dawley strain had been carried out on the carrageenan-induced paw edema method. To examine the effect of guava extract on subcutan at different doses of 125, 250 and 500 mg/kg of body weight (BW). Indometacine at dose of 10 mg/kg BW was used as a positive control. Observations were made during five hours with an interval of one hour. These results demonstrate that the percentage of inflammation or edema (% E) optimal at the 4th hour and then decreased at the 5th hour, while the percentage of optimal inhibition occurred at the 5th hour. Guava extract at 125, 250 and 500 mg/kg BW reduced inhibitory percentage activities by 40.81, 55.45 and 43.61% (p< 0.05) respectively. In conclusion, this study suggests that guava extract has anti-inflammatory properties by decreasing edema level.Keywords: Anti-inflammatory, guava leaves, edema.

Properties of nanopowdered chitosan and its cholesterol lowering effect in rats

This study was carried out to compare the properties of nanopowdered chitosan (NPC) to commercially powdered chitosan (CPC) and examine the effect of NPC on serum and liver cholesterol lowering in rats. Twentyfour male rats of Sprague-Dawley strain were blocked into 3 groups and were raised for 8 weeks. High cholesterol diet, 2% CPC, or 2% NPC were given to 3 groups. NPC reduced total cholesterol by 46.6% and CPC reduced it by 18.6%. NPC also significantly reduced low density lipoprotein (LDL)-cholesterol by 55.7%, while CPC reduced by 36.8%. High density lipoprotein (HDL)-cholesterol content was increased more with NPC by 16.5% than with CPC by 9.6%. Triacylglycerol content was also decreased significantly by 42.8% with NPC, while reduced by 22.5% with CPC. The present study indicated that NPC feeding reduced total and LDL-cholesterol and triacylglycerol contents and increased HDL-cholesterol content.

Uji Efek Antiartritis Ekstrak Etanol 80% Kulit Buah Delima Merah (Punica granatum L) Terhadap Udem Pada Telapak Kaki Tikus Putih Jantan yang diinduksi oleh Complete Freund’s Adjuvant

Rheumatoid arthritis is a chronic inflammatory disease that can degrade the qualityof patient survival. Conventional treatments of this disease have potentially dangerousside effects. Therefore, many patients are turning to alternative medicine usingmedicinal herbs, one of which is the fruit of Punica granatum L. The aim of thisresearch was to determine antiarthritis effect of 80% ethanolic extract of Punica granatumL. fruit peel which had been given orally on 17-30th day based on decreased edemavolume and percentage indexes of arthritis. The method was adjuvant induced arthritisby using the complete freundrs adjuvant 0,1 mL by subplantar and allowed toarthritis until day 16. The animals test were used 33 male rats of Sprague Dawleystrain that were divided into six groups: normal control, positive control, negativecontrol, and three groups had received suspension of 80% ethanolic extract of Punicagranatum L. fruit peel in 0,5% CMC at doses 20, 40, and 80 mg/200 g body weight.The Edema volume was measured by pletismometer on days 17, 20, 23, 26, 29, 31and indexes of arthritis determined on days 17 and 31. The Results showed that theywere not significant difference in the decreased edema volume and the percentageindexes of arthritis, although the percentage inhibition of edema elevated with increasingdose.

Effect of etoricoxib, a cyclooxygenase-2 selective inhibitor on aberrant crypt formation and apoptosis in 1,2 dimethyl hydrazine induced colon carcinogenesis in rat model.

