Effects of Epidermal Growth Factor on Lipid Peroxidation and Nitric Oxide Levels in Oral Mucosal Ulcer Healing: A Time-Course Study

Purpose Epidermal growth factor (EGF) has been used as a vulnerary agent. Epidermal growth factor accelerates wound healing. Nitric oxide (NO) is considered to be an important factor which is involved in wound healing. The objective of this study was to examine the effects of interactions between exogenous EGF and NOx which may have either similar or quite opposed properties in the process of oral wound repair on different days. In addition, lipid peroxidation was found to be an indicator of free radical damage. Methods Five-month-old New Zealand albino male rabbits were used for this study. A surgical incision was made in the right mandibula diestema region of the rabbits, which were then divided into controls and EGF implanted groups. All parameters were analyzed by spectrophotometry. Results In the EGF-implanted groups, both the NOx and lipid peroxidation indicator levels significantly decreased in comparison to those of the control groups on the first day after wounding. However, on the 3rd and 5th days after wounding, the NOx levels of the tissue strips also decreased in both modalities, but there was no significant alteration between the 3rd and 5th day after wounding. Conclusion It was concluded that EGF affects oral wound healing by downregulating both the lipid peroxidation and NOx levels, and it may thus be considered to be an oxygen radical scavenger.     

一氧化氮合酶抑制剂对肝硬变鼠肝内阻力的影响

目的:探讨一氧化氮合酶(NOS)抑制剂对肝硬变大鼠肝内阻力的影响。方法:采用肝硬变大鼠原位肝脏灌注模型,观察NOS抑制剂硝基精氨酸(L-NNA)及一氧化氮(NO)合成底物L-精氨酸(L-arg)对大鼠门静脉去甲肾上腺素(NE)反应的影响。结果:应用L-NNA后,正常及肝硬变动物门静脉压力均较单用NE时显著升高,肝硬变动物门静脉压力的升高程度明显小于正常动物。L-arg可以消除L-NNA的作用。结论:NO参与正常及肝硬变动物门静脉压力的调节。肝硬变时,肝内NO合成减少,使肝内阻力进一步升高。     

Effects of a Single Bout of Resistance Exercise on Calcium and Bone Metabolism in Untrained Young Males

Although resistance exercise training appears to increase bone mineral density in the long term, a single bout of resistance exercise could paradoxically induce bone homeostasis disturbance, secondary to metabolic acidosis. To examine this, we obtained fasting blood and 24-hour urine samples from untrained male subjects for 5 subsequent days (control day, exercise day, and three post-exercise days), and investigated the effects of a single bout of resistance exercise on urinary calcium excretion and bone metabolism as indicated by sensitive biomarkers of bone formation and resorption. After an intense bout of resistance exercise, blood and urine became more acidic and renal net acid excretion significantly increased by 44% on the exercise day. Urinary calcium excretion significantly increased by 48% on the exercise day. Plasma procollagen type-I C-terminal concentration significantly decreased by 12% on the next day of the exercise and serum bone-specific alkaline phosphatase activity also significantly decreased by 13% and 9% on days 2 and 3, respectively, after the exercise. There was no significant change in serum osteocalcin concentration. Serum tartrate-resistant acid phosphatase activity significantly decreased by 15% on the day after the exercise and urinary deoxypyridinoline excretion decreased by 22% and 27% on days 1 and 3, respectively, after the exercise. These results suggest that the early response of bone to a bout of resistance exercise in untrained individuals was transient decreases in bone formation and resorption, whereas urinary calcium excretion increased. Received: 19 November 1996 / Accepted: 21 May 1997     

Efflux of Creatine Kinase from Isolated Soleus Muscle Depends on Age,Sex and Type of Exercise in Mice

