N-甲基亚硝基脲的制备及其诱发膀胱肿瘤的作用

目的 研究Ｎ－甲基亚硝基脲（ＭＮＵ）制备方法及其诱发大白鼠膀胱肿瘤的作用。方法 由甲胺盐酸盐合成诱癌剂ＭＮＵ,进行大白鼠膀胱灌注２ｍｇ／次,每２周１次,共４次,以光镜、扫描电镜、透射电镜等为观察手段,对其诱发的膀胱肿瘤进行观察。结果 ８周诱发膀胱肿瘤率为１００％,其组织学检查及病理学特征与人膀胱肿瘤十分相似。结论 自制的ＭＮＵ诱发的大白鼠膀胱肿瘤为比较理想的动物模型。     

Spermatic granulomata are experimentally induced in epididymides of mice receiving high-dose testosterone implants. I. A light-microscopical study.

It is known that a spermatic granuloma is induced by the inflammatory reaction following leakage of spermatozoa outside the germ cell ducts and is the main clinical complication of vasectomy. In the present study, we found that spermatic granulomata were experimentally induced in the epididymides of mice treated with high-dose testosterone. Testosterone powder (0.02, 0.2, or 2 mg per gram body weight) was implanted into ICR male mice, which were then killed from 7 to 63 days after the treatment for histological examination at the light-microscopic level. The results showed that the testis exhibited little or no degenerative change; however, the epididymides were frequently affected by spermatic granulomata after day 35 in mice implanted with high-dose testosterone (2 but not 0.2 or 0.02 mg per gram body weight). Observation of the early histological changes revealed that the ductal epithelium of the epididymides became vacuolated around day 25. Thereafter, the basement membrane of the epididymal ducts was ruptured after day 30, followed by leakage of spermatozoa into the adjacent interstitial tissue. The extravasated spermatozoa were then surrounded by macrophages (= epithelioid cells) and lymphocytes, resulting in the formation of a spermatic granuloma. In contrast, other mice treated with the same dose of deoxycorticosterone or estradiol did not show the induction of spermatic granulomata. Therefore, this study demonstrated that a spermatic granuloma is specifically formed in the epididymis by testosterone and that the lesion is started by vacuolation of the epididymal duct epithelium.     

两种构建大鼠膀胱癌模型方法的比较研究

目的:通过N-正丁基-N-(4-羟基-丁基)亚硝胺[N-butly-N-(4-hydroxybutyl)nitrosamine,BBN](BBN)喂饲和MNU膀胱灌注方法构建大鼠膀胱癌模型,比较两种实验方法的优缺点.方法:BBN诱癌组大鼠使用0.05% BBN溶液连续喂养六周.后改用2%枸橼酸钠溶液作后续喂养22周,第28周为诱导的终点.MNU诱癌组大鼠行MNU膀胱灌注,每两周灌药1次,每次2 mg/只.共4次.第10周为诱导的终点.比较两组大鼠的成瘤率和死亡率.结果:BBN诱癌组30只大鼠喂养28周后存活16只,11只成瘤,死亡率46.7%,存活大鼠成瘤率68.8%;MNU诱癌组30只大鼠第10周存活28只,25只成瘤,死亡率6.7%,存活大鼠成瘤率89.3%.结论:利用MNU行大鼠膀胱灌注的方法构建大鼠膀胱癌模型,具有成瘤时间短、成瘤率高、大鼠死亡率低等特点,优于BBN喂饲大鼠成瘤的方法.     

Changes in serum and prostatic zinc concentrations in rats after intraprostatic injection of zinc: Comparison of two forms of zinc delivery.

