Reproductive disorders in pubertal and adult phase of the male rats exposed to vinclozolin during puberty

Vinclozolin (VCZ) is a systemic dicarboximide fungicide with antiandrogenic activity. Reproductive toxicity of VCZ was investigated in male rats exposed to VCZ during puberty. Sprague-Dawley male rats aged with 35 days were assigned to six different groups; negative control, positive control receiving flutamide (100 mg/kg), VCZ (100, 200 and 400 mg/kg), and a combination of VCZ (200 mg/kg) + methyltestosterone (100 mg/kg). The animals were treated with test compounds by oral gavage daily during 35 to 44 days of age. In pubertal rats sacrificed on the next day after final treatment, VCZ or flutamide-treated group showed a decrease in weights of prostate, epididymis, and seminal vesicle, hypertrophy of Leydig cells in the testis, detached debris and sloughed cells in the tubules of the caput epididymis, and an increase in serum testosterone levels. On the other hand, combined treatment of VCZ + methyltestosterone decreased testicular weight, increased seminal vesicle weight, and induced degeneration of spermatocytes. In adult rats sacrificed at five weeks after final treatment, flutamide decreased testicular sperm counts, and VCZ, flutamide and VCZ + methyltestosterone also decreased epididymal sperm counts. In addition, treatment of VCZ (400 mg) or VCZ + methyltestosterone decreased some motion kinematic parameters of sperms including curvilinear velocity, mean angular displacement and lateral head displacement. Flutamide treatment also decreased lateral head displacement. These results indicate that VCZ exposure during pubertal period in male rats causes reproductive disorders in puberty and adulthood.     

Effect of iodine supplementation on thyroid and testicular morphology and function in euthyroid rats

Seventy-five male weaner euthyroid rats, randomly divided into three equal groups were used to evaluate the effect of iodine supplementation in the diet on growth and spermatogenesis. From the age of six weeks, the rat groups were fed normal diet containing 0.05 mg iodine/Kg diet (A); normal diet supplemented with 0.5 mg/Kg iodine (B) and normal diet supplemented with 3.0 mg/Kg iodine for a period of 90 days. Thereafter, all three groups were fed the normal diet for another 60 days. Body weight and feed consumption were determined; morphomeric studies of thyroid glands, testes and epididymes were carried out. Spermatogenesis was evaluated with epididymal (ESC) and testicular sperm counts (TSC). Increasing iodine intake significantly (p < 0.05) decreased mean body weight from day 30 of supplementation. Iodine supplementation influenced feed conversion ratio and efficiency in feed utilization in an inconsistent pattern. Supplementation did not significantly (p > 0.05) alter the size of thyroid glands, but increased the mean weights of the testes and epididymes to levels significantly (p < 0.05) higher than values for non-supplemented rats at specific stages of the study, especially at the highest (3 ppm) level of iodine supplementation. However, supplementation resulted generally in lower sperm counts, which was significant (p < 0.05) in the case of the epididymes. The results of the study show that iodine supplementation to weaner, non-iodine deficient euthyroid rats at 3ppm not only retard weight gain but could also reduce fertility by lowering epididymal sperm counts.     

Protective Effect of Sulforaphane on Reproductive Function of Male Mice with Cadmium Poisoning

