Paronychia argentea Lam. protects renal endothelial cells against oxidative injury.

ETHNOPHARMACOLOGICAL RELEVANCE: Paronychia argentea Lam. (Arabic tea), a species spontaneously growing in the Mediterranean area, has been used in folk medicine for renal diseases. AIM OF THE STUDY: To assess the antioxidant and protective potentials of different extracts from P. argentea in the renal endothelial NRK-52E cell line by several in vitro models, including a H2O2-induced oxidative stress model. MATERIAL AND METHODS: Aerial parts of P. argentea were collected in Algeria and ethanolic, chloroform and aqueous-chloroform extracts were obtained from dried plant. The antioxidant capacity was first evaluated by the Oxygen Radical Absorbance Capacity (ORAC) and the free radical scavenging activity (DPPH) methods. Cellular viability was assessed by MTT method assay after 24 h pretreatment with each extract concentration in order to measure protection from H2O2 in NRK-52E cells. Furthermore, the intracellular ROS formation (DCFH-DA method), was determined. RESULTS: P. argentea showed in vitro antioxidant activity as evidenced by the ORAC and DPPH assays. No cell toxicity was observed for concentrations ranging from 0.1 to 100 µg/mL of each extract. These extracts also exerted a protective effect on renal endothelial cells simultaneously treated with 1 mM H2O2. Chemical composition for the aqueous-chloroform extract was assessed by HPLC, as it showed the strongest antioxidant ability, revealing three quercetin derivatives as the main phenolic compounds. CONCLUSION: P. argentea is endorsed with antioxidant activity and protects renal endothelial cells against oxidative damage which indicate this plant constitutes a potential treatment for renal diseases.

Effects of Fiber Purified Extract of Carob Fruit on Fat Digestion and Postprandial Lipemia in Healthy Rats.

Increased postprandial lipemia is a cardiovascular disease (CVD) risk factor. Carob fruit extract (CFE) contains condensed tannins, and their intake has been inversely related to CVD. The objective was to evaluate the in vitro pancreatic lipase activity in the presence of CFE and the in vivo effect of CFE on postprandial lipemia of healthy Wistar rats in acute and subchronic digestibility studies and to relate it with changes in fat digestion and absorption. CFE significantly reduced pancreatic lipase activity. A peak delay and a dose-dependent decrease in plasma triglyceride and cholesterol areas under the curve were observed, effects that increased after the subchronic treatment. The levels of nondigested, nonabsorbed triglycerides of the remaining intestinal lumen fat were significantly higher in the maximum dose of CFE administrated versus the control ( P < 0.05). This study demonstrates for the first time the hypolipemic properties of CFE from the first administration, modifying postprandial lipemia by reducing the extents of fat digestion and absorption.

Fiber purified extracts of carob fruit decrease carbohydrate absorption.

The postprandial state plays a central role in the development and setting of chronic diseases. Condensed tannins (CT) are polyphenols with a known ability to modify carbohydrate digestion and absorption. The high concentration of CT in the pulp of carob fruit suggests a potential antidiabetic effect. The aim of this work was to analyze the in vitro and in vivo effects of carob fruit extract (CFE) on the digestion and absorption of carbohydrates. α-Glucosidase activity and glucose diffusion were tested in vitro using 0.5, 1, 2 and 5 mg mL-1 CFE concentrations. Two in vivo absorption studies, acute and subchronic, were carried out in four groups of 6 two-month-old male Wistar rats (control and CFE 25, 50 and 150 mg per kg b.w.), administering 1 mL of olive oil and 0.5 g per kg b.w. of glucose solution by oral gavage. CFE significantly inhibited α-glucosidase activity, through a competitive mechanism, from 1 mg mL-1, and also reduced glucose diffusion in a dose-dependent manner. In the acute study, CFE (50 and 150 mg per kg b.w.) significantly reduced the area under the curve (AUC) of blood glucose. Subchronic CFE administration induced further AUC decreases; and CFE at 150 mg per kg b.w. reduced sodium-glucose-linked transporter-1 (SGLT1) levels in the duodenum. This study demonstrates the hypoglycemic properties of CFE, highlighting its potential role as a suitable nutritional strategy in diabetic patients.

