Testosterone and androstanediol production by regenerating Leydig cells in the ethylene dimethane sulphonate-treated mature rat

Mature (60-65 day old) male Sprague-Dawley rats received a single intraperitoneal injection of ethylene dimethane sulphonate (EDS; 100 mg/kg) and were subsequently killed at various times from day 2 to day 40 post-treatment. Testes were removed from these animals and age-matched controls and utilized either for light and electron microscopical analyses or for in-vitro assessment of Leydig cell function. Interstitial cells were prepared by collagenase digestion and used to measure 125I-labelled human chorionic gonadotrophin (hCG) binding capacity and androgen production in the presence or absence of hCG or dibutyryl cyclic AMP (dbcAMP). At day 2 after EDS treatment, 125I-labelled hCG binding capacity was reduced to 10% of control values, while the production of testosterone and 5 alpha-androstane-3 alpha, 17 beta-diol (adiol) were non-detectable. Histological observations confirmed the lack of identifiable Leydig cells at day 2-16 after EDS treatment. Between days 24 and 40 post-treatment, Leydig cell regeneration occurred, as indicated by a rise in 125I-labelled hCG binding capacity, increased androgen production and the presence of histologically identifiable Leydig cells. A pattern of adiol production similar to that seen in the immature rat during Leydig cell development was observed with peak synthesis occurring at day 30 post-treatment. Adiol production fell to barely detectable levels by day 36 and remained low at day 40. It is concluded that the steroidogenic pattern of regenerating Leydig cells in the EDS-treated animal is similar to that of developing Leydig cells in the immature animal.     

Evaluation of filling materials in membrane‐protected bone defects. A comparative histomorphometric study in the mandible of miniature pigs.

In recent years, bone grafts and bone substitutes have been increasingly utilized underneath barrier membranes to optimize the treatment outcome of bone reconstructive therapy for defects in the alveolar process. In the present study, 4 different filling materials were evaluated in bone defects of similar dimensions in the mandible of miniature pigs. Blood clots and autografts were used as controls. The defects were covered with barrier membranes and allowed to heal for 4, 12 or 24 weeks. Histologic examination demonstrated that bone repair progressed through a programmed sequence of maturation steps closely resembling the pattern of bone development and growth regardless of whether bone grafts or substitutes were present or not. Histomorphometric analysis showed that autologous bone grafts (autografts) had the best osteoconductive properties during the initial healing period, with 39% of newly formed bone inside the membrane-covered defects at 4 weeks of healing. In addition, 87% of the graft surfaces were already covered by bone at this time. Both values were significantly higher for autografts than for the 4 alternative bone fillers (P < or = 0.05). At 12 weeks, these differences were no longer apparent, with all 5 filling materials showing similar values. Among the tested bone substitutes, tricalcium phosphate (TCP) showed a significantly higher percentage of bone fill at 24 weeks of healing. It can be concluded that sites filled with autografts clearly demonstrated the best results underneath barrier membranes in the early phase of healing. As far as degradation and substitution are concerned, TCP showed the most promising results. This filler, however, needs to be tested further in a more demanding animal model. Less favorable results were obtained for coral-derived hydroxyapatite granules and for demineralized freeze-dried bone allografts.     

Effect of Tisseel on healing after periodontal flap surgery.

The purpose of this investigation was to evaluate the effect on healing of fast and slow absorbable Tisseel in combination with periodontal flap surgery. Mucoperiosteal flaps were raised on the buccal aspect of maxillary premolars and mandibular premolars and first molars in 4 beagle dogs. The underlying buccal, interproximal and inter-radicular bone was then removed to a level of approximately 5 mm apically to the original bone crest and half way into the interdental spaces and bifurcations. The exposed root surfaces were curetted in order to remove the periodontal ligament tissue, and a notch was made in the root surface at the base of the defects. On the control teeth, the flaps were sutured immediately after creation of the defects, while on the test teeth, a layer of fast (group I) or slow (group II) absorbable Tisseel was applied between the curetted roots and the subsurface of the flaps prior to suturing. Postoperatively, the teeth were brushed 2 x weekly. The dogs were sacrificed after 4 months. Histological analysis revealed that the amounts of new attachment and bone regrowth were similar in the test and control groups, although the results tended to be most favorable for the group of teeth treated with fast absorbable Tisseel (Group I).     