The study was aimed to explore the protective effect of sulforaphane (SFN) on the reproductive function of male mice with cadmium poisoning.40 healthy clean grade male Kunming mice were randomly divided into four groups:control group (H₂O),cadmium chloride group (2.3 mg/kg CdCl₂),sulforaphane group (10 mg/kg SFN),sulforaphane + cadmium chloride group (10 mg/kg SFN+2.3 mg/kg CdCl₂),and continuous administration for 10 d,all mice were executed by dislocated cervical vertebra at 2 d after the last administration,and then the pathologic changes of testicular tissues,organ coefficient of testicle and epididymis,sperm quality and concentration of testosterone were tested.Additionally,the contents of GSH and MDA,and the activities of T-SOD in testis were also detected at the same time. Compared with the control group,pathology damages were observed in cadmium chloride group,organ coefficient of testis and epididymis,sperm quality and levels of testosterone extremely significantly decreased (P<0.01),the activities of T-SOD and GSH content were extremely significantly decreased (P<0.01),and the concentration of MDA was extremely significantly enhanced (P<0.01).Compared with the control group,the activity of T-SOD and concentration of GSH in sulforaphane group were significantly increased (P<0.05),and the concentration of MDA was not significant different between the control group and sulforaphane group (P>0.05).While compared with the cadmium chloride group,the sperm motility rate and sperm total count in sulforaphane and cadmium chloride group were extremely significantly increased (P<0.01),the organ coefficient of testicle and epididymis was increased significantly (P<0.05),the concentration of GSH and activity of T-SOD in testicular tissue were extremely significantly increased (P<0.01),and the concentration of MDA was extremely significantly decreased (P<0.01).The results indicated that sulforaphane had the protection effect on reproduction function of male mice with cadmium poisoning.     

玉米赤霉烯酮与脱氧雪腐镰刀菌烯醇联合染毒对雄性小鼠生殖毒性的影响及茶多酚的缓解作用

本试验旨在研究茶多酚对玉米赤霉烯酮(ZEN)与脱氧雪腐镰刀菌烯醇(DON)联合染毒小鼠生殖毒性损伤的缓解作用。选取8周龄雄性昆明小鼠75只[体重(40±5)g],随机分成5组,每组分别灌服生理盐水(对照组)、200 mg/kg茶多酚(Ⅰ组)、1 mg/kg ZEN+0.5 mg/kg DON(Ⅱ组)、100 mg/kg茶多酚+1 mg/kg ZEN+0.5 mg/kg DON(Ⅲ组)和200 mg/kg茶多酚+1 mg/kg ZEN+0.5 mg/kg DON(Ⅳ组),每组15只。试验期28 d。在试验第1、14、28天,从每组随机抽取5只小鼠称重采样,检测小鼠精子质量、睾丸脏器系数、睾丸组织标志酶活性、血清性激素含量及睾丸组织氧化与抗氧化指标,并制作睾丸组织切片。结果表明:1)与对照组相比,Ⅱ组小鼠睾丸脏器系数、精子活率及数量、血清性激素含量显著降低(P<0.05),睾丸组织碱性磷酸酶(AKP)、乳酸脱氢酶(LDH)、γ-谷氨酰转移酶(γ-GGT)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)及谷胱甘肽过氧化物酶(GSH-Px)活性显著降低(P<0.05);精子畸形率、血清丙二醛(MAD)含量显著上升(P<0.05)。添加茶多酚后,小鼠的睾丸脏器系数、精子活率及数量、血清性激素含量、睾丸组织AKP、LDH、γ-GGT、CAT、SOD及GSH-Px活性显著上升(P<0.05),精子畸形率、血清MAD含量显著降低(P<0.05)。随着时间的推移,与第1天相比,Ⅰ组小鼠睾丸组织GSH-Px活性显著升高(P<0.05),Ⅱ组小鼠睾丸脏器系数、精子质量、睾丸组织标志酶活性、血清性激素含量、睾丸组织氧化与抗氧化指标均发生显著变化(P<0.05),Ⅲ组小鼠睾丸组织CAT及GSH-Px活性显著降低(P<0.05),Ⅳ组小鼠睾丸组织CAT活性显著降低(P<0.05)。2)睾丸组织病理切片显示染毒组小鼠睾丸生精小管基膜不完整,细胞排列紊乱,数量减少,体积缩小,细胞之间空泡化,管腔内精子数量减少,经茶多酚保护后得到改善。综上,茶多酚能有效改善ZEN与DON联合染毒小鼠精子质量与睾丸组织内标志酶活性,提高血清性激素含量及睾丸组织抗氧化功能,显著降低生殖毒性。     

Dose-dependent Response to an Intratesticular Injection of Calcium Chloride for Induction of Chemosterilization in Adult Albino Rats

