顺铂耳毒性大鼠耳聋模型的研究

摘要 目的：探讨顺铂对大鼠造成的听力损伤及耳蜗细胞形态学变化。方法：体内实验,运用顺铂腹腔注射的方法,连续七天注射,通过听性脑干反应检测,观察顺铂对不同日龄的大鼠听力损伤情况;测听后取耳蜗,通过基底膜铺片和冰冻切片的免疫荧光染色,观察听力损伤后对耳蜗毛细胞和螺旋神经元的影响。体外实验,耳蜗器官培养免疫荧光染色,观察顺铂对耳蜗毛细胞和螺旋神经元的影响。结果：顺铂具有耳毒性,会对大鼠听力造成损伤,高频听力损伤更加严重,而且对不同日龄的大鼠造成的听力损失不同,小日龄的大鼠对顺铂耳毒性更加敏感。体内实验,顺铂耳毒性造成听力损失,会引起大鼠耳蜗毛细胞的缺失,但未观察到明显的螺旋神经元缺失,也没有观察到明显的Cleaved caspase-3阳性螺旋神经元细胞。体外实验,可以观察到顺铂同时引起毛细胞和螺旋神经元产生明显的损伤。结论：体、内外实验,都可以建立稳定的顺铂耳毒性大鼠耳聋模型,对研究顺铂损伤耳蜗毛细胞的发生机制和保护奠定了实验基础。     

川芎嗪抗链霉素耳毒性作用及其对豚鼠耳蜗外毛细胞钾通道的影响

本文旨在研究川芎嗪（tetramethylpyrazine,TMP）拮抗链霉素耳毒性作用及其对豚鼠耳蜗外毛细胞K^＋通道的影响,探讨TMP拈抗链霉素耳毒性的离子通道机制。60只豚鼠随机分为6组,应用听觉脑干反应（auditory brainstem response,ABR）技术检测豚鼠ABR听阈,观测TMP的抗链霉素耳毒作用;并采用全细胞膜片钳技术观察TMP对耳蜗外毛细胞Ca^2＋敏感艮电流的影响。结果显示,TMP明显降低链霉素导致的豚鼠ABR听阈升高,提示TMP具有抗链霉素耳毒性作用;TMP能明显增大豚鼠耳蜗外毛细胞Ca^2＋敏感艮电流,并呈浓度依赖关系。结果提示,TMP通过增大艮通道电导而拮抗链霉素耳毒性作用。     

头孢哌酮钠和卡那霉素在豚鼠化脓性中耳炎中的作用及耳毒性机制研究

目的探讨头孢哌酮钠和卡那霉素在豚鼠化脓性中耳炎中的作用、耳毒性。方法 A、B、C组均应用金黄色葡萄球菌菌苗中耳腔注射法制备化脓性中耳炎模型。然后分别应用生理盐水、头孢哌酮钠滴耳液和卡那霉素滴耳液中耳腔给药治疗,各0.2 ml/次,2次/天,连续给药7天。听性脑干反应(ABR)检测豚鼠鼓室内注射金黄色葡萄球菌前后以及抗生素滴耳后ABR阈值。脓性分泌物评分和菌落计数。耳蜗基底膜铺片:毛细胞计数和形态学观察。结果 A组(生理盐水组)、B组(头孢哌酮钠组)、C组(卡那霉素组)实验后ABR听阈分别为(46.00±5.1)dB peSPL(peSPL:等效峰值声压级),(35.25±4.9)dB peSPL,(42.25±5.2)dB peSPL(差别主要是给药后,造模前后无差别)。脓性分泌物评分分别为A组(2.33±0.4)、B组(1.65±0.4)、C组(1.53±0.3)。细菌培养计数分别为A组(117±10.5)、B组(63±6.9)、C组(49±6.1)。A组和B组毛细胞未见缺失,纤毛和表皮板完好,结构正常,C组毛细胞大片缺失,相应部位的纤毛和表皮板也见缺失。结论头孢哌酮钠滴耳液的抗菌效应可以应用于化脓性中耳炎的治疗,且无耳毒性。卡那霉素滴耳液虽然抗菌效应强,但耳毒性较强,所以不推荐作为治疗化脓性中耳炎的一线用药。     