BACKGROUND: We investigated changes in zinc concentrations in serum and prostatic tissue after an intraprostatic injection of zinc, and compared two forms of zinc delivery: solution and liposome. METHODS: Ninety-six male Wistar rats were used in the study (24 controls, 72 test rats). The test animals were randomly divided into two groups and were injected intraprostatically with 2 mL of 0.04 mol/L zinc sulfate according to the form of zinc delivery. Nine rats in each test group were sacrificed 1 day, 7, 14 and 28 days after injection, and 24 normal rats were injected intraprostatically with 2 mL of distilled water as controls. Serum and prostatic zinc concentrations of each group were measured by inductively coupled plasma atomic emission spectrometry. Blood chemistries, routine urinalysis, urine culture and histopathologic examination were also performed. RESULTS: Serum zinc concentrations did not change significantly after the intraprostatic injection of zinc. Prostatic zinc concentrations were found to be significantly greater (P < 0.05) in zinc-injected groups than in the control group. The intraprostatic injection of zinc solution and zinc liposome increased zinc levels in both ventral and dorsolateral lobes significantly. Prostatic zinc levels increased progressively following injection, reaching a peak level in 7 days and maintaining a high value throughout the experimental period. The prostatic zinc level of the 1-day zinc liposome group was higher than that of the 1-day zinc solution group, while no significant difference was observed between the solution and liposome group in 7, 14, 28 days. No abnormal findings were observed in any of the laboratory and histopathologic examinations; however, an acute inflammatory response was observed in the 1-day groups. CONCLUSION: These findings suggest that an intraprostatic injection of zinc in normal rats increases and maintains the prostatic zinc level for at least 4 weeks without causing any systemic or local toxicities. These findings suggest the potentially important clinical applicability of local zinc to the treatment of chronic prostatitis.     

静脉注射内毒素法制作大鼠肠道细菌易位模型

目的探讨静脉注射内毒素制作大鼠肠道细菌易位模型的方法。方法60只雄性SD大鼠(体重200～250g)随机分为4组(15只/组)。其中3组为实验组,按组别不同分别给予尾静脉注射内毒素2、4、6mg/kg;对照组给予尾静脉注射生理盐水0.5ml。观察各组大鼠的体温、呼吸频率、外周血白细胞计数及死亡率,7d后将各组大鼠分别开腹取门静脉血、下腔静脉血、肠系膜淋巴结、肝、脾和胰腺组织作细菌培养。结果注射内毒素后各组大鼠的体温、呼吸频率及外周血白细胞均有不同程度的升高。2mg/kg组大鼠无死亡,组织细菌培养阳性率为24.4%。4mg/kg组的死亡率为20.0%,细菌培养阳性率为47.2%,其中肠系膜淋巴结阳性率为83.3%。6mg/kg组的死亡率为46.7%,细菌培养阳性率为64.6%,其中肠系膜淋巴结阳性率为100.0%。结论4mg/kg剂量的内毒素静脉注射是制作大鼠肠道细菌易位模型的较为理想可行的方法。     

A severe diabetic nephropathy model with early development of nodule-like lesions induced by megsin overexpression in RAGE/iNOS transgenic mice

Many factors are involved in the pathogenesis of diabetic nephropathy. A single gene abnormality may be prerequisite but insufficient to the disease to manifest. It is therefore only when a second or sometimes a third damage is associated that the consequences of pathogenic phenotypes become evident. We generated the triple transgenic mice overexpressing megsin (a novel glomerular-specific serpin), a receptor for advanced glycation end products (RAGE), and inducible nitric oxide synthase (iNOS). Compared with the single- or two-gene transgenic mice, the triple transgenic mice developed, at an early age (16 weeks), severe albuminuria and renal damage with all of the characteristics of human diabetic nephropathy (i.e., glomerular hypertrophy, diffuse mesangial expansion, inflammatory cell infiltration, and interstitial fibrosis). Interestingly, 30-40% of glomeruli exhibit nodule-like lesions. Oxidative and carbonyl stress makers (pentosidine, N(epsilon)-carboxymethyllysine, and 8-hydroxy-deoxyguanosine) were significantly higher in the triple transgenic mice. The iNOS transgenic mice have a diabetes phenotype, the renal consequences of which are moot, and the superimposition of RAGE leads to more conspicuous manifestations. By additional overexpression of megsin, a gene known to be involved in mesangial proliferation and expansion, these local consequences become dramatically manifest and approximate those observed in human pathology. This multiple hit approach is of interest in consideration of the sequential events during development of diabetic nephropathy.     