Etoricoxib, a second generation selective cyclooxygenase-2 (COX-2) inhibitor had been studied for the chemopreventive response at its therapeutic anti-inflammatory dose in 1,2-dimethylhydrazine (DMH) induced colon carcinogenesis in rat model. Eight to ten weeks old male rats of Sprague-Dawley strain were divided into four groups. While group 1 served as control and received the vehicle of the drugs, group 2 and 3 were administered freshly prepared DMH in 1mM EDTA-saline (pH 7.0) (30 mg/kg body wt/week, subcutaneously). Group 3 was also given a daily treatment of etoricoxib (0.6 mg/kg body wt orally) while the group 4 received the same amount of etoricoxib only, prepared in 0.5% carboxymethyl cellulose. Animals were sacrificed at the end of 6 weeks, body weight recorded and the colons were subjected to macroscopic and histopathological studies. The maximum number of raised mucosal lesions called the multiple plaque lesions (MPL) were found in the DMH group which significantly reverted back in the DMH + etoricoxib group, while very few MPLs were recorded in the control and etoricoxib only group. Similarly, the number of aberrant crypt foci (ACF), the point of future carcinogenic growth, was recorded more in the DMH group and significantly less in the DMH + etoricoxib group. The histopathological analysis showed the presence of severe hyperplasia, occasional dysplasia and aggregates of lymphoid cells in the localized regions. Etoricoxib group showed near normal histological features with the crypt architecture and the surrounding stromal tissue remaining intact. To ascertain the molecular mechanism of such anti-carcinogenic features the colonocytes were isolated and studied in primary culture for the evidence of apoptosis by fluorescent staining and genotoxic changes by single cell gel electrophoresis assay (comet assay) which shows that the DMH treated animals produced much less apoptotic nuclei but more comet producing cell, while these features were reverted back with the etoricoxib treatment. The cytoplasmic expression of COX-2 protein was studied in paraffin sections of the colon by immunohistochemistry with COX-2 specific antibody which showed a very high presence of this inducible enzyme with the DMH group while in all other groups of animals it was not visible or weekly expressed. The anti-inflammatory effect of the drug, etoricoxib was also validated by a carrageenan-induced inflammation in rat model which showed an extremely high anti-inflammatory response within the dose range used in the present study. Also the growth profile of all the animals remained the same throughout the six week period of the investigation as there was no change in the body weight. It appears that apoptosis remains the dominant anti-proliferative end effect of this drug, mediated by an inhibition of the proinflammatory COX-2 isoform although further molecular probings are needed to arrive at a conclusive agreement in favor of the chemoprotective use of such drugs in colon cancers.

Effects of lotus root and lotus leaf extracts on physical and sociopsychological stress in rats fed high fat diet

Lotus has been known to be effective in the lowering of hyperlipidemic levels. But, there have not been reports regarding the effects of lotus in lowering serum lipid levels under stress. The present study was designed to determine the possible effect of lotus root and leaf extracts on physical and sociopsychological stress in rats which were fed a high fat diet. The experiments were performed with the use of young (5 weeks of age) male rats of Sprague‐Dawley strain. The rats were fed with high fat diets and orally administered once a day 200 mg/kg body weight of lotus root extract for 8 weeks. Physical stress and sociopsychological stress were exposed by foot‐shock for 1 hour (10 sec duration at intervals of 60 sec) everyday for 3 weeks using a communication box. The rats were divided into seven groups: CON (without stress), FS (Foot‐shocked group), NFS (Nonfoot‐shocked group), FSR(Foot‐shocked with lotus root extracts), FSL (Foot‐shocked with lotus leaf extracts), NFSR (Nonfoot‐shocked with lotus root extracts) and NFSL (Nonfoot‐shocked with lotus leaf extracts). The final body weight of the rats in the groups of FS, FSR and FSL were lower compared to the CON group. Prolonged 3‐week physical stress resulted in reduced total body weight gains. Blood triglyceride and total‐cholesterol levels were decreased by physical stress and blood total‐cholesterol level was increased by sociopsychological stress. The lipid lowering effect was the most prominent in the FSL group. Blood lipid levels of the sociopsychological stress groups showed an increasing tendency when lotus root and lotus leaf extracts were administered. These results suggest that administration of lotus leaf extracts on physical stress was effective in reducing lipid levels in a high fat diet.

Effects of 12 Weeks of Exercise on Hepatic TNF-α and PPARα in an Animal Model of High-Fat Diet-Induced Nonalcoholic Steatohepatitis

Nonalcoholic steatohepatitis (NASH) is hepatic inflammation caused by a buildup of fat in the liver. This study was designed to examine whether the NASH-associated increase in hepatic TNF-α mRNA expression and serum TNF-α, and decrease in hepatic PPARα mRNA expression in rats secondary to 12-week consumption of a high-fat diet would be attenuated with concurrent exercise. A total of 28 male Sprague-Dawley strain rats were randomly assigned into four groups: standard diet without (C, n = 6) and with (E, n = 7) concurrent exercise; and high-fat diet without (H, n = 8) and with (HE, n = 7) concurrent exercise. The mean daily energy intake during the intervention period resulting from the standard and high-fat diets was approximately 82 kcal and 95 kcal, respectively. Swimming exercise was carried out in the E and HE groups for 12 weeks. The initial swimming duration of 30 minutes was progressively increased by 10 min·d −1 to 90 minutes by the end of the fourth week, which then remained unchanged. NASH revealed by histological activity index, which occurred in the H but not the C group, was alleviated in the HE group. Moreover, the upregulation of hepatic TNF-α mRNA expression and serum TNF-α, and downregulation of hepatic PPARα mRNA expression, which were shown in the H group, were attenuated in the HE group. Such findings suggest that long-term exercise carried out concurrently with consumption of a high-fat diet could alleviate high-fat diet-induced NASH. These may be partly attributable to the attenuation of hepatic TNF-α overexpression and the upregulation of hepatic PPARα mRNA expression.

