Morphometric Studies of Pituitary Glands and Testes in Rats with Streptozotocin-Induced Diabetes

Morphometrische Untersuchungen von Hypophysen und Hoden bei Ratten mit Streptozotocin-induziertem Diabetes Beim Tiermodell für Diabetes mellitus sind Hodenveränderungen und gestörte Fruchtbarkeit seit vielen Jahren bekannt. Doch hat sich bei diabetischem Hypogonadisms das Interesse erst in letzter Zeit auf das hypothalamo-hypophysäre System konzentriert. Bei Streptozotocin-diabetischen Ratten beschrieben wir kürzlich morphologische und immunohistochemische Veränderungen im Nucleus arcuatus und in der Eminentia mediana, welche von Hypophysen- und Hodenveränderungen begleitet waren. In der vorliegenden morphometrischen Arbeit werden die zeitliche Entwicklung von hypophysären und testikulären Läsionen untersucht und mögliche Korrelationen zwischen klinischen Werten und morphologischen Veränderungen geprüft. Bei Wistarratten wurden nach 4, 8 und 12 Monaten Streptozotocin-Diabetes Blutglukose, Körper- und Hodengewicht, Querschnittsfläche der Hodentubuli und Zahl der LH-Gonadotrophen in der Hypophyse untersucht. Bei den Diabetikern war das Hodengewicht nach 4 und 12 Monaten deutlich erniedrigt, nach 8 und 12 Monaten auch die Tubulusfläche signifikant kleiner. Bei 20–25% der Tiere traten die Hodenveränderungen früh auf (nach 4 Monaten oder früher), Tubulusflächen waren stark verkleinert, mit einem (sub-) totalen Block der Spermatogenese. Bei den übrigen Tieren erschienen die Veränderungen geringgradiger und traten später auf (nach 8–12 Monaten). Die Leydigzellen waren vermindert, verkleinert und oft degeneriert; die LH-Gonadotrophen stark vermehrt. Dabei handelte es sich vorwiegend um kleine atypische Zellen. Zwischen Körper- und Hodengewicht bestand eine positive, zwischen Tubulusflächen und LH-Gonadotrophen eine negative Korrelation. Diese Befunde bestätigen die pathogenetische Bedeutung der Läsionen im hypothalamo-hypophysären System bei diabetischem Hypogonadismus, wie er bei Streptozotocin-diabetischen Ratten auftritt. Zudem lassen die Befunde einen zweiphasigen Mechanismus dieser diabetischen testikulären Veränderungen vermuten.     

患糖尿病12周大鼠睾丸生精细胞周期及其凋亡与抗氧化水平的变化

目的:探讨患糖尿病12周大鼠睾丸生精细胞周期及其凋亡和血清与睾丸抗氧化水平的变化。方法:W istar大鼠随机分为正常对照组10只,糖尿病组20只。腹腔注射链佐脲菌素(STZ)建立糖尿病大鼠模型,12周末记录其存活率、体重和睾丸重量;采用流式细胞术检测生精细胞周期各时相细胞百分率和细胞凋亡率,应用硫代巴比妥酸法(TBAR s)、硝酸还原酶法、黄嘌呤氧化酶法、二硫代二硝基苯甲酸法(DTNB)和分光光度法分别检测血清及睾丸丙二醛(MDA)和一氧化氮(NO)含量,超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)和NO合酶(NOS)活性。结果:大鼠患糖尿病12周后,其存活率、体重和睾丸重量显著低于正常对照组(P<0.05);G0/G1期生精细胞显著增加(P<0.05),S期和G2/M期细胞减少,即发生了G0/G1期细胞阻滞;生精细胞凋亡率明显增加(P<0.05)。与正常对照组相比,糖尿病大鼠血清和睾丸MDA含量增加,其中后者增加明显(P<0.01);血清及睾丸SOD活性降低;血清GSH-Px活性显著低于对照组(P<0.05),而睾丸GSH-Px活性显著增高(P<0.01);血清和睾丸NO含量增高,尤其前者显著升高(P<0.01);血清NOS活性显著降低(P<0.05)。结论:睾丸组织及血清MDA和NO含量增加,以及抗氧化酶活性降低,可能与糖尿病大鼠生精细胞G0/G1期阻滞和凋亡增多所致生精障碍有关。     