内耳形态学和生理指标对缺铁性肾虚耳聋大鼠模型的评价作用

目的探讨耳蜗显微结构和生理指标对缺铁性肾虚耳聋大鼠模型的评价作用。方法选用体重30～32 g、无耳疾、听性脑干反应(auditory brainstem response,ABR)阈值正常的1～2周龄SPF级SD大鼠120只,雌雄分养,分为缺铁组80只、正常对照组40只,饲养时间12周;以出现肾虚证和至少一耳ABR阈值≥15 dB,作为判断肾虚耳聋的标准,获得缺铁性肾虚耳聋大鼠22只,从中选取肾虚耳聋大鼠20只,同时以20只正常大鼠作对照。观察耳蜗血管纹、螺旋器等耳蜗显微结构变化,检测ABR阈值以及血红蛋白和血清铁等指标的变化。结果实验组和正常对照大鼠的血红蛋白和血清铁分别为11.80 g/L,4.5μmol/L和45.9 g/L,22.23μmol/L,ABR阈值分别为(30±5)dB和(10±5)dB;实验组血管纹血管明显减少;螺旋器毛细胞听毛有缺失、倒伏现象。结论缺铁性肾虚耳聋大鼠血红蛋白、血清铁和ABR阈值,以及耳蜗血管纹、螺旋器等耳蜗显微结构变化等指标,均较为稳定,是较好的评价指标。     

丹参注射液对庆大霉素耳中毒豚鼠耳蜗氧自由基生成的影响

目的:研究丹参注射液(SM)对庆大霉素(GM)耳中毒豚鼠耳蜗氧自由基生成的影响,探讨SM对GM耳毒性损伤的保护作用及其机制.方法:检测豚鼠耳蜗组织中超氧化物歧化酶(SOD)活力和丙二醛(MDA)含量,结合听性脑干反应(ABR)测试及透射电镜技术.结果:经GM处理的耳蜗组织中SOD活力明显下降,MDA含量则明显增加(P＜0.01),且与ABR阈值升高高度相关(|r|＞0.8,P＜0.05).同时接受SM的动物,其耳蜗组织中SOD活力明显升高(P＜0.01),MDA含量则明显减少(P＜0.05),且听功能显著改善.电镜观察显示耳蜗形态学改变与听力变化相一致.结论:氧自由基及其引发的脂质过氧化参与了GM耳中毒过程,SM可通过提高耳蜗组织中SOD活力,防止脂质过氧化,减轻GM的耳蜗毒性,改善听功能.     

丹参注射液对顺铂致听力损伤的拮抗作用

目的:探讨丹参注射液对顺铂致小鼠耳毒性的保护作用,为顺铂耳毒性作用的防治提供实验依据.方法:应用听觉脑干反应(ABR)检测给药前后各组小鼠不同滤波click听力阈值的变化.结果:顺铂可引起小鼠体重明显下降和各滤波click听力阈值的升高.而丹参拮抗组小鼠给药前后体重和ABR听力阈值的改变明显低于单纯顺铂给药组,并呈剂量依赖关系.结论:丹参可明显减轻顺铂对小鼠的听力损伤.     

白噪声对听觉脑干电反应(ABR)和耳蜗电图(ECochG)的影响

本文通过20例听力正常人和10例听力正常豚鼠研究了白噪声对耳蜗电图(ECochG)和听觉脑干电反应(ABR)的干涉作用。实验结果表明,白噪声比短声(信号)的声强级低30dB(SL)以上时,ECochG和ABR的振幅仅轻微减小。白噪声与短声的声强级相等时,ECochG与ABR的振幅和出现率会明显受到干涉而减小,甚至完全消失。但是,此时的耳蜗微音器电位(CM)并未观察到有明显的变化。这意味着白噪声对ECochG和ABR的干涉作用主要与围绕毛细胞基底部的突触产生的抑制密切相关。由于白噪声对ABR各波的干涉有些差异,所以认为这种抑制,可能既包括脑中抑制也包括侧方抑制。     