Effects of dietary ascorbic acid supplementation on lipid peroxidation and the lipid content in the liver and serum of magnesium-deficient rats.

We investigated the effects of ascorbic acid (AsA) supplementation on lipid peroxidation and the lipid content in the liver and serum of magnesium (Mg)-deficient rats. Eighteen 3-week-old male Sprague-Dawley strain rats were divided into 3 groups and maintained on a control diet (C group), a low-Mg diet (D group), or a low-Mg diet supplemented with AsA (DA group) for 42 d. At the end of this period, the final body weight, weight gain, and serum Mg concentrations were significantly decreased in the Mg-deficient rats. Further, dietary AsA supplementation had no effect on the growth, serum Mg concentration, Mg absorption, and Mg retention. The serum concentration of AsA was significantly lower in the D group than in the C group but was unaltered in the DA group. The levels of phosphatidylcholine hydroperoxide (PCOOH) in the serum and of triglycerides (TGs) and total cholesterol (TC) in the serum and liver were significantly higher in the D group than in the C group. The serum PCOOH, liver TG, and liver TC levels were decreased in the DA group. These results indicate that Mg deficiency increases the AsA requirement of the body and that AsA supplementation normalizes the serum levels of PCOOH and the liver lipid content in Mg-deficient rats, without altering the Mg status.

Enhanced exudation of fibrinogen into the perivascular space in acute inflammation triggered by neutrophil migration.

The present experiments were performed to ascertain whether or not all plasma components are extravasated when vascular permeability is increased. Male Sprague-Dawley strain rats (specific pathogen-free) 8 weeks old (for histamine exudation) or 9-10 weeks old (for carrageenin pleurisy) were used. Histamine or A-carrageenin was injected into the rat right pleural cavity to induce rat pleurisy. Protein components in the inflammatory exudate and plasma were separated by high performance liquid chromatography. Coagulation time was assessed, and the fibrinogen levels in the pleural exudate were determined by thrombin time. The fibrinogen levels were also visualized by immunoblot analysis. Tumor necrosis factor-alpha (TNF-alpha, 0.4 microg/rat, intrapleurally), anti-rat CD18 monoclonal antibody (anti-CD18 antibody, 1 mg/kg, i. v.) and granulocyte-colony stimulating factor (G-CSF, 100 microg/kg, s.c. twice daily for 4 days) were used. In the histamine-induced extravasation, the level of plasma protein components with large molecules over 900 kD in the exudate was 62% of that in the rat's own plasma. The amount of fibrinogen in the pleural exudate was 1/8 of that in the plasma and was faintly detected in immunoblot analysis, but it was clearly detected after the treatment of rats with TNF-alpha. In rat carrageenin pleurisy, fibrinogen was hardly detected in immunoblot analysis in the exudate collected 0.5 h after carrageenin, when neutrophils did not migrate into the exudate. However, it was clearly present after neutrophil migration started 2 h later The increase in the neutrophil counts in the exudate caused by G-CSF enhanced the fibrinogen level in the exudate, whereas intravenous injection of anti-CD18 antibody suppressed the fibrinogen level in immunoblot analysis. Venular permeability increase in the rat histamine exudation induced minimal extravasation of plasma proteins with large molecules, such as fibrinogen, while fibrinogen molecule was detected in rat carrageenin-injected pleurisy, when neutrophil diapedesis occurred. Thus, only when neutrophils started to migrate into the perivascular space was fibrinogen clearly detected in the exudate.

ラット心筋の局所的ミオシンアイソザイム構成比に及ぼすランニングトレーニングの影響

We examined the effect of running training on regional cardiac myosin isozyme composition in rats. Male Sprague-Dawley strain rats (4 weeks old) were used, and divided into two groups: sedentary control (C) and trained (T) groups. The T group was trained by treadmill running (40 m/min, 1h/day, 5 days/week, for 12 weeks) . At 16 weeks old, their hearts were excised. The left ventricle was separated into the subendocardium (Endo) and subepicardium (Epi) by dissecting the ventricle at the mid-wall. The ventricular myosin isozymes were examined by electrophoresis on pyrophosphate gel under non-dissociating conditions. The results showed the following: 1) The relative heart weight of the T group was significantly higher than the C group. 2) Left ventricular myosin isozyme composition showed a region-specific distribution in the C rats, and the proportion of V3 myosin or β-myosin heavy chain in the Endo was significantly higher than that of the Epi. However, the training had no effect on the cardiac myosin isozyme in either portion. 3) The activity of citrate synthase did not show transmural gradient in the ventricle of C animals. Training had no effect on the activities of either portion. 4) The activity of lactate dehydrogenase (LDH) showed transmural gradient in the ventricle of C rats. Training-induced changes in the activity of LDH were found in both portions, therefore, training abolished the transmural gradient in the activity of LDH, suggesting a corresponding redistribution of the myocardial work load.These results indicate that running training might induce the redistribution of the myocardial work load, whereas the stimulation apparently has no effect on the regional distribution of cardiac myosin isozyme composition.

