L-Arginine Supplementation Mitigates Dichlorvos-Induced Haematocardiotoxicity, and Oxidative Stress in Male Wistar Rats

Due to its toxicity, dichlorvos—a common organophosphate pesticide—poses significant risks to human health. This study utilized male Wistar rats to explore the potential protective effects of L-arginine supplementation against dichlorvos-induced toxicity, focusing on cardiotoxicity, haematotoxicity and oxidative stress. The rats were divided into four groups: Control, L-arginine (L), Dichlorvos (D), and L-arginine + Dichlorvos (L + D). Dichlorvos was administered to the D group, L-arginine (100 mg/kg) to the L group, and both L-arginine and dichlorvos to the L + D group. The study evaluated various parameters, including cardiovascular, oxidative stress markers, and haematological indices. Significant changes in haematological parameters such as haemoglobin (Hb), haematocrit (HCT), and red blood cell count (RBC) indicated haematotoxicity after dichlorvos administration. Additionally, elevated cardiac markers, including lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB), suggested cardiotoxic effects. Exposure to dichlorvos also resulted in decreased antioxidant enzyme levels and increased oxidative stress indicators like malondialdehyde (MDA). Remarkably, L-arginine supplementation mitigated the damage caused by dichlorvos. It normalized the altered haematological parameters, demonstrating its protective effect against haematotoxicity. The rise in cardiac markers was reduced with L-arginine supplementation, indicating protection against cardiotoxicity. Moreover, L-arginine significantly decreased oxidative stress, as evidenced by lower MDA levels and restored antioxidant enzyme activity. In conclusion, L-arginine supplementation in male Wistar rats showed promising protective effects against dichlorvos-induced cardiotoxicity, haematotoxicity and oxidative stress. This suggests that L-arginine may offer a beneficial intervention to mitigate the adverse effects of dichlorvos on blood and heart health, paving the way for potential treatments for pesticide poisoning.

L-Arginine及衰老对大鼠阴茎组织中NO、ET-1的影响

目的 探讨喂养左旋精氨酸 (L Arginine)及衰老对大鼠阴茎组织中“NO cGMP通路”及ET 1的影响及意义。方法 将不同月龄 ( 2、8、16、2 4月 )大鼠随机分为对照组与实验组 (喂养L Arginine) ,进行了以下研究 :①阴茎组织中一氧化氮(nitricoxide ,NO)、环磷酸鸟苷 (cGMP)含量测定 ;②阴茎组织一氧化氮合酶 (nitricoxidesynthase ,NOS)活性变化 ;③阴茎组织中ET 1(endothelin 1)含量测定。结果 ①阴茎组织中NO含量先升高后降低 ,8月龄最高 ,2 4月龄最低 ,NOS活性变化与其一致 ,各月龄组间差别均非常显著 (P <0 0 1) ;cGMP含量表现为显著降低 (P <0 0 1) ;ET 1含量呈升高趋势 ,ET 1/NO比值也显著升高 (P <0 0 1) ;②L Arginine长时间喂养大鼠后 ,阴茎组织中NOS活性及NO、cGMP含量均显著增加 (P <0 0 1) ,ET 1含量无明显改变。结论 阴茎组织中cGMP含量及ET 1/NO比值可能决定着平滑肌细胞舒缩状态 ;L Arginine对增强NOS活性、增加NO、cGMP含量有明显作用 ,表明L Arginine有用于治疗勃功能障碍 (erectiledysfunction ,ED)

BQ123与L-arginine在肝脏缺血再灌注损伤中的作用研究

目的 探讨肝脏缺血再灌注损伤的机制及 BQ12 3或 (和 ) L -arginine能否有效改善肝脏缺血再灌注损伤。方法 在大鼠肝脏缺血再灌注损伤模型基础上 ,对组织形态学、肝脏酶学、透明质酸、血浆内皮素及免疫组织化学染色情况进行观测。结果 肝脏缺血再灌注损伤时 ,血肝酶、透明质酶、血浆内皮素水平均显著增高 ,再灌注前使用 BQ12 3或 (和 ) L-arginine的肝脏 ,其组织结构及功能损伤均显著减轻。结论 肝脏缺血再灌注损伤与肝脏微循环改善有关 ,若能在肝脏再灌注前使用BQ12 3或 (和 ) L -arginine,可有效改善肝脏微循环 。