甲状腺激素对豚鼠卡那霉素中毒性耳聋的预防作用

卡那霉素、庆大霉素等抗生素常引起耳聋,目前尚无较好的防治方法。卡那霉素对内耳的毒性作用,主要先影响有关的酶功能,继而破坏毛细胞而致聋。甲状腺激素具有促进蛋白质合成、增强细胞生物氧化的功能。因此可能具有减轻卡那霉素耳毒性的作用。本实验以耳廓反射、内耳生物电及耳蜗铺片为指标,观察甲状腺激素对卡那霉素耳中毒的预防。实验豚鼠分两组,各13只,对照组每天注射卡那霉素300mg/kg,共10天;甲状腺素组先隔天服甲状腺片20mg共四次,以后给予与对照组相同剂量卡那霉素,同时仍隔天服甲状腺片20mg直至停药后16天,前后总共服17次。结果:(1)耳廓反射阈变化,对8、4、2KHz三个频率听力均下降的耳,对照组为11只耳,甲状腺素组为3只耳,两者差异显著。听力下降的频率范围及程度,对照组比甲状腺素组更大。对照组听力下降开始出现的时间明显早于甲状腺素组;(2)内耳生物电,0～80dβ不同程度短声引起的耳蜗微音器电位与听神经动作电位幅值甲状腺素组动物均高于对照组;(8)耳蜗铺片,对照组大部分动物耳蜗各回的毛细胞严重变性缺损,甲状腺素组耳蜗病变仅局限在底回。以上结果表明甲状腺激素能减轻卡那霉素的耳毒性,为耳毒性抗生素致聋的防治提供了一条新的研究途径。     

脑细胞生长肽对GM耳毒性的预防作用

目的：观察脑细胞生长肽（cerebral cell growth peptide,CCGP)对庆大霉素（gentamicin,GM)引起的豚鼠耳中毒的预防作用）。方法：用脑干听觉诱发电位（brainstem auditory evoked potential,BAEP)和组织化学方法分别检测动物听阀的变化和耳蜗毛细胞线粒体内琥珀酸脱氢酶（succinate dehydrogenase,SDH)及溶酶体内的酸性磷酸酶（acid phosphatase,ACP)活性变化,并在三组动物进行耳蜗受损毛细胞计数。结果：CCGP能降低GM引起的BAEP反应阈的上升幅度,保护耳蜗毛细胞SDH和维持溶酶体的完整性,减轻毛细胞的损伤。结论：CCGP能降低GM的中毒性;保护耳蜗毛细胞SDH,维持毛细胞的能量代谢,减少溶酶体损伤,降低溶酶体内水解酶逸出引起的毛细胞自溶性损伤,可能是CCGP预防GM耳毒性的机制之一。     

丹参注射液对链霉素耳中毒豚鼠耳蜗iNOS表达的影响

目的: 探讨链霉素(SM)耳中毒过程中豚鼠耳蜗iNOS表达,以及丹参注射液(DS)的拮抗作用.方法: 应用光镜、电镜、免疫组化及图像分析技术,结合听性脑干反应(ABR)测试.结果: 用药10d后,SM组ABR阈值明显升高,DS SM组ABR阈值明显低于SM组,差异显著(P<0.01).光镜及电镜下可见SM组柯蒂氏器、内外毛细胞、螺旋神经节细胞、血管纹损伤严重,DS SM组损伤较轻.SM组iNOS在柯蒂氏器、内外毛细胞、螺旋神经节、血管纹的表达明显高于DS SM组.结论: SM耳中毒时ABR阈值升高,iNOS表达增强.DS能有效的降低SM所致的ABR阈值升高,并抑制iNOS的过量表达,从而减轻SM的耳毒性损伤,提示DS对SM耳毒性损伤有保护作用.     

