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BACKGROUND: Studies have shown that nitric oxide(NO) can effectively improve blood supply and promote flap survival, but the specific mechanism is still unclear. OBJECTIVE: To explore the effects of L-arginine(L-Arg) on the survival of extended dorsal perforator skin flap in rats by activating L-Arg-NO pathway. METHODS: Animal models of extended dorsal perforator skin flap were successfully established in 81 male Sprague Dawley rats, which were then divided into a L-Arg group, a blank group and a L-NAME group. L-Arg(400 mg/kg per day) and nitro-amino-methyl-L-arginine(L-NAME; 40 mg/kg per day) were injected intraperitoneally in the L-Arg group and L-NAME group immediately and 1-7 days after operation, respectively, while the same volume of isotonic sodium chloride solution was injected intraperitoneally in the blank group at the same time points. Flap survival rate was measured. Angiography was performed to observe appearance and distribution of blood vessels at 7 days after operation. NO concentration of choke II zone was detected immediately, 1, 3, 5, and 7 days after operation. Tissue samples were harvested from the choke II zone for detecting density and caliber of new blood vessels using hematoxylin-eosin staining and the expression of vascular endothelial growth factor and matrix metalloproteinase was detected by western blot, respectively. The study protocol was approved by the Animal Ethics Committee of the 94 th Hospital of the PLA Joint Logistics Support Force(approval No. 2015 KYLL046). RESULTS AND CONCLUSION: The highest survival rate of flap appeared in the L-Arg group, (89.47±3.17)%, which was significantly higher than that in the other groups(F=49.908, P < 0.001). At 7 days after operation, the vascular structure in the choke II zone of the L-Arg group was relatively complete with clear trajectory. The vessels that had expanded to achieve true anastomosis extended along the longitudinal axis of the flap to the end of the flap. In the blank group and L-NAME group, the vascular structure and vascular trajectory in the choke II zone were disordered. Moreover, the vascular structure at the end of flap in L-NAME group disappeared. NO concentration in L-Arg group was increased after surgery, peaked at 3 days after operation, and then decreased gradually. Microvessel density and caliber in the L-Arg group were significantly higher than those in the other groups at 7 days after operation(P < 0.001). Western blot showed that the expression of vascular endothelial growth factor and matrix metalloproteinase-2 were significantly higher in the L-Arg group than the other groups at 3 after operation(P < 0.05), while at 7 days after operation, the expression of vascular endothelial growth factor in the L-Arg group was significantly higher than that in the other groups(P < 0.05), but the expression of matrix metalloproteinase-2 showed no significant difference among the three groups. To conclude, NO could promote microvascular growth and dilatation in the choke II zone of extended dorsal three-vascular perforator flaps in rats; L-Arg could increase the NO concentration in tissue by activating the L-Arg-NO pathway, which is beneficial to the survival of skin flap.
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OBJECTIVE: To observe the effect of electroacupuncture (EA) on changes of expression of L-Arg transporter 2 (CAT-2) mRNA and nitric oxide synthase (iNOS) mRNA and protein and contents of NO and cGMP of L4-L6 segments of spinal cord in rats with spared nerve injury (SNI), so as to reveal its mechanism underlying reducing neuropathic pain. METHODS: A total of 120 male SD rats were randomly divided into sham operation, model, EA and NOS inhibitor (N omega-Nitro-L-arginine methyl ester hydrochloride, L-NAME) groups, with 30 rats in each group. The neuropathic pain model was established by ligating and cutting the tibial nerve and the common peroneal nerve. EA (2 Hz, 1-3 mA) was applied to "Weizhong" (BL40) and "Huantiao" (GB30)on the damaged hindlimb for 30 min, once daily from day 11 to 17 after SNI. Rats of the L-NAME group received i.p. of L-NAME (60 mg·kg-1·d-1) for 7 consecutive days. The mechanical pain threshold (PT) was determined before and 10 and 16 d after SNI, respectively. The expression le-vels of CAT-2 mRNA and iNOS mRNA, and iNOS protein in the L4-L6 segments of the spinal cord were detected by using reverse transcription - polymerase chain reaction (RT-PCR) and Western blot, respectively, and the contents of NO and cGMP of L4-L6 assayed using nitrate/nitrite reductase method and radioimmunoassay, respectively. RESULTS: After modeling, the PT was significantly decreased on day 10 and 16 after SNI in comparison with the sham operation group and their own baseline data of pre-operation in each group (P0.05). CONCLUSION: EA intervention can effectively relieve neuropathic pain in SNI rats, which may be closely related to its function in suppressing L-Arg/NO/cGMP pathway in the lumbar spinal cord.