Use of an isolated joint model to detect early changes induced by intra-articular injection of paclitaxel-impregnated polymeric microspheres.

Paclitaxel is a chemotherapeutic agent that suppresses cellular proliferation and angiogenesis and has been effective in suppressing proliferative synovitis in animal models. Local joint delivery ofpaclitaxel is being pursued as a treatment for rheumatoid arthritis in humans, to avoid systematic toxicity of the drug. We used an extracorporeal, isolated metacarpophalangeal joint preparation that uniquely permitted the simultaneous evaluation of codependent hemodynamic, microvascular, and transsynovial flow responses of a joint. Specifically in this study, the isolated joint preparation provided quantitative assessment of vascular flow, transsynovial flow, and morphologic changes in response to intraarticular injection of paclitaxel (50 ng) in poly-(DL)-lactide co-glycolide 50:50 microspheres (50 microm diameter) to assess initial intra-articular biocompatibility. Control joints were isolated but not injected. Serial hemodynamic measurements, transsynovial fluid forces, synovial fluid analysis, synovial and capillary permeability, and oxygen metabolism were measured every 30 min during a subsequent 3-h isolation period. At termination, synovium and cartilage were harvested from bilateral metacarpophalangeal joints for histopathologic assessment. Intra-articular injection of this formulation of paclitaxel did not significantly affect hemodynamic parameters in the joint during this short-term study, and early joint inflammatory reaction was minimal. However, transsynovial fluid forces were significantly greater in treated joints as evidenced by greater synovial fluid flow, intra-articular pressure, transitional microvascular pressure, and permeability to fluid transport. Gross and histologic morphology of synovium and articular cartilage were normal in all isolated joints. In conclusion, this extracorporeal in vivo isolated joint model permitted investigation of the early changes in joint physiology induced by this microsphere formulation and dose ofpaclitaxel in joints and could provide a more physiologic and dynamic model for study of the pharmacokinetics of drug absorption following intra-articular administration. Due to the minimal inflammation and lack of evidence of gross or histologic change in the joint, this formulation of paclitaxel should be adequately biocompatible for use in an in vivo animal model for further study of its feasibility for human use.     

Quantitative （stereological） study of incomplete spermatogenic suppression induced by testosterone undecanoate injection in rats

Aim: To evaluate the key lesions in spermatogenesis suppressed partially by testosterone undecanoate(TU) treatment. Methods: Adult male SD rats were treated with vehicle or TU (19 mg/kg) injection (i.m.) every 15 days for 130 days. The numbers of all types of cells (nuclei) in the seminiferous tubules and the interstitial tissue were estimated using a contemporary stereological tool, the optical disector. Results: In response to TU treatment, the numbers of non-type B spermatogonia, type B sperrnatogonia and late elongated spermatids per testis were reduced to 51%, 66% and 14% of the controls, respectively. The conversion ratios from type B spermatogonia to early spermatocytes and pachytene spermatocytes were not significantly affected and the ratios to the later germ cell types fell to 51%-65% of the controls. Less than 1.0 % of immature round spermatids were seen sloughing into the tubule lumen, 4.0% of elongated spermatids retained in the seminiferous epithelium, and about half of the elongated spermatid nuclei appreciably malformed. Leydig cells were atrophied but their number and the peritubular myoid cell number per testis were unchanged. Conclusion: Double inhibition of spermatogenesis (i.e. inhibition at spermiation and spermatogonial conversion to type B spermatogonia), a scenario seen in the monkey and human following gonadotrophin withdrawal, was not sufficiently effective for a complete spermatogenic suppression in the rat after TU treatment, probably due to ineffective inhibition of the Leydig cell population and therefore the intra-testicular test-osterone levels. (Asian J Androl 2004 Dec; 6: 291-297)