Resistant starch reduces colonic and urinary p-cresol in rats fed a tyrosine-supplemented diet,whereas konjac mannan does not

The effect of resistant starch (RS) and konjac mannan (KM) to maintain and improve the large intestinal environment was compared. Wistar SPF rats were fed the following diets for 4 weeks: negative control diet (C diet), tyrosine-supplemented positive control diet (T diet), and luminacoid supplemented diets containing either high-molecular konjac mannan A (KMAT diet), low-molecular konjac mannan B (KMBT diet), high-amylose cornstarch (HAST diet), or heat-moisture-treated starch (HMTST diet). The luminacoid-fed group had an increased content of short-chain fatty acids in the cecum. HAS caused a significant decrease in p-cresol content in the cecum, whereas KM did not. Urinary p-cresol was reduced in the HAST group compared with the T group, but not the KM fed groups. Deterioration in the large intestinal environment was only improved completely in the HAST and HMTST groups, suggesting that RS is considerably more effective than KM in maintaining the large intestinal environment.     

Actividad del sistema neuronal LHRH en un modelo animal de retraso del crecimiento

ObjectiveMild and chronic energy restriction results in growth retardation with puberal delay, a nutritional disease known as nutritional dwarfing (ND). The aim of the present study was to assess the profile of hypothalamic luteinizing hormone-releasing hormone (LHRH) release, at baseline and under glutamate stimulation, in ND rats to elucidate gonadotrophic dysfunction. Reproductive ability during refeeding was also studied.Material and methodsAt weaning, 60 male rats were assigned to two groups of 30 animals each: a control and an experimental group. Control rats were fed ad libitum with a balanced rodent diet. The experimental group received 80% of the diet consumed by the control group for 4 weeks. After 4 weeks of food restriction, the ND group was fed freely for 8 weeks. Ten rats from each group were sacrificed every 4 weeks for assays.ResultsAt week 4, body weight and length were significantly diminished in the experimental group vs. the control group (p<0.001). No changes were observed in LHRH baseline release, pulse frequency or amplitude in the experimental group compared with the control group at any time. However, under glutamate stimulation, LHRH release was significantly higher in ND rats than in control rats at week 4 (p<0.05). Refeeding the ND group allowed the rats to reach overall growth and reproductive ability.ConclusionsThe results of the present study suggest that the response to the facilitatory effect of glutamate on LHRH release in post-restricted ND rats is probably related to a lesser central nervous system maturation in relation to their chronological age. The adequate somatic growth and normal reproductive ability attained with refeeding suggest the reversibility of the two energetically costly processes compromised by global, mild and chronic food restriction.     

No effects of UMTS exposure on the function of rat outer hair cells

UMTS communication devices are becoming common in everyday use. This could raise public concern about their possible detrimental effects on human health. The aim of this study, in the framework of the EMF nEAR Project, was to evaluate possible influence of UMTS electromagnetic fields (EMF) exposure on cochlear outer hair cells' (OHCs) functionality in laboratory animals. Forty‐eight male Sprague–Dawley rats were locally exposed (right ear) or sham‐exposed to a controlled UMTS EMF, frequency of 1946 MHz, at SAR level of 10 W/kg, 2 h a day, 5 days a week, for 4 weeks. A group of 12 rats treated with kanamycin (KM) was also included as positive control. Rats were tested by recording Distortion Product Otaoacoustic Emissions (DPOAEs), a non‐invasive test capable of assessing the status of the OHCs in the inner ear. DPOAEs were performed before, during (one or three times a week) and after (1‐week) exposure to the EMF. The analysis of the data shows that no statistically significant differences were found between the audiological signals recorded from the different experimental groups. The ototoxic effect of KM has been confirmed. Bioelectromagnetics 30:385–392, 2009. © 2009 Wiley‐Liss, Inc.     