Differential effect of taurine and serotonin on the outgrowth from explants or isolated cells of the retina

The sulfur amino acid taurine and the indoleamine serotonin increases and decreases, respectively, the outgrowth from goldfish retinal explants. Taurine seems to be acting, at least partially, through an increase in calcium fluxes, and the serotonin-inhibiting effect appears to be mediated by serotonin_1A receptors and cAMP. Isolated cells of postcrush goldfish retina and of retina from 5-day-old rats were cultured in the presence of taurine or serotonin. In the goldfish, the classical morphology of postcrush ganglion cells was observed. An antibody against the glycoprotein Thy-1 labelled three types of cells in the cultures of goldfish retina. The number of cells outgrowing and the length of the main neurite was measured at 5 days in culture in both species. The number of cells presenting neurites was increased in the goldfish retina by the addition of taurine, and decreased by serotonin. However, the length of the neurites was unaffected by the addition of the modulators. In the rat, only a slight decrease in the number of cells outgrowing was observed in the presence of serotonin. The incorporation of [³H]thymidinewas not modified after 5 days in culture in the presence of taurine or serotonin, either in the goldfish or in the rat retina. The antibody Thy 1.1 can label retinal cells of the goldfish invitro, one of them being ganglion cells. The trophic effect exerted by taurine in the postcrush goldfish retina needs the integrity of the tissue favoring the interaction of cells and factors, because outgrowth increases in retinal explants, but not in isolated cells.     

NGD及NRF对大鼠坐骨神经缺损修复的电生理学检测

目的 :观察神经生长液 ( NGD)及神经再生素 ( NRF)修复大鼠坐骨神经缺损的效果。方法 :用生理盐水( NS)、NRF桥接以及 NRF桥接 +口服 NGD修复大鼠坐骨神经缺损 ,术后 12周检测大鼠坐骨神经干动作电位传导速度及肌电图。结果 :行为方面 NGD+ NRF组比 NS组恢复早 ,NS组、NRF组、NRF+ NGD组神经干动作电位传导速度的平均值分别为 5 .72 0 m/ s、16 .5 14 m/ s、2 1.310 m/ s。NS组与 NGD+ NRF组的神经干动作电位传导速度经统计学分析有显著性差异 ( P<0 .0 1)。NGD+ NRF组与 NS组的肌电图比较 ,前者的潜伏期短、峰谷值大、运动神经传导速度快。结论 :NGD+ NRF具有良好促进神经再生作用     

Repair and reconstruction of peripheral nerve injuries

Axonal regeneration after transection is a complex biological process. It is not merely a process of tissue repair, but rather of cellular repair of a large number of nerve cells. Regeneration involves restoration of the original morphology of each single cell, rather than proliferation. Techniques in microneurosurgical reconstruction of peripheral nerve injuries have improved over the last two decades, with subsequent improvement in functional results. Nerve autografts are now routinely used to guide the regrowth of the proximal nerves to distal nerve segments. However, the limited source of expendable cutaneous nerves restricts the use of nerve grafting techniques and is associated with significant morbidity. With extensive injuries there is an insufficient quantity of nerve autograft material to facilitate optimal repair. In future, the use of artificial conduits or nerve allografts could provide a limitless source of material to reconstruct otherwise irreparable traumatic nerve injuries. Establishment of appropriate strategies to suppress host-immune reaction or donor antigenicity would facilitate clinical allogeneic nerve transplantation. Guest lecture presented at the 69th Annual Meeting of the Japanese Orthopaedic Association in Tokyo on April 13, 1996.     

Effect of experimental alcoholism on structure and regenerative powers of the neonatal myocardium and liver of the next generation of newborn rats

Department of Pathological Anatomy, I. N. Ul'yanov Chuvash University, Nizhnii Novgorod. (Presented by Academician of the Academy of Medical Sciences of the USSR D. S. Sarkisov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 112, No. 11, pp. 552–553, November, 1991.     

复方红芪减方对周围神经再生影响的实验研究

目的　研究复方红芪提取液进行减方后对周围神经再生的作用。方法　建立钳夹损伤大鼠双侧坐骨神经的动物模型。按术后每日灌服药物的不同将 40只SD雄性大鼠随机均分为 4组。对照组 :灌服生理盐水 ;复方红芪组 :灌服复方红芪提取液 2ml ;减方组 :灌服复方红芪减方后提取液 2ml;补阳还五汤组 :灌服补阳还五汤 2ml。术后 2周及 4周 ,观察坐骨神经功能指数、运动神经传导速度及单位视野有髓神经纤维计数。结果　坐骨神经功能指数 :红芪组和减方组与对照组、红芪组与减方组的差异均有显著意义 (P >0 .0 5 ) ,且减方组优于红芪组 (P >0 .0 5 )。有髓神经纤维计数 :复方红芪组优于对照组 (P<0 0 1) ,减方组明显优于对照组 (P <0 .0 1) ,而红芪组与减方组间无显著差异。运动神经传导速度 :红芪组、减方组、补阳还五汤组与对照组相比 ,均优于对照组 (P <0 .0 5 ) ,但前 3组间无明显差异。结论　复方红芪减方提取液早期可以促进周围神经再生 ,药效更为专一 ,且优于传统方剂补阳还五汤。     