Growth hormone modulates the degradative capacity of muscle nucleases but not of cathepsin D in post-weaning mice.

We determined whether recombinant human growth hormone (rhGH) administration might modulate the enzyme degradative capacity of the muscle lysosomal system and influence muscle growth. Muscle cathepsin D, acid RNase and DNase II activities are determined in the gastrocnemius muscle of rhGH-treated post-weaning female BALB/c mice. Linear regressions were used to analyze the relationships of each enzyme with their respective substrate. GH induced a depletion-recovery response of muscle growth through a mechanism which is similar to catch-up growth. In these conditions, cathepsin D activity decreased with age in all animals (GH: 40%; saline: 79%), showing a substantial developmental decline that could reflect changes in the rate of protein breakdown. However, the degradative capacity of cathepsin D was paradoxically unmodified in rhGH-mice compared with saline mice (according to the enzyme vs. substrate linear regression slope), in spite of the increase in enzyme activity elicited by GH. This suggests that the muscle protein breakdown is not increased by GH-treatment in post-weaning mice. The enhancement of muscle protein deposition as indicated by the augmented muscle cell size (protein:DNA ratio) of rhGH-mice (increased 178% from 25 to 50 days) vs. saline, can be attributed to a higher muscle K(RNA). In contrast, acid RNase and DNase II activities directly participate in muscle RNA and DNA degradation. Both nucleases were inhibited by GH treatment (a decrease of 48% and 63%, respectively, vs. saline at 50 days). The decrease in RNase activity suggests an inverse relation between the rate of protein synthesis (high) and acid RNase activity (low), leading to spare muscle RNA for synthesizing protein during catch-up growth. Also, low DNase II activity could contribute to inhibiting of muscle DNA degradation, facilitating muscle growth. Thus, GH seems to act as a direct modulator of the degradative capacity of skeletal muscle nucleases but not of cathepsin D, influencing DNA and RNA degradation during the depletion-recovery response to GH of gastrocnemius muscle in female post-weaning mice.

The modulator effect of GH on skeletal muscle lysosomal enzymes is dietary protein dependent.

OBJECTIVE: The purpose of this work is to determine whether changes in dietary protein level could alter the modulator effect that GH has on the muscle lysosomal system by influencing the hydrolytic activities of cathepsin D, acid RNase and DNase II and the participation of these enzymes in muscle growth. DESIGN: BALB/c female mice were fed a diet containing 20% (HP) or 12% (MP) protein ad libitum and were treated with either saline (s) or rhGH (GH) (74 ng/g) for 29 days. Body weight and feed intake were recorded daily. At 25, 30, 35, 40, 45 and 50 days of age, five mice from each group were slaughtered and nucleic acids and protein concentrations and cathepsin D, acid RNase and DNase II activities in gastrocnemius muscle were analysed. Correlation coefficients were used to analyse the links between the activity of each enzyme with its substrate. RESULTS: GH-treatment induced a depletion-recovery response in muscle growth through a compensatory mechanism. Changes in protein content, DNA and RNA concentrations were related to changes in lysosomal enzyme activities. Muscle cathepsin D activity in saline mice fell as the dietary protein concentration increased. GH-treatment reversed this effect by enhancing the proteolytic activity in muscle of well-fed mice and inhibiting it in mice fed a 12% protein diet. This inversion appears to be related to the different mechanism elicited by GH-treatment on skeletal muscle protein growth in each dietary group. An opposite trend was observed in muscle acid nuclease activities. Acid RNase and DNase II increased according to the dietary protein concentration, since a 12% protein diet induced a lower catabolism, especially on muscle DNA of saline mice. In contrast, GH-treatment decreased acid RNase and DNase II activities, but only in mice fed a 20% protein diet, perhaps leading to spare muscle RNA for protein synthesis, as well as to the inhibition of DNA degradation during catch-up growth. A lower dietary protein concentration appeared to reverse the GH protective effect on nucleic acids. CONCLUSIONS: GH seems to act as a dietary protein-dependent modulator of the skeletal muscle lysosomal enzyme activity. These lysosomal enzymes play a role during muscle growth in GH-treated post-weaning mice by modifying muscle protein and DNA and RNA degradation.