Effect of Estradiol Benzoate on the Pituitary-Gonadal Axis in the Intact Male Rat

Adult male rats were treated with 50 microgram of estradiol benzoate daily for 28 days. The sex organs and pituitary weights showed changes classically associated with estrogen treatment. Both plasma and testicular testosterone levels diminished to almost trace level 24 hours after the first estrogen injection and remained at that level throughout the experimental period. The pituitary LH levels and concentration showed a progressive decline; however, the plasma LH levels remained unchanged throught the experimental period. These findings suggest that in intact adult males, estrogen affects testicular testosterone production directly. These observation suggests the necessity for reevaluation of the current concepts concerned with testis-pituitary feedback mechanisms.     

糖尿病雄性大鼠骨代谢特点的观察

目的观察Ⅰ型糖尿病雄性大鼠骨代谢的特点以及骨密度和骨组织形态计量学指标的变化。方法采用高糖高脂饮食加腹腔注射小剂量链脲佐菌素诱导建立Ⅱ型糖尿病大鼠模型。20周后处死大鼠,测定股骨和腰椎骨密度、骨形态计量学以及骨代谢相关指标（血清骨钙素、抗酒石酸酸性磷酸酶、24h尿Ca、24h尿羟脯氨酸）,此外还观察了GHbAlc、胆固醇、低密度脂蛋白-胆固醇、胰岛素样生长因子-1等变化。结果Ⅱ型糖尿病大鼠血清骨钙素、股骨和腰椎骨密度以及骨形态计量学指标反映骨形成参数均明显低于正常对照组,而血抗酒石酸酸性磷酸酶活性和尿钙、尿羟脯氨酸排出量以及形态计量学反映骨吸收参数均明显高于正常大鼠。结论Ⅱ型糖尿病大鼠的骨吸收加快丽骨形成不足。导致其骨量下降和骨形态计量学特性改变。     

Diabetes mellitus alters the mechanical properties of the native tendon in an experimental rat model

The purpose of this study was to determine the effect of the diabetic phenotype on the mechanical properties of the native patellar tendon and its enthesis. Diabetes was induced via intraperitoneal injection of streptozotocin in Lewis rats. Control (n = 18) and diabetic animals (n = 20) were killed at 12 and 19 days for analysis. Statistical comparisons were performed using Student's t‐tests and a two‐tailed Fisher test with significance set at p < 0.05. Pre‐ and post‐injection intraperitoneal glucose tolerance tests demonstrated significant impairment of glycemic control in the diabetic compared to control animals (p = 0.001). Mean serum hemoglobin A1c levels at 19 days was 10.6 ± 2.7% and 6.0 ± 1.0% for the diabetic and control groups, respectively (p = 0.0001). Fifteen of sixteen diabetic animals demonstrated intrasubstance failure of the patellar tendon, while only 7 of 14 control specimens failed within the tendon substance. The Young's modulus of the diabetic tendon was significantly lower than control specimens by 19 days post‐induction (161 ± 10 N m^?2 compared to 200 ± 46 N m^?2, respectively) (p = 0.02). The metabolic condition of poorly controlled diabetes negatively affects the mechanical properties of the native patellar tendon. These altered structural properties may predispose diabetic patients to a greater risk of tendinopathy and/or traumatic rupture. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29:880–885     

