Effects Of L-arginine Treatment Research Articles

Effect of l-Arginine treatment on the in vitro stability of electrospun aligned chitosan nanofiber mats

Chitosan (Cs) mats obtained by electrospinning are potentially ideal scaffolds for tissue engineering. This technique allows obtaining nanometric fibrous structures with preferred orientation, which in turn enable cells to align themselves and produce extracellular matrix along desired orientations. In this study, we fabricated aligned Cs electrospun nanofiber mats and investigated the role of the amino acid l-Arginine (L-Arg) as stabilizing agent. Morphological, chemical, mechanical and biological characterizations were performed on untreated and L-Arg treated nanofibrous mats showing the role of L-Arg as biomimetic stabilizer. L-Arg acts as chemical stabilizer of nanofibrous mats, providing improved wettability behavior, mechanical properties and stability even after 60 days in aqueous medium in comparison to untreated mats. Moreover, preliminary biological tests demonstrated favorable cell-material interactions implying physiological responses in terms of viability and proliferation. The proposed L-Arg-treated Cs mats can be considered as potential scaffolds for highly oriented tissue patterning.

Effect of L-arginine treatment on motility, hyperactivity, acrosome reaction of ejaculated ram spermatozoa

The aim of this study was to evaluate the effect of in vitro treatment of ejaculated ram spermatozoa with different concentrations of L-arginine at various incubation times on motility, hyperactivity (HA) and acrosome reaction. Freshly ejaculated spermatozoa collected from three rams were pooled and subjected to the swim up technique in modified sperm Tyrode's albumin lactate pyruvate (S-TALP) medium supplemented with different concentrations of Larginine (0.01, 0.02, 0.03,0.04 and 0.05 mM) at 30, 60,90 and 120 min of incubation. Following sperm incubation, the following parameters were examined: motility, hyperactivity (HA) and acrosome reaction (AR). The results showed that irrespective of the concentration, incubation of ram spermatozoa with Larginine for 30min did not significantly affect the motility. However, increase the time of incubation for more than 30 min significantly decreased (P < 0.05) the motility of the spermatozoa as compared to the control. The lowest motility was recorded when spermatozoa were incubated with 0.05 mM L-arginine for 120 min. Treatment of ram spermatozoa with 0.05 mM Larginine resulted in a significant (P < 0.05) increase in HA% immediately after dilution compared to the control. A significant (P < 0.05) increase in total AR% was concomitant to the increase in the concentration of L-arginine with highest AR achieved at 0.04 mM and 90 min incubation. However, increasing the time of incubation to 120 min significantly decreased (P < 0.05) the percentage of spermatozoa with total AR compared to the other incubation times at 0.02, 0.04, and 0.05 mM L-arginine. In conclusion, under our experimental conditions treatment of ejaculated ram spermatozoa with 0.04 mM of L-arginine for 90 min was considered the best concentration of L-arginine to be used for in vitro induction of acrosome reaction.

L-Arginine in pregnant scleroderma patients

Systemic sclerosis (SSc) pregnant women show a high frequency of premature births and occurrence of renal crisis. Some evidences showed the role of L-arginine in the prevention and treatment of preeclampsia. Here, we report our experience on the effect of L-arginine treatment in four consecutive SSc pregnant women. Two patients, who have planned the pregnancy, were treated with oral L-arginine; both delivered healthy babies without any prenatal complications. The other two, with high risk of pregnancy complications because of severe lung involvement and type 1 diabetes, respectively, underwent i.v. L-arginine: patient 3 had a premature delivery of a 2-kg healthy baby, while patient 4 developed preeclampsia and, at the 28th week, delivered a 1,050-g girl. The neonate had severe respiratory distress syndrome complicated by severe infection and died at day 28. Although limited, our pilot study suggests that L-arginine may be a useful therapeutic agent in pregnant SSc women.

Potential adverse effect of L-arginine treatment on outcome after hypovolemic traumatic shock

Potential adverse effect of L-arginine treatment on outcome after hypovolemic traumatic shock

L-Arginine treatment may prevent tubulointerstitial nephropathy caused by germanium dioxide