L-arginine对高糖诱导的内皮细胞衰老的作用

目的观察不同浓度的L-arginine对高糖诱导的人脐静脉内皮细胞（HUVECs）衰老的作用。方法HUVECs分别培养在正常糖浓度组（5．5mmol／L）、高糖组（33mmol／L）及高糖＋不同浓度L-arginine（0．4、0．8、1．6、3．2mmol／L）组，SAβ-gal活性评定细胞衰老的程度，PCR-ELISA法检测端粒酶活性，流式细胞术测定ROS及细胞周期，ELISA检测NO水平。结果与正常糖浓度组比较，高糖组SAβ-gal活性增强（P〈0．01），G0／G1期细胞比率增加（P〈0．01），端粒酶活性减弱（P〈0．01），细胞内ROS增多（P〈0．01），而NO水平减少（P〈0．001）。高糖环境下0．4—1．6mmol／L的L—arginine均可抑制SAβ—gal活性（P〈0．01），减少GD0/G0期细胞比率（P〈0．01），增强端粒酶活性（P〈0．01），减少细胞内ROS的生成（P〈0．01），增加NO水平（P〈0．01）。结论高糖可以诱导HUVECs的衰老。L-arginine可以延缓高糖诱导的内皮细胞衰老进程，但并没有明显的剂量依赖性。L—arginine可通过增强端粒酶活性，减少氧化应激，增加NO水平发挥抗内皮细胞衰老的作用。

L-arginine在高原鼠肝脏缺血再灌注损伤时肠道细菌易位中的作用研究

目的:探讨肝脏缺血再灌注损伤时肠道细菌易位的机制及精氨酸能否有效改善肠道细菌易位。方法:在大鼠肝脏缺血再灌注损伤模型基础上,对门静脉血、回肠系膜淋巴结进行肠道细菌培养。结果:肝脏缺血再灌注损伤时,血液及淋巴结可能培养出大肠埃希氏菌。但精氨酸预处理组与相同阻断时间组之间无差异。结论:高原地区第一肝门阻断的时间对肠道细菌易位有显著影响,但精氨酸对肝缺血再灌注损伤的肠道细菌易位无明显的保护作用。

氨基胍对内毒素活化小鼠巨噬细胞L-arginine转运及CAT-2表达影响的实验研究

目的:通过氨基胍(AG)干预内毒素活化小鼠巨噬细胞RAW264.7模型,观察NO的产生、左旋精氨酸(L-Arg)转运以及碱性氨基酸转运体-2(CAT-2)mRNA的表达,旨在研究氨基胍对L-Arg跨膜转运及CAT-2表达的影响。方法:实验分为四组,即对照组,LPS对照组,AG组,AG+LPS组。接种RAW264.7细胞于培养板后,37℃、5%CO2培养箱培养24 h,将AG组和AG+LPS组换以含AG 1 mmol/L的DMEM培养液,30 min后四组均换以新鲜DMEM培养液,其中LPS对照组和AG+LPS组加入LPS,继续培养18 h,检测细胞合成NO水平、L-Arg摄取率和CAT-2 mRNA表达。结果:与对照组比较,AG预处理后的RAW264.7细胞,经LPS活化后NO水平、L-Arg摄取率、CAT-2 mRNA水平显著降低。结论:AG作为一种特异的诱生型一氧化氮合酶(iNOS)抑制剂,不仅可抑制iNOS的活性,而且还可以从基因水平上抑制L-Arg转运体CAT-2的表达,进而阻断L-Arg的跨膜转运和NO合成。

Protective effects of L-arginine on reperfusion injury after pancreaticoduodenal transplantation in rats