镇痛灵对雄性1型糖尿病大鼠性功能的影响

目的 :本实验以成年雄性大鼠为研究对象 ,观察和探讨中药镇痛灵对糖尿病大鼠性功能的影响。　方法 :3～ 5月龄雄性Wistar大鼠 32只 ,随机分为糖尿病组 2 2只 ,正常对照组 10只。 72h后 ,将造模成功的糖尿病大鼠随机分为 2组 :未治疗组 ;镇痛灵治疗组。第 5周测血糖 ,阿朴吗啡勃起实验后 ,乙醚麻醉下断头取血 ,分离血清 ,取一侧睾丸组织制成匀浆液 ,测定血清及组织匀浆中NO及NOS水平。　结果 :糖尿病大鼠与正常对照组比较 ,血清NO、NOS明显降低 ,差异有高度显著性 (P <0 .0 0 1) ;镇痛灵治疗组血清NO、NOS值与未治疗组比较明显升高 ,差异有显著性 (P <0 .0 1) ;阿朴吗啡勃起实验证实 ,镇痛灵治疗组大鼠阴茎勃起次数明显多于未治疗组 ,差异有显著性(P <0 .0 1) ,而与正常对照组比较 ,差异无显著性 (P >0 .0 5 )。　结论 :复方中药合剂镇痛灵有降血糖作用 ,对糖尿病并发的性功能障碍有一定治疗作用。     

Effect of Streptozotocin-Induced Diabetes on Insulin Binding Parameters in Adult Rat Testis

Summary:  Insulin binding parameters have been measured in testicular membranes of streptozotocin diabetic male rats. Insulin binding decrease was ascribed to the well-known depressing effect of diabetes mellitus on circulating luteinizing hormone (LH). Because both LH and insulin receptors are modulated by pituitary LH and because of their reduction in testes of diabetic rats, we conclude that Leydig cell dysfunction is a secondary disorder associated with this complex metabolic condition.
Zusammenfassung:  An den testikulären Membranen von männlichen Ratten wurden Insulinbindungsparameter untersucht, die mittels Streptozotocin in eine diabetische Stoffwechsellage gebracht worden waren. Die Verminderung der Insulinbindungskapazität wurde dem negativen Effekt des zirkulierenden LH auf den Diabetes mellitus zugeschrieben. Sowohl die LH- als auch die Insulinrezeptoren werden durch hypophysäres LH moduliert. Aus der Verringerung dieser Rezeptoren im Hoden der diabetischen Ratte wurde geschlossen, daß die Leydigzell-Insuffizienz ein sekundäres Pänomen dieser komplexen Stoffwechselstörung ist.     

糖尿病大鼠阴茎细胞凋亡及血流动力学变化的研究

目的 :比较糖尿病和健康大鼠阴茎细胞凋亡及血流动力学的变化。　方法 :16只糖尿病 (糖尿病组 )和 10只健康Wistar大鼠 (对照组 ) ,注射链脲佐菌素 (STZ ,6 5mg/kg) ,建立糖尿病模型。 8周后处死大鼠 ,测糖化血红蛋白(HbA1c)并取阴茎组织。用原位缺口末端标记 (TUNEL)法和流式细胞术分析阴茎细胞凋亡 ,并测量阴茎动脉血管管径和管壁厚度。　结果 :糖尿病组出现阴茎海绵体细胞凋亡 ,与对照组比较差异有显著性 (P <0 .0 1)。流式细胞术分析糖尿病组大鼠出现凋亡峰 ,与对照组相比差异有显著性 (P <0 .0 5 )。糖尿病组阴茎动脉血管管径变小 ,管壁增厚 ,与照组相比较差异有显著性 (P <0 .0 5 )。　结论 :糖尿病可引起大鼠阴茎细胞凋亡增加 ,导致阴茎动脉的管径变小和动脉的管壁增厚。     

Age at Onset of Type 1 Diabetes in Parents and Recurrence Risk in Offspring

OBJECTIVE

Our aim was to study the recurrence risk of type 1 diabetes in the offspring of parents with adult-onset (15–39 years) type 1 diabetes and to evaluate the transmission of diabetes within a continuum of parental age at onset of diabetes from childhood to adulthood.

RESEARCH DESIGN AND METHODS

Diabetes status of all offspring (n = 9,636) in two Finnish cohorts of parents with type 1 diabetes was defined until the end of year 2007. Cumulative incidences of type 1 diabetes among the offspring were estimated, and several factors contributing to the risk were assessed.