Elevated plasma creatine kinase (CK) activity is often used as an indicator of exercise-induced muscle damage. Our aim was to study effects of contraction type, sex and age on CK efflux from isolated skeletal muscles of mice. The soleus muscle (SOL) of adult (7.5-month old) female C57BL/6J mice was subjected to either 100 passive stretches, isometric contractions or eccentric contractions, and muscle CK efflux was assessed after two-hour incubation in vitro. SOL of young (3-month old) male and female mice was studied after 100 eccentric contractions. For adult females, muscle CK efflux was larger (p < 0.05) after eccentric contractions than after incubation without exercise (698 ± 344 vs. 268 ± 184 mU·h⁻¹, respectively), but smaller (p < 0.05) than for young females after the same type of exercise (1069 ± 341 mU·h⁻¹). Eccentric exercise-induced CK efflux was larger in muscles of young males compared to young females (2046 ± 317 vs 1069 ± 341 mU · h⁻¹, respectively, p < 0.001). Our results show that eccentric contractions induce a significant increase in muscle CK efflux immediately after exercise. Isolated muscle resistance to exercise-induced CK efflux depends on age and sex of mice.

Key points

• Muscle lengthening contractions induce the highest CK efflux in vitro compared with similar protocol of isometric contractions or passive stretches.
• Muscle CK efflux in vitro is applicable in studying changes of sarcolemma permeability/integrity, a proxy of muscle damage, in response to muscle contractile activity.
• Isolated muscle resistance to exercise-induced CK efflux is greater in female compared to male mice of young age and is further increased in adult female mice.

Key words: Skeletal muscle, eccentric contractions, muscle damage, CK activity     

Effects of High-Dose Creatine Supplementation on Kidney and Liver Responses In Sedentary and Exercised Rats

This study evaluated the effects of high-dose of short-term creatine supplementation (5g.kg^-1.day^-1 to 1 week) and long-term creatine supplementation (1g.kg^-1. day^-1 to 4-8 weeks) on kidney and liver structure and function of sedentary and exercised Wistar rats (Exercise sessions consisted of swimming at 80% of maximal work load supported during 5 days per week with daily sessions of 60 minutes throughout the duration of the supplementation). Seventy- two animals (245 ± 5g) were divided into four groups (n = 18): control diet Sedentary (SED), Creatine diet Sedentary (CRE), control diet Exercised (EXE), and Creatine diet Exercised (EXECRE). Histological and blood biochemical studies were performed after one, four, and eight weeks of creatine supplementation and exercise (n = 6). No differences were found when comparing SED, EXE and EXECRE groups for kidney and liver structure and function at one, four and eight weeks. However, the CRE group showed higher levels of creatinine (1.1 ± 0.2 vs. 0.4 ± 0.1 mg.dl^-1; p < 0.05), and urea (37 ± 3 vs. 19 ± 1 mg.dl^-1; p < 0.05) when compared with all others groups at four and eight weeks. At eight weeks, the CRE group presented increased levels of ALT (41 ± 7 vs. 23 ± 7 U.L^-1; p < 0.05), AST (89 ± 6 vs. 62 ± 5 U.L^-1; p < 0.05), GGT (8.0 ± 0.9 vs. 3.9 ± 1.0 U.L^-1; p < 0.05), and AP (125 ± 10 vs. 69 ± 9 U.L^-1; p < 0.05) also when compared with all others groups. Moreover, the CRE group demonstrated some structural alterations indicating renal and hepatic damage at four and eight weeks, respectively. These results suggest that long-term creatine supplementation (up to 4-8 weeks) may adversely affect kidney and liver structure and function of sedentary but not of exercised rats.

Key points

• Creatine supplementation is an established ergogenic aid in sports and is now claimed to have therapeutical applications in a variety of diseases.
• Although acknowledged, this nutritional supplement is rarely monitored precisely about their possible side effects.
• Previous studies indicated that short-term creatine supplementation associate with the physical exercise may be safe, but the effect of long-term creatine supplementation is still unknown.
• There is a need for further research to elucidate the controversial points refers to renal and hepatic function after creatine supplementation.
• The results of the current study indicate that supraphysiological long-term creatine supplementation (up to 4-8 weeks) may adversely affect kidney and liver structure and function of sedentary but not of exercised rats.