BACKGROUND: Post-transplantation pancreatitis andgraft thrombosis are two major complications of pancreastrans-plantation that contribute to morbidity, mortality, andgraft loss. Nitric oxide (NO) is a potent vasodilator agentformed when L-arginine ( L-Arg) is converted to L-citrul-line by the action of NO synthase (NOS), and plays a ma-jor role in microcirculatory changes. We therefore investi-gated the effect of L-Arg on reperfusion injury followingpancreaticoduodenal transplantation in rats.METHODS: The homologous male Wistar rat model ofheterotopic total pancreaticoduodenal transplantation wasused. The L-Arg-treated rats received the intravenous in-jection of L-Arg 5 minutes before and after reperfusion at adose of 200 mg/kg while the N-Nitro-L-arginine methyl es-ter (L-NAME) -treated rats at a dose of 10 mg/kg. Theamount of NO in the pancreas graft was measured. Serumconcentration of cytokine-induced neutrophil chemoattrac-tant ( CINC) was determined by enzyme-linked immu-nosorbant assay, the expression of CINC mRNA was detect-ed by Northern blot assay in the pancreas graft, and the ac-tivity of myeloperoxidase (MPO) was measured. Histolo-gical examination was performed.RESULTS: The amount of NO was higher in the L-Arggroup than in the control group, while it was lower in theL-NAME group than in the control group (P <0.05). Thepeak of serum CINC concentration occurred 3 hours afterreperfusion with the difference among the groups being sig-nificant. The expression peak of CINC mRNA in the pan-creas graft occurred 3 hours after reperfusion. The expres-sion level in the L-Arg group (7.66 ± 1.53 μg/L) was lowerthan in the control group (26.31±2.01 μg/L), while in theL-NAME group (34.18 ±3.12 μg/L) it was higher than thatin the control group (P <0. 05). The activity of MPO inthe L-Arg group was obviously decreasd as compared within the other groups. The pancreas inflammation was ame-liorated when L-Arg was administered, whereas the panc-reas damage was aggravated when L-NAME was adminis-tered.CONCLUSIONS: L-Arg can increase the amount of NOand inhibit the elevation of CINC, the CINC mRNA ex-pression and early neutrophil accumulation in the pancreas.NO has protective effects on ischemia/reperfusion injury inpancreaticoduodenal transplantation.

Increased L-arginine Production by Site-directed Mutagenesis of N-acetyl-L-glutamate Kinase and pro B Gene Deletion in Corynebacterium crenatum

Objective In Corynebacterium crenatum,the adjacent D311 and D312 of N-acetyl-L-glutamate kinase(NAGK),as a key rate-limiting enzyme of L-arginine biosynthesis under substrate regulatory control by arginine,were initially replaced with two arginine residues to investigate the L-arginine feedback inhibition for NAGK.Methods NAGK enzyme expression was evaluated using a plasmid-based method.Homologous recombination was employed to eliminate the pro B.Results The IC50 and enzyme activity of NAGK M4,in which the D311 R and D312 R amino acid substitutions were combined with the previously reported E19 R and H26 E substitutions,were 3.7-fold and 14.6% higher,respectively,than those of the wild-type NAGK.NAGK M4 was successfully introduced into the C.crenatum MT genome without any genetic markers;the L-arginine yield of C.crenatum MT-M4 was 26.2% higher than that of C.crenatum MT.To further improve upon the L-arginine yield,we constructed the mutant C.crenatum MT-M4 ?pro B.The optimum concentration of L-proline was also investigated in order to determine its contribution to L-arginine yield.After L-proline was added to the medium at 10 mmol/L,the L-arginine yield reached 16.5 g/L after 108 h of shake-flask fermentation,approximately 70.1% higher than the yield attained using C.crenatum MT.Conclusion Feedback inhibition of L-arginine on NAGK in C.crenatum is clearly alleviated by the M4 mutation of NAGK,and deletion of the pro B in C.crenatum from MT to M4 results in a significant increase in arginine production.

Competitive metabolism of L-arginine:arginase as a therapeutic target in asthma

Exhaled breath nitric oxide （NO） is an accepted asthma biomarker. Lung concentrations of NO and its amino acid precursor, L-arginine, are regulated by the relative expressions of the NO synthase （NOS） and arginase isoforms. Increased expression of arginase I and NOS2 occurs in murine models of allergic asthma and in biopsies of asthmatic airways. Although clinical trials involving the inhibition of NO-producing enzymes have shown mixed results, small molecule arginase inhibitors have shown potential as a therapeutic intervention in animal and cell culture models. Their transition to clinical trials is hampered by concerns regarding their safety and potential tox- icity. In this review, we discuss the paradigm of arginase and NOS competition for their substrate L-arginine in the asthmatic airway. We address the functional role of L-arginine in inflammation and the potential role of arginase inhibitors as therapeutics.