Morphological and morphometric study on the effect of simulated microgravity on rat testis

The present study was undertaken to determine the effect of simulated microgravity on the testis of the rats and to evaluate the possibility of spermatogenesis failure in space environment. Fifty-four adult male albino rats were used in this study. They were divided equally into intact control, stress control and experimental groups. The rats of the intact control group (Group Ia) were kept without intervention. The rats of both the stress control and experimental groups were subjected to inguinal canal ligation and tail-suspension. In the stress control group (Group Ib) the hindlimbs were not elevated above the floor of the housing units whereas in the experimental groups the hindlimbs were elevated for one week (Group II) and six weeks (Group III), respectively. In a third experimental group (Group IV) the rats were hindlimb-suspended for six weeks followed by another six weeks without suspension to allow recovery. Prior to sacrifice, the animals were weighed and anesthetized, and the testes were excised and weighed. Testicular specimens were processed for histological, histochemical and morphometric studies. The results of the present study revealed that only after six weeks of hindlimb-suspension, the rats showed a significant decline in testicular weight compared with the control groups. Histologically, few abnormalities were observed in some seminiferous tubules in one-week hindlimb-suspended group. Spermatogenesis was significantly reduced by six-week of hindlimb-suspension marked by atrophy of the testes and loss of all germ cells, except a few spermatogonia. Spermatogenesis was partially restored in the recovery group. In all groups the appearance of Sertoli cells remained the same. Proliferation of Leydig cells was observed in the experimental groups. It is concluded that spermatogenesis is severely inhibited by six weeks of hindlimb-suspension and that it is partially restored following six weeks of recovery. This study provides further insights regarding the serious effects of long-term exposure to microgravity on the testes of mammals, including human beings.     

共轭亚油酸对高脂血症大鼠脂质代谢及visfatin基因表达水平的影响

目的建立高脂血症大鼠模型,分析共轭亚油酸（CLA）对其脂质代谢和visfatin基因表达水平的影响,为进一步研究CLA对脂肪代谢的调控机制奠定基础。方法用高脂饲料饲喂雄性Wistar大鼠,4周后断尾采血测定血清甘油三酯（TG）、总胆固醇（CHO）和血糖（GLU）含量,将构建成功的高脂血症大鼠分为实验组和对照组,实验组每天定时灌胃CLA（0.8 mL/0.1 kg）,每周定时称重,记录采食量;4周后眼球采血,测定血清中GLU、CHO、TG、低密度脂蛋白（LDL）、高密度脂蛋白（HDL）水平;断颈处死大鼠,分离体脂并提取肝脏总RNA,半定量RT-PCR分析visfatin基因表达水平。结果高脂饲料饲喂4周后,模型组大鼠血清TG、CHO、GLU明显高于对照组大鼠（P〈0.05）,表明高脂大鼠模型构建成功。灌胃CLA 4周后,实验组大鼠体重、体脂和采食量低于对照组大鼠（P〈0.05）,血清中GLU、CHO、TG、LDL含量明显降低,但实验组HDL浓度升高。RT-PCR实验结果表明,实验组大鼠visfatin基因表达水平明显低于对照组大鼠（P〈0.05）。结论CLA能降低高脂血症大鼠摄食量,改善高血脂大鼠脂质代谢,并能降低visfatin基因的表达水平。     

肿瘤坏死因子α在大鼠肝肺综合征发病机制研究

目的:探讨TNF-α在大鼠肝肺综合征形成中的作用与机制.方法:采取胆总管结扎方法建立肝肺综合征模型,随机将45只大鼠分为对照组(非手术组)、模型组(胆总管结扎组)和实验组(胆总管结扎+抗TNF-α单克隆抗体组),每组15只,实验组于术后3周、4周、5周、6周分别给予腹腔注射抗TNF-α单克隆抗体;术后4周、5周、6周、...     