This study concerned the minimum and optimum effective doses of calcium chloride needed for induction of chemosterilization in male albino rats, 30 days after a single intratesticular injection of calcium chloride (CaCl₂.2H₂O) solution at 2.5, 5, 10 or 20 mg per 100 g body weight per testis. There was a significant diminution in the relative wet weight of the sex organs (p<0.01), epididymal sperm count (p<0.001), plasma concentration of testosterone (p<0.01), testicular activities of D,3-hydroxy steroid dehydrogenase (D,3-HSD), 17-hydroxy steroid dehydrogenase (17-HSD) (p<0.01), glutathione S-transferase (GST) (p<0.01), superoxide dismutase (SOD) (p<0.01), and peroxidase (p<0.01), significant elevations in testicular content of malondialdehyde (MDA) and conjugated dienes (p<0.01), along with derangement of seminiferous tubular architecture and degeneration of the Leydig cells in the testis and elevations in the concentrations in the plasma of LH and FSH (p<0.01), commencing at a dose of 5 mg, with the greatest effects at a dose of 20 mg. No significant alterations in these factors occurred at the dose of 2.5 mg in comparison to the control that received only the vehicle. There was no significant alteration in the plasma concentrations of prolactin (p>0.05), corticosterone (p>0.05) or fasting blood glucose or in the rectal temperature (p>0.05) at any of the doses relative to the control group, suggesting that this chemosterilizing procedure did not exert any chronic stress on the experimental animals. From these observations, it may be suggested that 5 mg should be considered as the minimum dose, and 10 mg or 20 mg as the optimum dose, whereas 2.5 mg was ineffective for induction of chemosterilization. There would seem to be little point in using more than 20 mg of calcium chloride for this purpose. Intratesticular injection of calcium chloride at an effective dose may be considered as an alternative to surgical castration.     

莱菔硫烷对镉中毒雄性小鼠生殖机能保护作用的研究

本试验旨在研究莱菔硫烷(SFN)对染镉雄性小鼠生殖机能的保护作用.选择健康的清洁级雄性昆明系小鼠40只,随机分成4组,分别为对照组(H₂O)、镉组(2.3 mg/kg CdCl₂)、莱菔硫烷组(10 mg/kg SFN)、镉+莱菔硫烷组(10 mg/kg SFN+2.3 mg/kg CdCl₂),连续给药10 d,于最后一次给药2 d后脱颈处死,检测小鼠睾丸组织病理学变化、小鼠睾丸及附睾的脏器系数、精液品质及血清睾酮浓度.同时检测睾丸组织内丙二醛(MDA)、谷胱甘肽(GSH)含量及总超氧化物歧化酶(T-SOD)活性的变化.结果表明,与对照组相比,镉组小鼠的睾丸组织发生病理学损伤,睾丸及附睾的脏器系数、精液品质及血清睾酮浓度均极显著降低(P<0.01),睾丸组织T-SOD活性、GSH含量也极显著降低(P<0.01),MDA含量极显著提高(P<0.01);莱菔硫烷组T-SOD活性和GSH含量显著升高(P<0.05),MDA含量与对照组相比差异不显著(P>0.05).与镉组相比,镉+莱菔硫烷组小鼠的精子活率、精子总数极显著增加(P<0.01),睾丸与附睾的脏器系数显著增加(P<0.05),小鼠睾丸组织GSH含量、T-SOD活性极显著提高(P<0.01),MDA含量极显著降低(P<0.01).以上结果指出莱菔硫烷对镉中毒雄性小鼠的生殖机能具有保护作用.     