Effect of Sodium Alginate Concentration on Membrane Strength and Permeating Property of Poly-l-arginine Group Microcapsule

A novel poly-/-arginine microcapsule was prepared due to its nutritional function and pharmacological efficacy. A high-voltage electrostatic droplet generator was used to make uniform microcapsules. The results show that the membrane strength and permeating property are both remarkably affected with the changes of sodium alginate concentration. With the sodium alginate concentration increasing, gel beads sizes increase from 233μm to 350μm, release ratio is also higher at the same time, but the membrane strength decreases.

Protective effects of L-arginine against ischemia-reperfusion injury in non-heart beating rat liver graft

BACKGROUND: Although the use of non-heart beating donors (NHBDs) could bridge the widening gap between organ demand and supply, its application to liver transplantation is limited due to the high incidence of primary graft loss. Prevention of liver injury in NHBDs will benefit the results of transplantation. This study was conducted to evaluate the protective effects of L-arginine on liver grafts from NHBDs. METHODS: One hundred and four Wistar rats were randomly divided into 7 groups: normal control (n=8) controls 1, 2 and 3 (C-1, C-2, C-3, n=16), and experimental 1, 2 and 3 (E-1, E-2, E-3, n=16). For groups C-1 and E-1, C-2 and E-2, and C-3 and E-3, the warm ischemia time was 0, 30, and 45 minutes, respectively. Liver grafts were flushed with and preserved in 4 degrees C Euro-collins solution containing 1 mmol/L L-arginine for 1 hour in each experimental group. Recipients of each experimental group were injected with L-arginine (10 mg/kg body weight) by tail vein 10 minutes before portal vein reperfusion. Donors and recipients of each experimental control group were treated with normal saline. Then transplantation was performed. At 1, 3, and 24 hours after portal vein reperfusion, blood samples were obtained to determine the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), nitric oxide (NO) and plasma endothelin (ET). At 3 hours after portal vein reperfusion, grafts samples were fixed in 2.5% glutaraldehyde for electron microscopic observation. RESULTS: At I hour after portal vein reperfusion, the levels of NO in groups E-1, E-2, E-3 and C-1, C-2, C-3 were lower, while the levels of plasma ET, serum ALT and AST were higher than those in the normal control group (P<0.05). At 1, 3, and 24 hours, the levels of NO in groups E-1, E-2, E-3 were higher, while the levels of plasma ET, serum ALT and AST were lower than those in the corresponding control groups (C-1, C-2, C-3) (P<0.05). The levels of NO in groups C-2 and C-3 were lower than in group C-1 (P<0.05), and the level of NO in group C-3 was lower than in group C-2 (P<0.05). At 1, 3 and 24 hours, the levels of plasma ET, serum ALT, and AST in groups E-1, E-2, E-3 were lower than those in the corresponding control groups (C-1, C-2, C-3) (P<0.05). The levels of plasma ET, serum ALT, and AST were lower in group C-3 than in groups C-1 and C-2 (P<0.05). Pathological changes in groups E-1, E-2, E-3 were milder than those in the corresponding experimental control groups (C-1, C-2, C-3). CONCLUSIONS: The imbalance between NO and ET plays an important role in the development of ischemia-reperfusion injury of liver grafts from NHBDs. L-arginine can attenuate injury in liver grafts from NHBDs by improving the balance between NO and ET.

Celecoxib-induced gastrointestinal, liver and brain lesions in rats, counteraction by BPC 157 or L-arginine, aggravation by L-NAME