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AIM:To investigate the antidepressant effect of dextromethorphan(DXM)and its mechanism. METHODS:The antidepressant effect of DXM was observed by the methods of forced swimming test,tail suspension test and open field test.The N-methyl-D-aspartate(NMDA)receptor activity in brain,and the effects of total nitric oxide syn-thases(NOS)and various types of NOS were examined by molecular biology methods.The mice pretreated with NMDA re-ceptor antagonist MK-801(MK),NMDA,NO precursor L-arginine(L-ARG),endothelial NOS(eNOS)inhibitor Nω-ni-tro-L-arginine methyl ester(L-NAME),inducible NOS(iNOS)inhibitor aminoguanidine(AG),neuronal NOS(nNOS) inhibitor 7-nitroindole(7-NI)or phosphodiesterase 5 inhibitor sildenafil were given DXM to explore the mechanism of DXM as an antidepressant.RESULTS: DXM had a dose-dependent antidepressant effect.DXM inhibited the activity of brain NMDA receptor in a dose-dependent manner, and inhibited the expression of eNOS and nNOS.MK, L-NAME and 7-NI were able to promote the antidepressant effect of DXM.NMDA,L-ARG and sildenafil were able to inhibit the antidepres-sant effect of DXM.AG did not influence the antidepressant effect of DXM.CONCLUSION:DXM has an antidepressant effect,and NMDA receptor and L-ARG-NO-cGMP signaling pathways are involved in this process.
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Objective: To explore the effects of Yueju pill on Nitricoxide-cyclic guanosine monophosphate (NO-cGMP) signaling in mouse hippocampus. Methods: Single dose of Yueju pill was administered, and mouse hippocampi were got out after administration for 12 min, 24 min, 30 min, 3 h and 24 h. The concentrations of NO and cGMP were detected by ELISA. Other mice were randomly divided into the following groups: control group (con), L-arg group (L-arg), Yueju pill group (YJ) and L-arg+ Yueju pill group (L-arg+YJ) . Control group was treated with saline, YJ group was treated with Yueju pill (13.5 g·kg-1), and L-arg group was treated with L-arg (750 mg·kg-1) . Tail suspension test (TST) was measured30 min after administration.Results:12 min after YJ administration, the concentration of NO was significantly lower than that in control group (P ＜ 0.05) and the concentration of c GMP was also significantly lower than that in control group (P ＜ 0.05) . In the TST test, the immobility time in YJ group was significantly shorter than that in control group (P ＜ 0.01), and the immobility time in L-arg+YJ group was significantly longer than that in YJ group (P ＜ 0.01) . In open field test (OFT), the spontaneous activity of mice were not affected by administering L-arg or YJ. Conclusion: Yueju pill may rapidly alleviate depression-like behaviors of mice through regulating NO concentration, then influencing downstream cGMP and activating the NO-cGMP signaling in cells.