2-Bromopropane induced germ cell apoptosis during spermatogenesis in male rat

2-Bromopropane (2-BP) causes testicular toxicity in humans and rats. However, the germ cell degeneration of testicular toxicity by 2-BP has not been understood. 2-BP at doses of 135, 405, and 1,355 mg/kg/day was daily injected subcutaneously into Sprague-Dawley rats for 28 days. At the dose of 1,355 mg/kg/day, 2-BP significantly decreased the weights of body and testes, eipididymis, seminal vesicle, and prostate, as well as daily sperm production. Atrophy of seminiferous tubules accompanied with degeneration of germ cells such as spermatogonia, spermatocytes, and elongated spermatids was observed in the testes of rats exposed to the 405 mg/kg/day and 1,355 mg/kg/day of 2-BP. TUNEL-positive germ cells were appeared in the 405 and 1,355 mg/kg/day of 2-BP-treated groups. In addition, ultrastructure alterations of apoptotic germ cells were observed by the electron microscopy study. Dead elongated spermatids were observed at 1,355 mg/kg/day after 28 days exposure. These results suggest that 2-BP impair spermatogenesis may result from apoptotic germ cell death.     

The effect of enrofloxacin on sperm quality in male mice

Current study was designed to evaluate toxic effects of enrofloxacin on male mice reproductive system. In the treatment group enrofloxacin was administered subcutaneously to male mice at a fixed dose of 150 mg/kg once daily for 15 days, whereas saline solution was given in the same regimen in the control group for the same period. Mice were sacrificed on day 15 and analyzed for sperm quality. In addition to routine examination of sperm material, spermatogenetic activity and organization of each animal were graded according to Johnsen's scoring to assess the spermatogenesis relying on seminiferous tubule cross-section scores. A significant decrease in both epididymal sperm count and sperm motility besides abnormal spermatozoa rate were observed in enrofloxacin group compared to controls (P < 0.01, for all). Johnsen's score in control mice were better than those in treatment group (P < 0.01). These results suggested that a fixed 150 mg/kg dose of enrofloxacin would lead disruption of spermatogenesis in the testes causing deterioration of motility and content of sperms as well as morphological abnormalities.     

Studies on the toxicity of an aqueous extract of the leaves of Abrus precatorius in rats

The toxic effects of an aqueous extract of Abrus precatorius were studied in 20 male white rats over a period of 18 days. The rats were divided into four groups of five rats per group. Those in Group A served as controls while the rats in Groups B, C and D were dosed per os with 400 mg/kg, 800 mg/kg and 1 600 mg/kg of the extract, respectively. Blood samples were collected for haematological and biochemical analysis and specimens of the liver, kidney and testes were taken for histopathological studies. The study showed that the extract of A. precatorius caused decreased levels of packed cell volume, haemoglobin concentration, red blood cell count, white blood cell count, mean corpuscular volume and mean corpuscular haemoglobin. The extract also resulted in increased levels of total serum protein, albumin, alanine amino transaminase, aspartate amino transferase, alkaline phosphatase and total bilirubin. Histologically, testicular degeneration characterized by decreased numbers of lining cells of the epithelium as well as reduction in sperm cells with presence of scattered Sertoli cells were noted. The study thus showed that aqueous extract of Abrus precatorius is toxic and caution should be exercised in its use for medicinal purpose.     

Effects of exposure to genistein and estradiol on reproductive development in immature male mice weaned from dams adapted to a soy-based commercial diet

Genistein, a soybean-originated isoflavone, is widely consumed by humans for putative beneficial health effects but its estrogenic activity may adversely affect the development of male reproductive system. Twenty one-day-old ICR mice weaned from dams fed with a soybean-based diet throughout gestation and lactation were exposed by gavage to genistein (2.5 mg/kg b.w./day) or 17beta-estradiol (7.5 microg/kg b.w./day) for five weeks. Corn oil was used as a negative control. The animals were fed with a casein-based AIN-76A diet throughout the experimental periods. There were no significant differences in body and organ weights of mice among experimental groups. No significant differences in sperm counts and sperm motile characteristics were found between control and genistein groups. Treatment of 17beta-estradiol caused a significant decrease in prostate weight and epididymal sperm counts compared to the control (p<0.05). The levels of phospholipid hydroxide glutathione peroxidase in the testis and prostate of mice exposed to genistein or 17beta-estradiol were significantly higher than that of the control mice (p<0.05). 17beta-estradiol treatment caused degeneration and apoptosis of germ cells in the testis, depletion and degeneration in the epididymal epithelium, and hyperplasia of mucosal fold region in the prostate of mice. Genistein treatment did not cause any lesion in the testis, epididymis, and prostate. These results suggest that dietary uptake of genistein during juvenile period may not affect male reproductive development and functions.     