To counteract/reveal celecoxib-induced toxicity and NO system involvement. METHODSCelecoxib (1 g/kg b.w. ip) was combined with therapy with stable gastric pentadecapeptide BPC 157 (known to inhibit these lesions, 10 μg/kg, 10 ng/kg, or 1 ng/kg ip) and L-arginine (100 mg/kg ip), as well as NOS blockade [N(G)-nitro-L-arginine methyl ester (L-NAME)] (5 mg/kg ip) given alone and/or combined immediately after celecoxib. Gastrointestinal, liver, and brain lesions and liver enzyme serum values in rats were assessed at 24 h and 48 h thereafter. RESULTSThis high-dose celecoxib administration, as a result of NO system dysfunction, led to gastric, liver, and brain lesions and increased liver enzyme serum values. The L-NAME-induced aggravation of the lesions was notable for gastric lesions, while in liver and brain lesions the beneficial effect of L-arginine was blunted. L-arginine counteracted gastric, liver and brain lesions. These findings support the NO system mechanism(s), both NO system agonization (L-arginine) and NO system antagonization (L-NAME), that on the whole are behind all of these COX phenomena. An even more complete antagonization was identified with BPC 157 (at both 24 h and 48 h). A beneficial effect was evident on all the increasingly negative effects of celecoxib and L-NAME application and in all the BPC 157 groups (L-arginine + BPC 157; L-NAME + BPC 157; L-NAME + L-arginine + BPC 157). Thus, these findings demonstrated that BPC 157 may equally counteract both COX-2 inhibition (counteracting the noxious effects of celecoxib on all lesions) and additional NOS blockade (equally counteracting the noxious effects of celecoxib + L-NAME). CONCLUSIONBPC 157 and L-arginine alleviate gastrointestinal, liver and brain lesions, redressing NSAIDs’ post-surgery application and NO system involvement.

α,β-amyrin, a natural triterpenoid ameliorates L-arginine-induced acute pancreatitis in rats

AIM: To study the benef icial effects of triterpene α,β-amyrin and the underlying mechanisms in an experimental pancreatitis model. METHODS: Acute pancreatitis was induced in five groups of rats (n = 8) by L-arginine (2 × 2.5 g/kg, intraperitoneal, 1 h apart) and 1 h later, they received a single oral dose of α,β-amyrin (10, 30 and 100 mg/kg),methylprednisolone (30 mg/kg) and vehicle (3% Tween 80). A saline (0.9% NaCl) treated group served as a normal control. Efficacy was assessed at 24 h by determination of serum levels of amylase, lipase and proinflammatory cytokines [tumor necrosis factor (TNF)-α and interleukin (IL)-6], pancreatic myeloperoxidase (MPO) activity, lipid peroxidation [thiobarbituric acid reactive substances (TBARS)], nitrate/nitrite levels, and the wet weight/body weight ratio. Tissue histology and the immunoreactivity for TNF-α and inducible nitric oxide synthetase (iNOS) were performed. RESULTS: α,β-amyrin and methylprednisolone treatments significantly (P < 0.05) attenuated the L-arginine-induced increases in pancreatic wet weight/body weight ratio, and decreased the serum levels of amylase and lipase, and TNF-α and IL-6, as compared to the vehicle control. Also, pancreatic levels of MPO activity, TBARS, and nitrate/nitrite were signifi cantly lower. Histological f indings and TNF-α and iNOS immunostaining further confirmed the amelioration of pancreatic injury by α,β-amyrin. CONCLUSION: α,β-amyrin has the potential to combat acute pancreatitis by acting as an anti-in? ammatory and antioxidant agent.

Counteraction of perforated cecum lesions in rats: Effects of pentadecapeptide BPC 157,L-NAME and L-arginine

AIM To study the counteraction of perforated cecum lesion using BPC 157 and nitric oxide(NO) system agents.METHODS Alongside with the agents' application(after 1 min, medication(/kg, 10 ml/2 min bath/rat) includes: BPC 157(10 μg), L-NAME(5 mg), L-arginine(100mg) alone or combined, and saline baths(controls)) on the rat perforate cecum injury, we continuously assessed the gross reappearance of the vessels(USB microcamera) quickly propagating toward the defect at the cecum surface, defect contraction, bleeding attenuation, MDA-and NO-levels in cecum tissue at 15 min, and severity of cecum lesions and adhesions at 1 and 7 d. RESULTS Post-injury, during/after a saline bath, the number of vessels was significantly reduced, the defect was slightly narrowed, bleeding was significant and MDA-levels increased and NO-levels decreased. BPC 157 bath: the vessel presentation was markedly increased, the defect was noticeably narrowed, the bleeding time was shortened and MDA-and NO-levels remained normal. L-NAME: reduced vessel presentation but not more than the control, did not change defect and shortened bleeding. L-arginine: exhibited less vessel reduction, did not change the defect and prolonged bleeding. In combination, mutual counteraction occurred(L-NAME + L-arginine) or the presentation was similar to that of BPC 157 rats(BPC 157 + L-NAME; BPC 157 + L-arginine; BPC 157 + L-NAME + L-arginine), except the defect did not change. Thereby at day 1 and 7, saline, L-NAME, L-arginine and L-NAME + L-arginine failed(defect was still open and large adhesions present). CONCLUSION The therapeutic effect was achieved with BPC 157 alone or in combination with L-NAME and L-arginine as it was able to consolidate the stimulating and inhibiting effects of the NO-system towards more effective healing recruiting vessels.