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Objective: To observe the L-Arg (L-arginine) transport, the nitric oxide (NO) production, and NO synthase (NOS) activity in platelets, investigate the significance of the L-Arg-NO system in the pathogenesis of microvascular angina (MVA), and to study the reversing effects of intravenous L-Arg infusion on L-Arg transport. Methods: The 3H-L-Arg transport, NO production, and NOS activity in platelets were examined in 15 patients with MVA and 15 healthy controls. The 15 patients were given intravenous L-Arg infusion (20 g/d) after basic physical examination and were examined again 10 days later. Results: The L-Arg transport in platelets of MVA patients was obviously lower than that in the normal group; the maximum transport velocity (Vmax) decreased by 34. 4% compared with the normal group (P<0.01); and the Michaelis constant (Km) increased by 21.4% (P<0.05). The production of NO2- and the activity of NOS in platelets were decreased by 47.1% (P< 0.05) and 25.4% (P<0.05) compared with the normal group, respectively. Intravenous L-Arg infusion reversed the above changes in MVA patients; it increased the Vmax by 11.9% (P<0.01) and decreased Km by 18% (P<0.05); it also increased production of NO2- by 1.33 folds (P<0.05) and NOS activity by 1.2 folds (P<0.05). Especially, the attack of angina and patient ECG were greatly improved after intravenous L-Arg infusion. Conclusion: L-Arg-NO pathway is impaired in MVA patients, which might be responsible for the endothelium-dependent vascular relaxation in MVA patients. Intravenous L-Arg infusion may benefit the impaired function of L-Arg-NO transport in patients with MVA.
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@# ObjectiveTo investigate the role of apoptosis played in myocardial hypertrophy and the effect of L-arginine (L-Arg) on the pathogenesis.Methods36 rats were randomly divided into the control group, model group and L-Arg treating group. The animal model of over-loading myocardial hypertrophy was made, and systolic blood pressure (SBP)and the cardiac indexes were measured, spectrophotography and flow cytometry were used to detect the content of nitric oxide (NO), activity of superoxide dismutase (SOD) and apoptosis rate.ResultsIn the model group, SBP, cardiac indexes and myocardial apoptosis rate increased, the content of NO and activity of SOD decreased compared with the control group. While, in the L-Arg treating group, SBP, cardiac indexes and apoptosis rate decreased, the content of NO and the activity of SOD increased compared with the model group.ConclusionMyocardial apoptosis may play an important role in the pathogenesis of myocardial hypertrophy and cause the losing of myocardial cells. L-Arg induces the increasing production of NO and inhibits myocardial apoptosis through increasing the activity of SOD.
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AIM: To study the changes of NO concentrations of different ti ssues in stress rats. METHODS: Add stimulation with experiments employed electric food-shock and noise of busser as stressor for 15 days in SD rats,NO concentrations and BP were measured. RESULTS: In stress group, BPs increased before and after stress stimulation,but decreased levels NO concentrations of plasma, and there was no detectable amounts of NO in auricl e, ventricle, vessel and adrenal. In stress +L-arg group, BPs d id not increase before and after stress stimulation, NO concentrations of plasma increased, but auricle, ventricle, vessel and adrenal maintained the concentrat ions of NO. CONCLUSION: The stress stimulation can increase BP a nd low NO concentration, and L-arg can resist the response.
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Objective To observe the influence of L-Arg supplementation during early postnatal life on renal function of rats with intrauterine growth retardation(IUGR).Mehod Afer establishment of IUGR model with 10% protein diet,rats were divided randomly into 2 groups: IUGR group and L-Arg treated group(LT group).Normal control group(NC group) rats were fed with 20% protein diet.The level of NO,Cr in serum were measured from 1 w to 3 months and UCr,24 h-proteinuria were measured from 3 w to 3 months.Results(1)The levels of serum NO reduced significantly in group IUGR at every stage,not significantly different between group LT and NC,but more in group LT than in group IUGR.(2)The levels of 24h-proteinuria had no significant difference among three groups at 3 w and 2 month,but was significantly higher in group IUGR than group LT and group NC.(3)The Cr levels had no significant difference at every stage among three groups.The UCr level was decreased in group IUGR than group NC at 2 month and than group NC and LT at 3 month.(4)The level of CCr in group IUGR was decreased significantly at 3 w,2 month and 3 month than group LT and group NC.Conclusion L-Arg can increase serum NO and CCr levels and decrease the level of 24h-proteinuria in rats with IUGR.It is one of the important reasons to increase 24h-proteinuria and reduce CCr level for low NO value.