Key words: Creatine monohydrate, hepatic metabolism, kidney metabolism, swimming training, sports supplements, toxicology.     

氟烷七氟醚对酶诱导缺氧大鼠脂过氧化反应的影响（氟烷性肝炎的研究Ⅰ）

雄性ＳＤ大鼠饮用含苯巴比妥（１ｍｇ／ｍｌ）的饮水一周后，随机分为６组，每组６例：ＮＣ，２１％Ｏ２／７９％Ｎ２；ＨＣ，１４％０；１８６％Ｎｅ；ＮＨ，２１％Ｏ２／７９％Ｎ２／１．２ＭＡＣ氟烷；ＨＨ，１４％Ｏ２／８６％Ｎ２／１．２ＭＡＣ氟烷；ＮＳ，２１％Ｏ２／７９％Ｎ２／１．２ＭＡＣ七氟醚；ＨＳ，１４％Ｏ２／８６％Ｎ２／１．２ＭＡＣ七氟醚。吸入时间１ｈ，２４ｈ后测定血浆及肝匀浆中ＭＤＡ、ＳＯＤ、游离琉基的含量。结果ＨＨ、ＮＨ组肝匀浆及血浆中ＭＤＡ、ＳＯＤ的含量均高于其它各组（Ｐ＜０．０１，Ｐ＜０．０５），余各组间均无显著差异（Ｐ＞０．０５）。ＮＨ、ＨＨ组血浆及肝匀浆中游离琉基的含量显著低于其它各组（Ｐ＜０．０１）。提示氟烷所致的肝脂过氧化反应增强的作用可能与其肝毒性有关，而七氟醚无促进肝脏脂过氧化反应增强的作用。     

Effects of Nitric Oxide on Detrusor Relaxation

Purpose

Recently we (1994) reported the photo-induced adequate nitric oxide (PIANO) system, in which an NO- or NO₂-carrying molecule which has been photoactivated to release NO, could be exploited to investigate the role of NO in various smooth muscle functions. This study was designed to characterize the effect of nitric oxide (NO) exploiting PIANO on rat detrusor relaxation by isometric tension recording and measuring changes in cGMP content.

Materials and Methods

Exposure to ultraviolet light was used (1 to 60 seconds) to evoke PIANO in the presence of streptozotocin, an NO-carrier, and N^omega-nitro-L-arginine (L-NOARG), an NO₂-carrier. During relaxation the cyclic guanosine monophosphate (cGMP) content was measured by radioimmunoassay.

Results

Rat detrusor strips were reversibly relaxed upon NO generation via PIANO. Pyrogallol, an O₂ generator, significantly (p less than 0.01) diminished PIANO-mediated relaxation. During PIANO-mediated relaxation, the tissue level of cyclic GMP significantly (p less than 0.05) increased over that of the control. Furthermore, methylene blue, a guanylate cyclase inhibitor, significantly (p less than 0.01) inhibited both the relaxation and the increase of cGMP.

Conclusion

We concluded that rat detrusor muscle was capable of responding to NO, and these findings might lead to a treatment for bladder instability and detrusor hyperreflexia, by the use of intravesical instillation of NO donors.     

一氧化氮的肿瘤生物学效应

一氧化氮是人体内活跃的具有多种生物学活性的小分子物质,目前研究表明其在多种肿瘤组织内表达。从肿瘤生物学角度来看,一氧化氮可以体现出许多不同的、有时看来甚至是相互矛盾的生物学效应。这些不同的生物学效应与很多因素有关,其中最重要的是组织中一氧化氮的浓度。高浓度的一氧化氮可以介导肿瘤细胞的凋亡和抑制肿瘤生长;相对低浓度的一氧化氮可促使肿瘤生长和肿瘤细胞增殖,并可以使肿瘤细胞增强对放疗和某些化疗药物的耐受性。一氧化氮对肿瘤生长的双向调节作用为肿瘤的研究提供了一个新的方向。     