成年大鼠睾丸去精索上神经对睾丸功能及肾上腺素能受体表达的影响

试验旨在研究精索上神经（superior spermatic nerve,SSN）对睾丸功能的影响,25只成年Wistar大鼠随机分为2组,试验组左右睾丸切除精索上神经,手术30 d后两组大鼠同时处死取样分析。结果显示,睾丸去精索上神经不影响睾丸指数的大小但使附睾尾精子数极显著降低（P＜0.01）,平均日增重显著增加（P＜0.05）。增殖细胞核抗原（PCNA）免疫组织化学染色结果显示,睾丸去精索上神经不影响曲细精管精原细胞和初级精母细胞的增殖,但影响曲细精管的形态和生殖细胞的规则排列。RT-PCR结果显示,睾丸去精索上神经明显上调β1AR mRNA的表达,下调β2AR mRNA的表达;另外切除精索上神经不影响睾丸3β-羟胆固醇脱氢酶（3β-HSD）mRNA表达,但显著抑制类固醇快速调节蛋白（StAR）、胆固醇侧链裂解酶（P450scc）mRNA表达（P＜0.05）。结果表明,支配睾丸的精索上神经通过调节肾上腺素能受体β1AR和β2AR的表达及StAR和P450scc影响睾丸睾酮的合成和精子的发生。     

去精索上神经(SSN)和精索下神经(ISN)对大鼠睾丸发育和精子发生的影响

本试验旨在研究睾丸神经是否参与调控睾丸的发育和精子的发生过程。大鼠出生后10 d(Postnatal day10,PD10)切断睾丸精索上神经(Superior spermatic nerve,SSN)和精索下神经(Inferior spermatic nerve,ISN),然后分别在PD25和PD50时取样分析。结果显示:睾丸去神经不影响PD25时睾丸质量和睾丸大小(P<0.05),但使PD50时的睾丸质量和睾丸尺寸极显著减小,附睾尾精子数极显著降低(P<0.01)。增殖细胞核抗原(Proliferatingcell nuclear antigen,PCNA)免疫组织化学染色显示睾丸去神经不影响PD25时生殖细胞的增殖,但却影响PD50时生殖细胞的增殖。另外RT-PCR结果显示睾丸去神经明显降低PD25时睾丸3β-羟胆固醇脱氢酶1(3β-hydroxysterol dehydrogenase 1,3β-HSD1)mRNA的表达(P<0.05),并明显抑制PD50时3β-HSD1和雄激素结合蛋白(Androgen binding protein,ABP)mRNA表达(P<0.01)以及黄体生成素受体(Lute...     

In vitro study on the increase of trypsin resistance in the rat testicular sperm head.

The alteration of trypsin resistance in rat sperm head was investigated after the sperm were incubated in the culture media (199-Earele, 1% BSA) containing the inhibitors of protein synthesis. The head of non-incubated testicular sperm was easily digested by trypsin (1 mg/ml) while the head of the incubated sperm showed resistance to trypsin digestion after 3 hr-incubation. Trypsin resistance in epididymal sperm head did not change after the sperm was incubated. Neither cycloheximide (100 micrograms/ml) nor chloramphenicol (100 micrograms/ml) affected the trypsin resistance in the testicular sperm head.     