RESULTS

During 137,455 person-years, a total of 413 offspring were diagnosed with type 1 diabetes. The cumulative incidence by 20 years was 4.0% (95% CI 3.1–4.8) for the offspring of parents with adult-onset diabetes. The risk was equal according to the sex of the parents. The cumulative incidence decreased in parallel with the increase in age at onset of diabetes in the fathers. In the offspring of diabetic mothers, the risk was equal regardless of the age at onset of diabetes. However, the reduced risk in the maternal offspring was most pronounced in the daughters of the mothers with a diagnosis age <10 years.

CONCLUSIONS

Type 1 diabetes transmission ratio distortion is strongly related to the sex and age at onset of diabetes in the diabetic parents.Type 1 diabetes can occur at any age, although it is predominantly seen in children and young adults. Therefore, the majority of studies have been conducted in children aged <15 years. The recurrence risk in the offspring ranges from 3 to 6% depending on the study design, follow-up time, and the population where the study was conducted (1–3). Little is known about the recurrence risk in first-degree relatives of subjects diagnosed with type 1 diabetes, aged >15 years. The incidence of type 1 diabetes is much lower in young adults than in children (4–6). Consequently, the risk of family members may also be different among the diabetic subjects affected after childhood.Sex-related factors seem to be involved in the transmission of diabetes from one generation to the next (7). By 20 years of age, 5–8% of the offspring of diabetic men and only 2–5% of the offspring of diabetic women have been found to be affected (1–3,8). We have previously shown that the recurrence risk of diabetes in the offspring of parents diagnosed between 0–17 years of age was higher the younger the father was when diagnosed with type 1 diabetes. This pattern was not present in the offspring of the mothers (8). However, it is not known whether the sex-related factors play a role in the transmission of diabetes in adult-onset type 1 diabetes. We have now enlarged our study to also include the offspring of parents diagnosed with diabetes between 15 and 39 years of age. This gives us an opportunity to determine the risk in the offspring of parents with a broad age span at diagnosis and to elucidate whether there are differences in the risk between the offspring of diabetic mothers and fathers.     

Gonadotrophin Changes in Male Rats Following a Sterilizing Dose of α-Chlorohydrin

A single oral sterilizing dose of α-chlorohydrin (80 mg/kg) produced obstructive retention cysts in the caput epididymis and ductuli efferentes of the male rat with resultant destruction of the spermatogenic epithelium. The weights of androgen dependent organs other than the epididymidis were not changed by the treatment, suggesting that androgen secretion was not impaired. Serum prolactin was elevated for several weeks after α-chlorohydrin possibly correlated with a diuretic action. LH secretion was unchanged for 4 days, significantly elevated at 7 days, then slowly declined to normal, a result which could not be correlated with the other endocrine changes. Serum FSH was significantly elevated by day 4 and remained high for the period of the experiment. The results support the idea of separate controlling mechanisms for LH and FSH secretion. The rapid and persistent rise in FSH supports the view that a hormonal factor (inhibin) is normally produced by the seminiferous epithelium. The possibility that inhibin is normally absorbed via the epididymis and in these experiments fails to reach the systemic circulation because of the epididymal lesion is discussed.     

Mechanisms in the Production of Prepuberal Reproductive Defects in Neonatal Estrogenized Male Rats

Neonatal estrogenization induced in prepubertal males atrophy of the testis and ventral prostate and increased the weight of the seminal vesicles. Atrophy of the testis was probably due to the inhibition of FSH and LH secretion: males estrogenized on day one and sacrificed daily from day six to day fifteen showed lower gonadotropin levels than their respective controls. In addition, daily FSH and LH administration (80 micrograms/100 g BW and 40 micrograms/100 g BW respectively) from day one to day fifteen increased testicular development more effectively in estrogenized than in control males and the differences between the two groups disappeared. Prostate atrophy was due to the decreased testosterone secretion. The reason for the hypertrophy of the seminal vesicles remains unclear: reduction in Prolactin levels due to bromocriptine treatment did not normalize the seminal vesicles weight, indicating that hyperprolactinemia was not the cause. Male rats estrogenized on day one, orchidectomized on day 5 and decapitated on day fifteen also showed hypertrophy in their seminal vesicles. These results indicate that testicular factors, other than testosterone, were not responsible for the vesicular hypertrophy. It seem possible that estrogens might act directly on vesicular growth.     