Effects of Intracisternal Methylprednisolone on Lipid Peroxidation in Experimental Subarachnoid Haemorrhage

Summary  The efficacy of intracisternal methylprednisolone was examined on lipid peroxidation in a canine subarachnoid haemorrhage (SAH) model. The concentration of lipid peroxides increased significantly in the cerebrospinal fluid (CSF) supernatant on Day 4, and also in the arterial wall on Day 7. Intracisternal administration of methylprednisolone reduced markedly the products of lipid peroxidation both in CSF and in the arterial wall. The findings suggest that lipid peroxidation might play a significant role in the genesis of vasospasm after SAH, and that direct administration of methylprednisolone into the subarachnoid space might reduce lipid peroxides in the arterial wall and so influence the prevention of vasospasm.     

衰老对大鼠阴茎海绵体NOSⅠ的表达和NOS活性的影响

目的 :探讨衰老对大鼠阴茎海绵体一氧化氮合酶Ⅰ (NOSⅠ)mRNA、蛋白的表达和NOS活性的影响。　方法 :30只雄性SD大鼠按不同月龄分为成年组、老年组和衰老组 ,应用Western印迹、RT PCR方法分别检测不同年龄组阴茎海绵体NOSⅠ蛋白及mRNA的表达 ;用紫外分光光度计测定不同年龄组阴茎海绵体NOS的活性。　结果 :成年组NOSⅠ 蛋白的表达量最高 ,老年组和衰老组显著降低 ,分别为成年组的 75 .6 %和 6 1.2 % ;NOSⅠmRNA的表达与蛋白表达的变化一致 ;老年组NOS活性与成年组差异无显著性 (P >0 .0 5 ) ,衰老组NOS活性明显降低 ,是成年组的70 .4 % ,并且差异非常显著 (P <0 .0 1)。　结论 :衰老引起NOSⅠ 蛋白及mRNA的表达降低和NOS活性的显著降低 ,可能是老年性阴茎勃起功能障碍的主要机制之一。     

The Effect of One Session of Muscle Soreness-Inducing Weight Lifting Exercise on WBC Count, Serum Creatine Kinase, and Plasma Volume

The purpose of this study was to assess white blood cell (WBC) count, serum creatine kinase (CK), and plasma volume (PV) changes following a single session of soreness-inducing exercise. Sixteen untrained males, aged 18 to 38 years, were exercised at 80% of one repetition maximum until failure for three sets on seven different weight lifting resistive machines. Measurements were done prior to and up to 84 hours postexercise on: a) delayed onset muscle soreness (DOMS), utilizing a four-point pain scale on seven muscles; b) CK; c) WBC count; and d) PV change, indirectly assessed by hematocrit and hemoglobin. One session of weight lifting exercise was found to produce significant postexercise PV elevations, with the peak change occurring at 36 hours (8.9%, p < .05). Significant elevations in WBC count were found 12 hours postexercise (7900 cells/mul, p < .05) when corrections were made for PV increases. In addition, DOMS and CK were significantly increased postexercise, with the highest levels occurring at 36 hours (9/21 pain scale units, p < .05) and 84 hours (5756 IU/L, p < .001). These results suggest that one session involving high intensity weight lifting exercise may induce muscle soreness and elevate WBC count, CK, and plasma volume. The aggressive initiation of a fitness program can trigger delayed muscle discomfort, a possible inflammatory process, and dilate blood parameters that physical therapists may be monitoring. J Orthop Sports Phys Ther 1991;13(6):316-321.     