Nycthemeral variation in thermal dehydration-induced thirst

Temporal variation in spontaneous water intake in rats is well established but little is known about temporal variation in water intake following dehydration. In the present study different male Sprague-Dawley strain rats were exposed without water for 3 h to either a 25°C or a 40°C environment every 4 h for 20 h. The rats were then allowed access to water in a 25°C environment for 2 h. Rats exposed to 25°C showed significant temporal variation in evaporative water loss, urine output, urine sodium and potassium excretion, water intake, and percent rehydration with higher values occurring during the night. Rats exposed to 40°C had greater evaporative water loss, urine sodium excretion, feces output and water intake than the rats exposed to 25°C and had temporal variations which were similar to those of the rats exposed to 25°C. The robust effects of thermal-dehydration on water balance in rats are additive to rather than interactive with the effects of time of day.

Serum and alveolar bone phosphatase changes reflect bone turnover during orthodontic tooth movement

Acid and alkaline phosphatase changes have been demonstrated histochemically and biochemically during the early stages of an orthodontic tooth movement cycle. However, quantitative data on neither alveolar bone nor serum phosphatase changes over an entire tooth movement cycle have been reported. This study examined acid, tartrate-resistant acid (TRAP), and alkaline phosphatase changes in serum and alveolar bone during an orthodontic tooth movement cycle in 288 adult male Sprague-Dawley strain rats. The effect of differing initial force magnitudes on phosphatase changes was also examined. Data were obtained from four groups: sham control and three treatment groups (20, 40, and 60 gm activations). Each group (n = 72) was subdivided equally into six sacrifice subgroups (1,3,5,7,10, and 14 days). Treated animals received a precisely loaded orthodontic tipping force to the maxillary molars. Phosphatase measures were obtained by colorimetric assays. Analysis of variance (ANOVA) procedures were performed to examine for differences within groups across time and among groups at each time point. Data from treated animals were combined, adjusted for control values, and examined across time to permit comparisons with previously described histomorphometric changes. Analysis of variance indicated no differences occurred in the control group across time. Significant differences in serum values occurred across time within the force groups (p < 0.01), and among force and control groups at various times in both sera and bone (p < 0.05). In the pooled treatment data, a peak in serum acid phosphatase occurred at day 1 and in bone at day 3 (the later mirroring histomorphometric findings) (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Thermal dehydration-induced thirst in rats: role of angiotensin II

Dehydration can be brought about by either water deprivation or by heat exposure (thermal dehydration). Angiotensin II has been shown to have a role in water deprivation-induced thirst. The current study was designed to determine whether angiotensin II is involved in thirst caused by thermal dehydration. Male Sprague-Dawley strain rats were dehydrated by exposure to a 40 degree C environment for 2-4 h or by water deprivation for 44 h. Water deprivation but not heat exposure significantly increased plasma renin activity. Neither ureteric ligation nor nephrectomy significantly altered water intake after thermal dehydration. Captopril, an inhibitor of angiotensin converting enzyme, given at a dose of 100 mg/kg ip, significantly decreased water intake in water-deprived rats but not in thermally dehydrated rats. Angiotensin II therefore does not appear to play a role in the control of water intake of thermally dehydrated rats. The physiological responses to dehydration in rats are dependent on the way in which the dehydration is brought about.

Age-related changes in growth hormone releasing factor and somatostatin in the rat hypothalamus.

Distribution and staining intensities of growth hormone releasing factor (GR (GRF) and somatostatin (SRIF) were examined in young (3 months of age) and old (24 months of age) male rats of Sprague-Dawley strain, using the PAP immunocytochemical procedure. Some animals of each age group were intraventricularly injected with colchicine to demonstrate immunoreactive neuronal perikarya. GRF-immunoreactive intensities of old rats were markedly reduced in the median eminence as compared with those of young rats. No remarkable difference could be detected between SRIF immunoreactivities in the young and old animals, since intensive SRIF immunoreactivities were found in the external layer of the median eminence of both groups of animals. Between two age groups injected with colchicine, we also found no difference in the distribution and staining intensities of immunoreactive perikarya of GRF and SRIF in the hypothalamus and also detected no significant difference in total neuron numbers of each peptide. These findings suggest that the synthesis and/or release of GRF in GRF-containing neurons are decreased, though GRF-containing neurons themselves remain alive and have the capacity to synthesize GRF.