成年糖尿病大鼠睾丸、附睾和前列腺内雄激素受体的表达研究

目的:观察糖尿病大鼠睾丸、附睾和前列腺内是否存在雄激素受体(AR)的异常表达。方法:用链脲菌素(STZ)诱导成年大鼠糖尿病模型,实验分正常对照组(C组)、糖尿病组(D组)及胰岛素治疗组(ID组),分别以Northern印迹及放射配基法检测睾丸、附睾和前列腺内AR的mRNA及蛋白质水平。结果:D和ID组血清睾酮水平低于C组(P<0.05);附睾内D和ID组AR的mRNA水平低于C组(P<0.05),睾丸和前列腺内D组AR的蛋白质水平低于C组(P<0.05)。结论:糖尿病大鼠睾丸、附睾和前列腺内AR的表达降低,从而削弱了雄激素的生物利用度,这可能是导致患病大鼠性与生殖功能障碍的原因之一。     

Changes in the Acetylcholinesterase Activity of Mammalian Spermatozoa during Maturation

Acetylcholinesterase (AChE) activity of sperm recovered from the testes and several epididymal sites was studied in the boar, bull, and rat. AChE was highest in the bull spermatozoa followed by those of the rat and the boar. Between the testis and caput epididymis washed spermatozoa lost about 86% (bull), 60% (boar) or 32% (rat) in AChE activity while between the caput and cauda epididymides, a further loss of 28, 10, and 27% in the enzyme activity occurred in the respective species. Sperm AChE activity was negatively related to the development of sperm motility during sperm maturation and with sperm abnormality.     

Involvement of Insulin and Testosterone in the Reproduction of Streptozotocin Diabetic Rats

Streptozotocin diabetic rats were shown to be subfertile, which can be overcome by treatment with insulin plus hCG. In this study, we have shown that replacement of hCG by exogenous testosterone was enough for restoration of the accessory glands activity in contrast to its failure to preserve sparmatogenesis and restore fertility. A synergistic effect of insulin and testosterone in control of the male accessory glands was evident. Exogenous testosterone, insulin or both together improved only slightly the epididymal function as reflected in sperm motility and fertility capacity. The fertility rate of the diabetic rats (14%) treated with either insulin (22%), testosterone (40%), or both together (50%) was not as good as the synergistic effect of insulin and hCG. These results point to the beneficial effect of LH (by hCG) in the regulation of male fertility apart from its control on the activity of the Leydig cell function.     

Occurrence of oxidative impairments, response of antioxidant defences and associated biochemical perturbations in male reproductive milieu in the Streptozotocin-diabetic rat

Oxidative stress is implicated to play a vital role in the pathogenesis of various diabetic complications. While reproductive dysfunction is a well recognized consequence of diabetes mellitus, the underlying mechanisms are poorly understood. The present study aims to obtain insights into the incidence, extent and progression of oxidative impairments in testis and epididymal sperm (ES) in streptozotocin (STZ)-induced diabetic rat during early and progressive phase. Adult rats (CFT-Wistar strain) rendered diabetic by an acute dose of STZ (60 mg/kg bw, i.p.) were examined for induction of hyperglycaemia at 72 h, followed by the assessment of oxidative impairments in testis and ES over a 6-week period. Oxidative damage was ascertained by measuring the malondialdehyde levels, reactive oxygen species (ROS) generation, alterations in antioxidant defences and extent of protein oxidation. STZ induced a significant (2.5-fold) increase in blood glucose levels. In diabetic rats, both testis and ES showed enhanced status of lipid peroxidation measured as increased TBARS and ROS from week 2 onwards. These impairments in testis were consistent, progressive and accompanied by marked alterations in antioxidant defences and elevated protein carbonyls. Varying degree of reduction in the specific activities of antioxidant enzymes was evident in testis and ES, while the activity of glutathione-S-transferase (GST) was significantly elevated. Reduced glutathione (GSH) and vitamin E levels were consistently reduced in testis. Lipid dysmetabolism measured in terms of increased cholesterol, triglycerides and phospholipids was evident only beyond week 2 in diabetic testis. Taken together, these results indicate that the testis and ES are indeed subjected to significant oxidative stress in the STZ-diabetic rat both during early as well as progressive phase. It is hypothesized that oxidative impairments in testis which develop over time may at least in part contribute towards the development of testicular dysfunction eventually leading to testicular degeneration which culminates in reduced fertility during the progressive phase of STZ-induced diabetes in adult rats.     