Effects of Radiation on Protein Oxidation and Lipid Peroxidation in the Brain Tissue

Radiation produces reactive oxygen species that modify macromolecules such as protein and lipid by oxidation and act in many pathological processes, causing serious damage to the brain. This study sought to evaluate the effects of radiation and the protective effect of N-acetylcysteine (NAC) on the brain tissue of guinea pigs based on the levels of lipid peroxidation and protein oxidation. Thirty-two guinea pigs were divided into groups of eight animals each: control group (group I); radiation group (group II); NAC group (group III), and NAC administered before radiation exposure group; (group IV). Guinea pigs in groups II and IV were exposed to Co⁶⁰ radiotherapy using the Source-Axis-Distance = 80 technique. The levels of protein carbonyl content and malondialdehyde (MDA), which is a marker for lipid peroxidation, were investigated by the Evans-Levine and Uchiyama-Mihara methods, respectively. The protein carbonyl and MDA levels of group II were significantly greater than those of group I (P < .01). The protein carbonyl and MDA levels of group IV were lower than those of group II. The difference between the MDA levels of group IV and group II was significant (P < .01); however, the difference in protein carbonyl levels between the two groups was not significant. The results indicated that radiation increased protein oxidation and lipid peroxidation in the brain, and NAC administration before radiation exposure may aid in the treatment by decreasing protein and lipid oxidation.     

一氧化氮在肿瘤生长转移中的作用

目的 探讨一氧化氮(NO)在肿瘤生长、转移中的作用。方法 对近年来有关文献加以综述。结果 NO在肿瘤生长转移中具有双重作用，一方面NO通过干扰肿瘤细胞代谢，引起DNA损伤，形成高毒性的羟自由基，诱导肿瘤细胞凋亡，介导巨噬细胞和内皮细胞的杀瘤作用，发挥其抗肿瘤的作用；另一方面NO通过调节细胞增殖相关基因的表达，可诱导肿瘤血管形成，而具有促肿瘤生长作用。结论 选择性阻断或诱导NO的合成，使其发挥抗肿瘤作用，将为肿瘤的治疗提供新的思路和方法。     

Effect of Moderate Altitude on Peripheral Muscle Oxygenation During Leg Resistance Exercise in Young Males

Training at moderate altitude (~1800m) is often used by athletes to stimulate muscle hypoxia. However, limited date is available on peripheral muscle oxidative metabolism at this altitude (1800AL). The purpose of this study was to determine whether acute exposure to 1800AL alters muscle oxygenation in the vastus lateralis muscle during resistance exercise. Twenty young active male subjects (aged 16 – 21 yr) performed up to 50 repetitions of the parallel squat at 1800AL and near sea level (SL). They performed the exercise protocol within 3 h after arrival at 1800 AL. During the exercise, the changes in oxygenated hemoglobin (OxyHb) in the vastus lateralis muscle, arterial oxygen saturation (SpO₂), and heart rate were measured using near infrared continuous wave spectroscopy (NIRcws) and pulse oximetry, respectively. Changes in OxyHb were expressed by D_eff defined as the relative index of the maximum change ratio (%) from the resting level. OxyHb in the vastus lateralis muscle decreased dramatically from the resting level immediately after the start of exercise at both altitudes. The D_eff during exercise was significantly (p < 0.001) lower at 1800AL (60.4 ± 6.2 %) than at near SL (74.4 ± 7.6 %). SpO₂ during exercise was significantly (p < 0.001) lower at 1800AL (92.0 ± 1.7 %) than at near SL (96.7 ± 1.2 %). Differences (SL – 1800AL) in D_eff during exercise correlated fairly strongly with differences in SpO₂ during exercise (r = 0.660). These results suggested that acute exposure to moderate altitude caused a more dramatical decrease in peripheral muscle oxygenation during leg resistance exercise. It is salient to note, therefore, that peripheral muscle oxygenation status at moderate altitude could be evaluated using NIRcws and that moderate altitudes might be effectively used to apply hypoxic stress on peripheral muscles.

Key Points

• The change in muscle oxygenation during the parallel squat at 1800 altitude and near sea level was investigated using near infrared continuous wave spectroscopy (NIRcws)
• The muscle oxygenation during exercise at 1800 altitude decreased more dramatically compared to sea level.
• NIRcws could help to provide a better understanding of exercising muscle metabolism at moderate altitude.