Long-term oral ingestion of germanium dioxide (GeO2) causes progressive renal failure derived from tubulointerstitial nephropathy in humans and animals. The characteristic of GeO2-induced nephropathy is the renal tissue injury persisting for a long time, even after cessation of GeO2 ingestion. However, a treatment that can suppress the long-lasting renal tissue injury has not yet been established. Using the methods of immunohistochemistry and reverse transcription-polymerase chain reaction, we examined the expression of ED1-positive cells (macrophages/monocytes), transforming growth factor (TGF)-beta1 mRNA and protein and collagen type IV mRNA and protein in the kidneys of rats with GeO2-induced nephropathy. Concomitantly, the effects of L-arginine treatment on their expression was explored in the kidneys of rats with GeO2-induced nephropathy. Chronic administration of GeO2 caused tubulointerstitial nephropathy characterized by leukocyte invasion into the enlarged tubulointerstitial space in rats. The expression of ED1-positive cells, TGF-beta1 protein and collagen type IV protein was markedly increased in the tubulointerstitium of the renal cortex from rats with GeO2-induced nephropathy. Similarly, TGF-beta1 and collagen type IV mRNA were significantly enhanced in the renal cortex of rats with GeO2-induced nephropathy. A small number of tubulointerstitial cells expressing TGF-beta1 protein were also observed in the renal cortex of rats with GeO2-induced nephropathy. However, L-arginine treatment led to a parallel decrease in the expression of ED1-positive cells, TGF-beta1 mRNA and collagen type IV mRNA and protein in rats with GeO2-induced nephropathy. In general, collagen synthesis is driven by TGF-beta1 in the fibrotic process associated with a variety of renal disorders. TGF-beta1 is secreted by TGF-beta1 producing cells such as macrophages, fibroblasts and myofibroblasts. Thus, the present study indicates that the expression of collagen type IV may be mediated by TGF-beta1 released from invading macrophages and, to a lesser extent, released from tubulointerstitial cells, presumably fibroblasts and/or myofibroblasts in GeO2-induced nephropathy. L-Arginine treatment inhibits collagen type IV synthesis possibly by suppressing macrophage invasion and the resultant TGF-beta1 expression in this nephropathy. L-Arginine treatment may be beneficial in the prevention of tubulointerstitial fibrosis, which is considered to be the terminal stage of GeO2-induced nephropathy.

Effects of l-arginine treatment on symptoms and bladder nitric oxide levels in patients with interstitial cystitis

Objectives. Nitric oxide (NO) is involved in host defense reactions, and NO production is elevated in various inflammatory disorders. We have found very high levels of luminal NO in the urinary bladder of patients with interstitial cystitis. Oral treatment with low doses of l-arginine, the substrate for NO production, has been reported to alleviate symptoms in patients with interstitial cystitis. The aim of our investigation was to evaluate the effect of higher doses of l-arginine in patients with interstitial cystitis and to study the effects of l-arginine on NO production in the bladder. Methods. Nine women (age 69 ± 3 years) with interstitial cystitis were treated daily with 3 or 10 g of l-arginine for 5 weeks. Symptoms were evaluated with an interstitial cystitis symptom score index, and NO production was measured. Patients with stress incontinence (n = 18) were used as control subjects for measurement of NO levels. Results. NO concentration in the urinary bladder was markedly elevated in the patients with interstitial cystitis (239 ± 60 ppb) compared with the control patients (15 ± 2 ppb). NO levels did not change in the patients with interstitial cystitis after oral treatment with l-arginine (189 ± 72 ppb). There was no significant change in the symptom scores at either dose after 5 weeks of l-arginine treatment. Conclusions. l-arginine treatment in the doses used in this study did not change NO production in the urinary bladder in patients with interstitial cystitis. Furthermore, the patients in our study did not notice any relief of their symptoms.

Dexamethasone-induced hypertension in the rat: effects of L-arginine.

1. The effects of L-arginine treatment on dexamethasone-induced hypertension were examined in the Sprague-Dawley rat. Seventy rats were randomly divided into the following eight groups: sham, dexamethasone (5 and 10 micrograms/day, L-arginine (100 and 500 mg/kg per day), L-arginine (100 or 500 mg/kg per day) + dexamethasone (10 micrograms/day), L-arginine (520-797 mg/kg per day in food) + dexamethasone (5 micrograms/day). Systolic blood pressure (SBP), bodyweight and plasma nitrate/nitrite concentration were measured. 2. Dexamethasone (5 and 10 micrograms/day) increased SBP in both sham and L-arginine-treated rats. Dexamethasone at 10 micrograms/day decreased bodyweight, but did not alter plasma nitrate/nitrite concentrations. 3. L-Arginine (500 mg/kg per day, i.p.) increased plasma nitrate/nitrite concentrations in 10 micrograms/day dexamethasone-treated rats. L-Arginine did not alter blood pressure in either sham or dexamethasone-treated rats. 4. Dexamethasone-induced hypertension differs from adrenocorticotropic hormone (ACTH)-induced hypertension in the rat in that it is not modified by L-arginine. Thus, ACTH-induced hypertension cannot be explained simply in terms of glucocorticoid activity.

Effect of L-Arginine Treatment in Pregnant Rats with Adriamycin Nephropathy

Objective: The influence of pregnancy (P) on the evolution of primary renal disease is still controversial. In rats with early adriamycin nephropathy (ADR), pregnancy enhanced mean arterial pressure (MAP) and urine protein excretion (UP). It has been suggested that the development of hypertension in pregnancy may be related to a decreased synthesis of vasodilatory substance(s) by endothelial cells. In the present study, the effect of L-arginine, a precursor of the endothelium-derived relaxing factor nitric oxide (NO), was evaluated.Methods: Four groups of rats were studied (n = 10 each): 1—normal pregnancy (NP); 2-normal pregnancy treated with L-arginine (NP + LA); 3-ADR pregnant rats (ADRP); and 4-ADR pregnant rats treated with L-arginine (ADRP-1-LA). L-arginine, 2 g/1, was added to the drinking water from midpregnancy.Results: In ADRP rats, MAP increased to 135 ± 4.1 mm Hg, significantly above the values of 91 ± 1.2 mm Hg found in NP rats, P <. 01. Treatment with L-arginine did not influence MAP in NP +...