c-met和PCNA在肝再生动物模型肝脏细胞中的表达及其意义

①目的　探讨肝再生动物模型中肝细胞c met蛋白和PCNA的表达及其意义。②方法　建立肝再生动物模型 ,采用免疫组织化学方法 ,检测肝脏细胞中PCNA和c met蛋白的表达 ,并与对照组进行比较。③结果肝再生组PCNA表达较对照组增强 (uc=3.77,P <0 .0 5 ) ,c met表达与对照组比较 ,差异无显著性 (uc=0 .0 2 ,P >0 .0 5 )。肝再生组中c met蛋白在肝部分切除术后 12h表达降低 ,于术后 3d降到最低值 ,后逐渐上升 ,7d恢复正常 ;而PC NA表达于术后 1d开始增加 ,术后 3d达到最高峰 ,7d后降至正常 ,差异均有显著性 (Hc=17.3～ 19.4 ,P <0 .0 5 )。④结论　PCNA在肝脏中的表达提示肝脏切除后 ,剩余肝脏可迅速再生。检测c met的表达有助了解肝脏再生的规律。     

视神经半损伤后复合神经营养因子辅助再生的动态PVEP研究

目的：探讨视神经（optic nerve,ON）损伤后的自然修复再生和用脑源性神经营养因子（BDNF）及睫状神经营养因子（CNTF）互补辅助再生的图形翻转视觉诱发电位（PVEP）变化特征，寻找ON有效再生的新途径。方法：将40只猫作为实验对象，术前随机平均分4组：正常对照组，球后ON半径切断组（ON1／2I）、ON半径切断并定时向玻璃体内玻璃体内注射BDNF和CNTF复合因子辅助再生组（ON1／2I＋BF）。经眶外侧入路行手术开眶，在球后5mm处测量ON直径数值，并用宝石卡尺刀行ON半径切断术。ON1／2I＋BF组在术后即日注射BDNF和CNTF复合液（10ng），并在以后注射等量BDNF和CNTF复合液，2次／w。在ON损伤后1个月、4个月和8个月，3次行PVEP动态检测，结果：在ON1／2损伤后1个月时，与N组相比，ON1／2损伤各组PVEP的N1－P1振幅显著降低和P1潜时延迟；ON1／2IT ON1／2I＋PS组与ON1／2I＋BF组比较，也出现了PVEP的N1－P1振幅降低和P1潜时的延迟。在ON1／2损伤后第4个月时，ON1／2I组和ON1／2I＋PS与N组比较，其PVEP的P1潜时显著延迟（P＜0．001，P＜0．001）和N1－P1幅度显著降低（P＜0．001，P＜0．001）。而ON1／2I＋BF组与N组比较，两者PVEP的P1潜时和N1－P1幅度差异虽然具有显著性（P＜0．05），但与ON损伤后1个月时同组动物的PVPEP测试结果比较，已开始出现恢复型曲线图谱，两者的差异亦有显著性（P＜0．05，P＜0．01）。在ON1／2损伤后8个月后，ON1／2I组和ON1／2I＋PS组的PVEP的P1潜时仍然显著延迟，N1－P1幅度仍然显著降低，未见明显的恢复型曲线图出现。而ON1／2I＋BF组PVEP的P1潜时和N1－P1幅度与ON损伤后4个月时的PVEP测试结果比较，差异却具有显著性（P＜0．01）；与ON1／2切断组和ON1／2I＋PS组比较，差异也具有显著性（P＜0．01），与N组比较，其PVEP的P1潜时未见延迟（P＞0．05），但N1－P1幅度仍低于正常对照组（P＜0．05）。结论：（1）视神经1／2损伤后可以添加条件因素辅助其再生，BDNF和CNTF对促进视神经损伤后的再生有调节局部微环境和互补促生长作用。（2）视神经1／2损伤前后，其有视觉电生理学的动态变化特征，主要表现为：在ON损伤后，PVEP的P1潜时重度延迟和N1－P1波幅值大幅度衰减，而当应用神经营养因子拮抗视神经损伤效应后的1个月、4个月和8个月时，则逐渐出现PVEP的P1潜时恢复和N1－P1波幅值的提高。这说明1／2损伤的ON在BDNF和CNTF的互补作用下，可以修复再生和恢复其视觉信息的传导功能。BDNF和CNTF对促进视神经损伤后的轴突再生有互补促生长作用。