Abnormalities of the Testes and Epididymis in Bucks and Rams Slaughtered at Debre Zeit Abattoir,Ethiopia

A study was conducted at Debre Zeit export abattoir on 404 bucks belonging to four breeds and 167 rams of two breeds. The animals were selected from the slaughter flock using stratified sampling based on breed. Ante-mortem and post-mortem examinations were carried out after each animal was carefully identified. Various genital abnormalities were observed, among which testicular atrophy and epididymitis were the predominant genital problems in both bucks and rams. The prevalence of cryptorchidism was higher (p<0.05) in bucks than in rams, while epididymitis (p<0.05), sperm granuloma (p<0.01) and epididymal cysts (p<0.05) were more frequent in rams. In bucks, none of these abnormalities was significantly associated with age (p>0.05). However, testicular atrophy (p<0.01), epididymitis (p<0.01) and haemorrhagic lesions (p<0.05) were associated with breed, the prevalence being higher in Woito-Guji and Boran bucks than in the Arsi-Bale and Afar breeds. In rams, age affected (p<0.05) the incidence of testicular atrophy, epididymitis and sperm granulomas. Epididymitis, sperm granuloma and epididymal cysts were more frequent (p<0.01) in Adal rams than in Black Head Somalis.     

Decreased sperm number and motile activity on the F1 offspring maternally exposed to butyl p-hydroxybenzoic acid (butyl paraben)

Butyl p-hydroxybenzoic acid (butyl paraben, BP) is widely used as a preservative in food and cosmetic products. Routledge et al showed that BP is weakly estrogenic in both in vitro and in vivo (rat uterotrophic) analyses. We investigated whether maternal exposures to BP during gestation and lactation periods affected the development of the reproductive organs of the F1 offspring. Pregnant Sprague-Dawley rats were injected subcutaneously with 100 or 200 mg/kg of BP from gestation day (GD) 6 to postnatal day (PND) 20. In the group exposed to 200 mg/kg of BP, the proportion of pups born alive and the proportion of pups surviving to weaning were decreased. The body weights of female offspring were significantly decreased at PND 49. The weights of testes, seminal vesicles and prostate glands were significantly decreased in rats exposed to 100 mg/kg of BP on PND 49. In contrast, the weights of female reproductive organs were not affected by BP. The sperm count and the sperm motile activity in the epididymis were significantly decreased at doses of 100 and 200 mg/kg of BP. In accordance with the sperm count in the epididymis, the number of round spermatids and elongated spermatids in the seminiferous tubule (stage VII) were significantly decreased by BP. Testicular expression of estrogen receptor (ER)-alpha and ER-beta mRNA was significantly increased in 200 mg/kg of BP treated group at PND 90. Taken together, these results indicated that maternal exposure of BP might have adverse effects on the F1 male offspring.     

Relationships among scrotal and testicular characteristics, sperm production, and seminal quality in 129 beef bulls.

Standard breeding soundness examinations plus measurement of scrotal surface temperature (SST), internal/scrotal testicular temperatures, testicular ultrasonographic echotexture, daily sperm production, and epididymal sperm reserves were conducted on 129, 16-month-old crossbred beef bulls. There were significant positive linear correlations between SST and internal scrotal/testicular temperatures, a positive linear regression (P < 0.06) of bottom SST with the incidence of secondary sperm defects, but a negative linear regression (P < 0.01) with the incidence of primary sperm defects. Testicular echotexture had a positive linear regression with daily sperm production (P < 0.002) and testicular tone had a negative linear regression (P < 0.008) with epididymal sperm reserves. Scrotal circumference had a positive linear regression (P < 0.04) with the percentage of progressively motile sperm, a negative linear regression (P < 0.1) with the incidence of primary sperm defects, and a positive linear regression (P < 0.0001) with epididymal sperm reserves. In addition to seminal quality and scrotal circumference, testicular ultrasonographic echotexture has considerable promise for augmenting breeding soundness examinations of bulls.     