超氧化物歧化酶和Bcl-2在实验性精索静脉曲张大鼠睾丸中的变化

目的:建立大鼠实验性精索静脉曲张(experimental varicocele EV)的模式,测量睾丸中超氧化物歧化酶(superoxide dismutaseSOD)活性和Bcl-2的表达。方法:将40只雄性青春期Wistar大鼠随机分为EV8周组和12周组(各12只)和相应的假手术对照组2组(各8只),通过部分结扎左肾静脉建立大鼠EV模型,分别于术后8周、12周处死动物,测左侧精索静脉直径,用比色法测SOD 活力,免疫组化法测Bcl-2的表达。结果:成功建立了EV型,与相应的对照组相比左侧精索静脉直径明显增大(P<0.01)。光学显微镜下观察睾丸组织,发现大鼠睾丸生精上皮退变,曲细精管萎缩,间质水肿和精子发育阻滞。EV组双侧睾丸的SOD活性显著低于相应的对照组(P<0.01),左侧睾丸比右侧睾丸更低,但无明显统计学意义(P>0.05)。EV组双侧睾丸间质细胞中Bcl-2的染色指数与相应的对照组相比均显著降低(P<0.01),左侧睾丸染色指数比右侧睾丸下降更明显(P<0.01),EV12周组与 EV8周组相比,EV12周组染色指数更低(P<0.05)。SOD活性与Bcl-2的染色指数在0.01水平有显著相...     

高血压大鼠心肌2型小电导-Ca2+-激活-K+通道蛋白(SK2)表达的变化*

目的:观察高血压大鼠心肌细胞2型小电导-Ca²⁺-激活-K⁺(SK2)通道蛋白表达情况。方法:12只健康成年雄性SD大鼠随机分为对照组(5只)和实验组(7只),实验组采用N’-硝基-L-精氨酸(L-NNA 15 mg/(kg·d))腹腔注射制备高血压模型,对照组以等体积生理盐水腹腔注射,每天称量大鼠体重,每周测量血压及心电图变化,4周后处死大鼠取心脏;采用Western blot的方法检测心肌SK2通道蛋白表达水平。结果:给药4周后,与对照组相比,实验组大鼠血压明显升高(P＜0.05),心电图QRS时长和R-R间期延长,实验组大鼠心房组织和心室组织SK2通道的表达均明显升高(1.12±0.18 vs 0.52±0.99,1.64±0.26 vs 0.99±0.22, P＜0.05)。结论:高血压模型大鼠心房和心室SK2通道表达增加,其可能是导致高血压模型大鼠出现心律失常的机制之一,为高血压疾病的治疗和预后提供新的思路和策略。     

构树黄酮对小鼠学习记忆的影响(英文)

Morris水迷宫在啮齿目动物的空间学习与记忆的研究中被广泛使用。研究表明摄食抗氧化剂能够增强空间学习与记忆能力。本文目的在于研究构树黄酮对昆明小鼠的空间学习与记忆能力的影响。用构树黄酮固体脂质纳米粒对小鼠灌胃4周,然后进行Morris水迷宫测试。与对照组相比,实验组小鼠的各项指标均有显著改善。这表明构树黄酮能显著增强小鼠的空间学习与记忆能力。同时研究还表明构树黄酮对小鼠的生长发育没有影响。     

Energetic,oxidative and ionic exchange in rat brain and liver mitochondria at experimental audiogenic epilepsy (Krushinsky–Molodkina model)

The role of brain and liver mitochondria at epileptic seizure was studied on Krushinsky-Molodkina (KM) rats which respond to sound with an intensive epileptic seizure (audiogenic epilepsy). We didn't find significant changes in respiration rats of brain and liver mitochondria of KM and control rats; however the efficiency of АТР synthesis in the KM rat mitochondria was 10% lower. In rats with audiogenic epilepsy the concentration of oxidative stress marker malondialdehyde in mitochondria of the brain (but not liver) was 2-fold higher than that in the control rats. The rate of H₂O₂ generation in brain mitochondria of КМ rats was twofold higher than in the control animals when using NAD-dependent substrates. This difference was less pronounced in liver mitochondria. In KM rats, the activity of mitochondrial ATP-dependent potassium channel was lower than in liver mitochondria of control rats. The comparative study of the mitochondria ability to retain calcium ions revealed that in the case of using the complex I and complex II substrates, permeability transition pore is easier to trigger in brain and liver mitochondria of KM and КМs rats than in the control ones. The role of the changes in the energetic, oxidative, and ionic exchange in the mechanism of audiogenic epilepsy generation in rats and the possible correction of the epilepsy seizures are discussed.