Dietary protein concentration correlates in a complex way with glucose metabolism and growth performance in pregnant rats.

We studied the influence of dietary protein concentration (PC) on the adaptation mechanism of maternal glucose metabolism to gestation, and on maternal body weight (BW) gain using pregnant rats fed 4% (low protein, LP), 10% (medium protein, MP) or 20% (high protein, HP) dietary protein concentration. Feed (FI), energy (EI) and protein (PI) intakes were recorded. Plasma glucose, insulin and GH were determined, and insulin:glucose (insulin resistance) and insulin:GH ratios computed. Correlation and regression analyses were used to determine the physiological relationships between metabolic and ponderal variables. MP dams with greater FI and EI (12%), and lower PI (44%) than HP dams showed similar maternal and fetal growth performance because of the maintained energy efficiency (EE). LP dams, with similar FI and EI, and lower PI (81%) than HP dams, failed to catch up due to the low EE. PC exerted a non-linear influence on BW gain, insulin and GH, through EI and EE modifications. The EI linearly influenced hormone concentrations with the maximum and minimum hormone response in MP and LP dams, respectively. Insulin resistance increased as PC decreased, whereas the GH lipolytic effect appeared to predominate over insulin action. Circulating hormones and metabolites affected nutrient partitioning between dam and fetus, with the result that the competing demands for materno-fetal growth of HP and MP dams, but not the LP dams, were satisfied. A deeper knowledge of the nature of the materno-fetal energy relationships will enhance the manipulation of the growth performance of the fetus in several animal species.

Body growth and substrate partitioning for fat and protein gain in weaned BALB/c mice treated with growth hormone.

Previously we have found that recombinant human growth hormone (rhGH) (GH; 74 ng g body wt.(-1)) administration to weaned BALB/c male mice (fed 12% or 20% protein diet) induced a growth lag and subsequent repletion similar to the catch-up growth process. We studied the partitioning of feed and protein intakes between adipose and protein body stores through the linear relationships among them. The non-linear relationship of protein intake with body fat gain/protein gain (FG/PG) ratio was especially adequate in determining the partitioning of substrates. rhGH induced an increase in feed and protein intake utilization for body weight gain (50%) and fat gain (75-140%) over saline; macronutrient utilization was the greatest in rhGH-treated mice fed 20% protein. However, growth recovery of rhGH mice was anomalous and protein intake was derived primarily for fat gain. Mice fed 12% protein (treated and control) also derived protein intake in preference to fat stores. Treatment and diet had a cumulative effect with the result that rhGH-treated animals fed 12% protein showed the greatest FG/PG ratio (1.6), and therefore, the lowest efficiency to gain protein. Weaning is a critical stage in mice when treating with rhGH, as this could provoke a growth lag. The study showed that a high protein level is required to surpass the rhGH-induced lag, but it is not enough to obtain an enhanced protein deposition. Feeding a 12% protein diet was even worse as mice did not improve on the growth lag and substrates were directed mainly to body fat.

Growth hormone administration produces a biphasic cellular muscle growth in weaning mice.

The present study was undertaken to elucidate the effect of the exogenous administration of rhGH on the time course of the cellular muscle growth in male and female BALB/c mice fed 20% dietary protein between weaning and 50 days of age. Also, the efficiency of utilization of protein and energy intake to muscle DNA content and protein per cell (protein to DNA ratio) storage were studied. 120 weaned mice (21 d) were assigned to four groups based on rhGH-treatment (rhGH-treated: 7.4 ng x g(-1) BW and control: saline vehicle; via s.c. every two days) and gender. Feed intake was measured daily. At 25, 30, 35, 40, 45 and 50 days of age twenty mice were killed by cervical dislocation and the samples of gastrocnemius muscles were isolated, weighed and protein and DNA contents were measured. The rhGH administration caused a biphasic response altering the muscle cellular growth as a consequence of age-specific feed intake changes. The GH-induced fall of feed intake between 25 and 30 days of age caused decreases in muscle weight and myonuclei number (DNA), whereas muscle cell size was maintained. Later on, the self-controlled increase of feed intake led to the muscle weight recovery to control level, in spite of the irreversible DNA fall, as a consequence of the increase of cellular protein deposition and an enhancement of utilization of protein and energy intakes to deposit protein per cell. These results demonstrate that in spite of the initial (25-30 d of age) muscle DNA fall, rhGH-administration from weaning ensures the recovery of cellular muscle growth to control level through a compensatory muscle hypertrophy.