L-Arginine Modulates Maternal Hormonal Profiles and Neonatal Traits during Two Stages of Pregnancy in Sheep

A 2 × 2 factorial arrangement was designed to test effects of supplementation of a low (L, 75 mg/kg BW) vs. high (H, 150 mg/kg BW) L-arginine given at early (first 56 days) vs. late (last 56 days) pregnancy on maternal hormones and neonatal traits. Thirty Najdi pregnant ewes were randomly allocated into 6 groups. Ewes in G1 and G2 served as controls (C), given 50 ml saline at either early (CE) or late (CL) pregnancy, respectively. G3 and G4 ewes in early pregnancy received low (LE) and high L-arginine (HE), respectively. G5 and G6 ewes in late pregnancy received low (LL) and high (HL) L-arginine, respectively. A weekly blood sample was collected from initiation of the treatment till parturition. Serum growth hormone (GH), insulin-like growth factor-I (IGF-I), insulin, progesterone (P4) and estradiol 17 β (E2) profiles were determined. Neonatal traits were also determined. Insulin was higher (P 0.05). Lamb survival rates at birth in LE ewes were highest (100%) compared to other treatments. In conclusion, supplementing pregnant ewes with low dosage of L-arginine at early stage of gestation increased lamb birth weight and survival, and improved maternal health.

Bypassing major venous occlusion and duodenal lesions in rats, and therapy with the stable gastric pentadecapeptide BPC 157, L-NAME and L-arginine

AIM To investigate whether duodenal lesions induced by major venous occlusions can be attenuated by BPC 157 regardless nitric oxide(NO) system involvement.METHODS Male Wistar rats underwent superior anterior pancreaticoduodenal vein(SAPDV)-ligation and were treated with a bath at the ligated SAPDV site(BPC 157 10 μg, 10 ng/kg per 1 mL bath/rat; L-NAME 5 mg/kg per 1 m L bath/rat; L-arginine 100 mg/kg per 1 mL bath/rat, alone and/or together; or BPC 157 10 μg/kg instilled into the rat stomach, at 1 min ligation-time). We recorded the vessel presentation(filled/appearance or emptied/disappearance) between the 5 arcade vessels arising from the SAPDV on the ventral duodenum side, the inferior anterior pancreaticoduodenal vein(IAPDV) and superior mesenteric vein(SMV) as bypassing vascular pathway to document the duodenal lesions presentation; increased NO-and oxidative stress [malondialdehyde(MDA)]-levels in duodenum.RESULTS Unlike the severe course in the SAPDV-ligated controls, after BPC 157 application, the rats exhibited strong attenuation of the mucosal lesions and serosal congestion, improved vessel presentation, increased interconnections, increased branching by more than 60% from the initial value, the IAPDV and SMV were not congested. Interestingly, after 5 min and 30 min of L-NAME and L-arginine treatment alone, decreased mucosal and serosal duodenal lesions were observed; their effect was worsened at 24 h, and no effect on the collateral vessels and branching was seen. Together, L-NAME+L-arginine antagonized each other's response, and thus, there was an NO-related effect. With BPC 157, all SAPDV-ligated rats receiving L-NAME and/or L-arginine appeared similar to the rats treated with BPC 157 alone. Also, BPC 157 in SAPDV-ligated rats normalized levels of NO and MDA, two oxidative stress markers, in duodenal tissues.CONCLUSION BPC 157, rapidly bypassing occlusion, rescued the original duodenal flow through IAPDV to SMV flow, aneffect related to the NO system and reduction of free radical formation.