Key words: NIRcws, muscle oxygenation, moderate altitude, parallel squat, SpO₂     

NO对前列腺及阴茎勃起功能的调节作用

一氧化氮是一种不稳定的低分子有害气体 ,同时它又是一种生物活性物质 ,参与了多种疾病的病理生理过程。一氧化氮在体内由L 精氨酸在一氧化氮合成酶的作用下生成 ,作为一种非肾上腺能非胆碱能神经递质 ,对动物和人的生殖泌尿器官平滑肌张力起着重要的调节作用。本文简要介绍一氧化氮在体内的产生机制和分布 ,并着重概述一氧化氮对平滑肌舒张调节作用机理 ,及其在非手术治疗前列腺增生导致下尿路梗阻及改善阴茎勃起功能障碍方面的临床应用。     

一氧化氮对精子的调节作用及影响

一氧化氮 (NO)是一种不稳定的小分子有害气体 ,又是一种生物活性物质 ,参与了多种疾病的病理生理过程。NO在体内由L 精氨酸在一氧化氮合酶的作用下生成。它分布于睾丸、附睾及输精管等组织中 ,也分布于精子的顶体和尾部 ,对生精过程 ,精子活力、活率 ,受精能力以及精子脂质过氧化反应等具有重要的影响和双向调节作用。低浓度NO有益于增加精子活力、活率 ,降低精子脂质过氧化反应 ,提高精子的受精能力 ;高浓度NO对精子具有损伤作用 ,使精子活力、活率下降 ,脂质过氧化反应加强。本文简要介绍了NO在体内的产生机制 ,并着重概述了NO对精子的调节作用及影响。     

尼群地平对缺血再灌注肺脂质过氧化反应的影响

目的探讨肺缺血再灌注损伤的发病机理，观察尼群地平的防治效果。方法７２只大鼠随机分成假手术组、缺血再灌注组和治疗组，采用肺在体温缺血再灌注损伤模型，于缺血４５分钟、再灌注后１小时、２小时、４小时取损伤肺组织测丙二醛（ＭＤＡ）、超氧化物歧化酶（ＳＯＤ）和总钙含量。结果缺血再灌注组各时相肺组织ＭＤＡ含量上升（Ｐ＜０．０５），ＳＯＤ含量显著下降（Ｐ＜０．０５），总钙含量显著升高（Ｐ＜０．０５），尼群地平可减轻肺组织ＭＤＡ和组织总钙含量的升高（Ｐ＜０．０５）。结论钙超载和自由基反应共同参与了肺缺血再灌注损伤，二者可能相互影响，相互促进；尼群地平通过阻滞钙通道，影响自由基系统而对缺血再灌注肺起保护作用     

Effect of Short‐term Hypothermia on Lipid Peroxidation and Antioxidant Enzyme Activity in Rats

This experiment was carried out to determine the effect of short‐term hypothermia on blood malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GSH‐Px) and glucose‐6‐phosphate dehydrogenase (G‐6‐PD) concentrations in rats. Twenty Sprague–Dawley rats were used weighing 180–200 g and on average 3.5 months old. They were randomly divided into two experimental groups: control (without cooling) and hypothermic (with cooling). The rats of the hypothermic group were cooled by immersion into cold water (10–12 °C), and the control rats were immersed into water of body temperature (37 °C) up to the neck without using any anaesthetic or tranquilizer for 3 min Rectal body temperatures of both groups were measured and blood samples to analyse MDA, GSH, SOD, GSH, GSH‐Px and G‐6‐PD were collected immediately after the treatment. It was found that the MDA level was higher and the GSH and G‐6‐PD levels were lower in the hypothermic group than those in the controls. There was no difference between the control or hypothermic group regarding SOD or GSH‐Px levels. It is concluded that acute hypothermia increased the lipid peroxidation and decreased the GSH and G‐6‐PD levels in rats.