Feed intake and protein skeletal muscle in growing mice treated with growth hormone: time course effects.

The exogenous recombinant human growth hormone (rhGH) administration on gastrocnemius muscle growth performance and its contribution to body growth of male and female BALB/c mice fed a 12 % protein diet from 25 to 50 days of age, as well as the mechanism of utilization of feed intake to the lean muscle deposition were studied. Male and female weaning mice (21 days of age) were injected subcutaneously for 29 days with rhGH (74 ng x g(-1)) or saline vehicle (control). Feed intake and body weight (BW) were measured daily. At 25, 30, 35, 40, 45 and 50 days of age twenty mice were killed by cervical dislocation and the gastrocnemius muscle was isolated, weighed and the protein content was measured. The rhGH administration caused a biphasic response of BW and muscle growth as a consequence of age-specific feed intake changes. The initial feed intake fall induced the allometric proportion decreases in both muscle growth versus body growth and protein muscle versus muscle growth. That effect was due to ineffient utilization of energy and protein intake on protein muscle store. Later on, the self-controlled increase of feed intake leads to the recovery of muscle weight to control values, through nutrient partitioning toward non protein tissue showing a compensatory muscle growth. This suggests that a higher dietary protein level should be necessary for promoting the protein anabolic effect of GH during weaning.

Recombinant human growth hormone modifies the inherent partition of nutrients in growing female and male BALB/c mice.

BALB/c mice weaned at 21 days were used to investigate the effects of exogenous recombinant human growth hormone (rhGH) administration on the growth performance and carcass composition in females and males allowed to consume feed ad libitum. Forty mice were assigned within each sex (female [F] and male [M] to treatment of either 20 microL g-1 saline (Fs and Ms groups) or 74 ng rhGH g-1 body weight (BW) in 20 microL saline (FGH and MGH groups). At 50 d of age the mice were weighed and then killed by cervical dislocation. Treatment with rhGh improved feed conversion only in growing female mice by enhancing weight gain relative to feed protein intake and weight growth rate without modification of feed consumption, according to a multiple comparison test (LSD). Ms mice showed less carcass fat gain (162%), less fat accretion rate (129%), higher carcass water gain (12%) and higher water accretion rate (28%) than Fs mice. The administration of rhGH modified this distribution inducing an increase in gain and accretion rates of protein (34%), water (41%) and ash (33%) and a reduction in gain and accretion rate of fat (50%) in FGH mice, and only an increase of gain (91%) and accretion rate of fat (67%) in MGH mice compared to saline mice. As result, a decrease in protein gain:fat gain ratio of MGH mice compared to FGH (34%) and Ms (63%) mice was elicited by rhGH, inverting the inherent sexual propensity for fat and protein deposition in growing male mice, due to GH, sex, and to GH x sex interaction influence.

Muscle cell growth in protein deficient rats following administration of sheep red blood cells.

In order to observe the effects of sheep red blood cells (SRBC) administration on the muscle cell growth in malnourished states, adult male Wistar rats (135 +/- 10 g 10 animals per group) subjected during 30 days to 1% and 10% protein diets, were injected (i.v.) either 15.5 x 10(8) sheep red blood cells or 0.5 ml saline/100 g b.w. after 20 days of experiment. On the 10th day after injection the animals were sacrificed and the gastrocnemius muscle was removed, weighed and homogenized. The supernatant fluids were used to evaluate muscle protein, DNA and RNA rates and acid DNase activity. All parameters were depleted in malnourished rats, indicating a muscle cellular atrophy as well as a decrease in muscle protein synthesis per DNA-unit. Muscle hyperplasia and hypertrophy were found in antigenically stimulated rats fed 10% protein against non-stimulated control. In contrast, muscle growth in protein-deficient rats SRBC-treated was unmodified when compared to non-stimulated malnourished muscle, although RNA functionality seems to be enhanced (RNA/DNA). These data suggest that a redistribution of essential nutrients occurred for muscle growth adaptation rather than for defensive mechanism.