Influence of L-arginine on the Expression of eNOS and COX2 in Experimental Pulmonary Thromboembolism

The influence of L-arginine on endothelial nitric oxide synthase （eNOS） and cyclooxygenase 2 （COX2） was observed in experimental pulmonary thromboembolism and the action mechanism on pulmonary thromboembolism was explored. Wistar rats were randomly divided into control group, model group and treatment group. Pulmonary thromboembolism models were established by auto-blood back transfusion, and L-Arg 100 mg/kg was intraperitoneally injected after successful model preparation. The animals were sacrificed at 3 h, 1 day, 3 days and 7 days after embolism. Plasma NO, TXB2 and 6-Keto-PGF1 α were detected. The expression of eNOS and COX2 protein and mRNA in pulmonary tissues was detected by immunohistochemistry and RT-PCR respectively. The results showed that pulmonary thrombosis could be seen post pulmonary embolism and inflammatory reaction was significant. Plasma NO was decreased （P〈0.01）, and the levels of TXB2, 6-Keto-PGF1α and T/P ratio were all elevated. The expression of eNOS protein and mRNA in the pulmonary tissue was down-regulated （P〈0.05）, while that of COX2 protein and mRNA was upregulated （P〈0.01）. In treatment group, the level of NO was increased, the levels of TXB2 and T/P ratio were decreased, but the level of 6-Keto-PGF1 α was increased. The expression of eNOS protein and mRNA in pulmonary tissue was upregulated （P〈0.05）, while that of COX2 protein and mRNA was down-regulated （P〈0.05）. In conclusion, L-arginine can educe the role of pulmonary tissue protection through up-regulating the expression of intra-pulmonary NOS and down -regulating COX2 in pulmonary thromboembolism.

Heterotactic Enthalpic Interactions of L-Arginine with 2,2,2-Trifluoroethanol in Aqueous Solutions at 298.15, 303.15 and 310.15 K

The enthalpies of mixing of L-arginine with 2,2,2-trifluoroethanol and their respective enthalpies of dilu- tion in aqueous solutions at 298.15, 303.15 and 310.15 K were determined as a function of the mole fraction by flow microcalorimetric measurement. These experimental results were analyzed to obtain heterotactic enthalpic interaction coeffieients（hxy , hxy , hxy） according to the McMillan-Mayer theory. The hxy coefficients between L-arginine molecule studied and 2,2,2-trifluoroethanol molecule in aqueous solutions at 298.15, 303.15 and 310.15 K were found to be all negative. The results were discussed in terms of solute-solute interaction and solute-solvent interaction.

L-arginine, the substrate of nitric oxide synthase,inhibits fertility of male rats

Aim: To examine the effect of L-arginine, the substrate of nitric oxide (NO) synthase, on reproductive function ofmale rats. Methods: Male rats were gavaged with either L-arginine (100 or 200 mg·kg^(-1)·d^(-1)), D-arginine (200mg·kg^(-1)·d^(-1)) or vehicle (0.9% NaCl) for seven consecutive days. Their sexual behaviour and fertility were evaluat-ed using receptive females. Results: L-arginine (200 mg/kg) had no significant effect on sexual competence (interms of sexual arousal, libido, sexual vigour and sexual performance). In mating experiments, the higher dose of L-arginine effectively and reversibly inhibited fertility, whilst the lower dose and the inactive stereoisomer D-arginine hadno significant effect. The antifertility effect caused by L-arginine was due to a profound elevation in the preimplantationloss mediated possibly by impairment in epididymal sperm maturation, hyperactivated sperm motility and sperm capaci-tation. Conclusion: Elevated NO production may be detrimental to male fertility.

Kidney response to L-arginine treatment of carbon tetrachloride-induced hepatic injury in mice

Hepatic injury can be induced by the administration of carbon tetrachloride (CCl4) via the production of free radicals. The present work was initiated to investigate the kidney response to hepatic injury induced by CCl4 and its treatment by L-arginine. Female Swiss albino mice were supplied with L-arginine for 6 days (orally, 200 mg/kg body weight) prior or post to hepatic injury induction through i.p. injection with a single dose of CCl4 (20 mg/kg body weight) for 24 h. After hepatic injury induction, renal MDA content was significantly elevated while renal GSH level and the activities of antioxidant enzymes (GR, GPx, GST, catalase, and SOD) were significantly decreased. These results suggest that CCl4 not only induces hepatic injury but also induces kidney dysfunction side by side. Following the treatment with L-arginine, all levels were almost back to normal. Therefore, Larginine administration is found to be an effective protector of both liver and kidney against CCl4-intoxication.