环氧合酶-2在成年雄性大鼠睾丸和附睾中的表达

目的:探讨环氧合酶 2在雄性大鼠睾丸和附睾组织中的表达及其意义。　方法:应用免疫组化SP法检测 40只雄性SD大鼠睾丸和附睾组织中环氧合酶 2的表达及其定位情况。　结果:环氧合酶 2在雄性大鼠的睾丸和 附睾组织中有较强的表达。在附睾头部主要表达于腔上皮细胞的细胞核内,部分细胞质内也可见表达,睾丸精原 细胞胞质和细胞核内均可见棕黄色颗粒。　结论:免疫组化法可较为敏感地检测环氧合酶 2在雄性大鼠睾丸和 附睾组织的表达。     

The Protective Effects of Ascorbic Acid against Renal Ischemia-Reperfusion Injury in Male Rats

There is increasing evidence to suggest that toxic oxygen radicals play an essential role in the pathogenesis of ischemia/reperfusion (I/R) injury in the kidney. This study was designed to investigate the effects of ascorbic acid (AA) in I/R-induced renal injury in rats. Thirty two male Sprague-Dawley rats were divided equally into four groups: group 1 (control; dissection of the right renal pedicle without nephrectomy), group 2 (sham operated; unilateral nephrectomy), group 3 (I/R; unilateral nephrectomy?+?I/R); and group 4 (AA+I/R; unilateral nephrectomy and I/R treated with ascorbic acid, 250mg kg^?1 i.p., for one hour prior to ischemia). On the 15th day following nephrectomy, groups 3 and 4 were subjected to 45 min of renal pedicle occlusion followed by 3 h of reperfusion. At the end of the treatment period, kidney samples were taken for histological examination or determination of the renal malondialdehyde (MDA) and glutathione (GSH) levels. Serum creatinine, blood urea nitrogen (BUN), and lactate dehydrogenase (LDH) concentrations were measured for the evaluation of renal function. I/R caused a significant decrease in GSH level, which was accompanied with a significant increase in MDA level of kidney tissues. Similarly, serum BUN and creatinine levels, as well as LDH, were elevated in the I/R group as compared to the control group. In group four, AA treatment reversed all the changes in these biochemical indices, as well as histopathological alterations normally induced by I/R. The findings imply that reactive oxygen species play a causal role in I/R-induced renal injury, and that AA exerts renoprotective effects, probably by radical scavenging and antioxidant activities.     

Development of the blood-testis barrier and changes in vascular permeability at puberty in rats

The effectiveness of the blood-testis barrier to water-soluble substances was assessed in rats of various ages by measuring the volumes of distribution of Cr-EDTA and albumin, and estimating the proportion of the testis made up by interstitial tissue and tubular lumen by morphometric techniques on cryostat sections of frozen tissue. The interstitial tissue volume fell from 15 days to reach adult values at about 30 days of age. A lumen was present in some animals at 15 days, and it enlarged progressively to reach adult levels at about 45 days of age. The 1-h Cr-EDTA space began to fall after 25 days, and reached adult values by 33 days; in rats aged 25 and 30 days, the Cr-EDTA space was almost twice the measured interstitial tissue volume, but even in the older rats, the Cr-EDTA space remained appreciably greater than the interstitial tissue volume. The 20-h albumin space did not begin to fall until after 33 days, and had still not reached adult values in rats aged 44 days. Thus, the functional barrier to water-soluble markers develops later and more gradually than the barrier to electron-opaque markers as used by previous authors, and its appearance correlates more closely with enlargement of the tubular lumen than with formation of the inter-Sertoli cell junctions. The rate at which the albumin space approached its final value was used to calculate the vascular permeability to albumin. This rose to a maximum between 25 days and 33 days of age, and then fell again, although adult values had still not been reached by 44 days of age.