Comparison of cupric and sulfate ion effects on chronic selenosis in rats

The ameliorating effects of Cu++ and SO4--ions on concurrent selenite toxicity were compared in two factorial experiments using 60 weanling rats each. In the first experiment, 0, 500 and 1,000 mg Cu (as CuCl2)/kg diet were fed in conjunction with 0, 5, 10 and 20 mg Se (as Na2SeO3)/kg diet. In the second experiment, the treatments were 0, 500 and 1,000 mg SO4 (as Na2SO4)/kg fed in conjunction with 0, 5, 10 and 20 mg Se/kg diet. A paired-feeding experiment using 10, 15 and 20 mg Se/kg diet was also conducted with 28 rats to compare the influence of inanition in control and selenite-fed rats. Cupric++ ion, but not SO4--ion, prevented mortality among selenite-intoxicated rats. There were significant Cu X Se interaction effects on feed intake, daily gain, packed cell volume (PCV), serum Cu and Fe, sperm counts, and weights of liver, kidney and testis. There were main effects of Cu and Se on serum Se and liver Cu. In Exp. 2 there were significant SO4 X Se interaction effects on feed intake, daily gain, serum Cu and testis weight. There were main effects of Se on PCV, sperm count, serum testosterone, liver Se, liver Cu and the absolute weights of liver and kidney. The only main effect of SO4 was that of increased liver Cu concentrations. Among the pair-fed rats, the selenite-fed rats, with one exception, died before their paired rats.(ABSTRACT TRUNCATED AT 250 WORDS)     

氧化乐果对雄性小鼠睾丸琥珀酸脱氢酶和精液质量的影响

试验旨在研究有机磷农药氧化乐果对雄性小鼠睾丸琥珀酸脱氢酶(SDH)和精液质量的影响作用。将40只健康昆明雄性小鼠随机分为4组,即低、中、高3个染毒组和对照组,其中染毒组分别灌胃1.0、2.0、4.0 mg/kg氧化乐果,对照组灌胃生理盐水,采用等容量灌胃法(0.2 mL/10 g体重),连续灌胃14 d。随着氧化乐果染毒剂量的逐渐增加,小鼠睾丸琥珀酸脱氢酶(SDH)活力、精子密度、存活率均明显降低,与对照组相比差异显著(P＜0.05);小鼠体重、睾丸重、附睾及其脏器系数与对照组相比差异均不显著(P＞0.05)。氧化乐果对小鼠精子密度和精子存活率有一定的损伤作用,对睾丸琥珀酸脱氢酶有明显的抑制作用。     

Effects of the β2 -agonist clenbuterol on testicular steroidogenic acute regulatory protein mRNA expression in adult rats

Ma, J.‐K., Zhu, W.‐J. Effects of the β₂‐agonist clenbuterol on testicular steroidogenic acute regulatory protein mRNA expression in adult rats. J. vet. Pharmacol. Therap. 33 , 558–563. This study was carried out to investigate the effects of clenbuterol (CLB) on the testicular (steroidogenic acute regulatory, StAR) protein mRNA expression in rats. Thirty adult male rats were administered CLB by gavage daily at the doses of 0.4, 2.0 and 18.5 mg/kg bw for 14 days in the subacute experiment, whereas 20 rats received a single treatment with CLB at the doses of 20 and 40 mg/kg bw in the acute experiment and 20 rats were treated with 0.9% NaCl solution as vehicle groups. Testicular tissues were collected and snap‐frozen in liquid nitrogen and stored at ?70 °C until use. The levels of StAR mRNA were detected by RT–PCR. The levels of StAR mRNA were markedly increased (P < 0.05) at both dosages of 20 and 40 mg/kg bw but the effects were not dose‐dependent and the mRNA levels of StAR were returned to near normal level after 7 days of CLB withdrawal, compared with the control animals. In the subacute experiment, CLB induced a dose‐dependent but no statistical significant reduction (P > 0.05) in the expression levels of StAR mRNA, and the mRNA levels were recovered to near normal level in the groups treated with CLB at dosages of 0.4 and 2.0 mg/kg bw/day following a 7‐day withdrawal period, compared with the control animals. The mRNA levels of StAR showed a significant decrease in the groups treated with CLB at the dosage of 18.5 mg/kg bw/day (P < 0.05) after a 1‐ or 7‐day withdrawal period with respect to the control animals. These results demonstrated transient stimulative effects of CLB on testicular StAR mRNA levels and inhibitory effects after treatment with CLB for 14 consecutive days.