Ribavirin-induced sperm shape abnormalities in Wistar rat.

Ribavirin (1-beta-D-ribofuranosyl-1,2,4, triazole-3 carboxamide) is a broad-spectrum antiviral drug. This study was aimed to investigate the mutagenicity of ribavirin on germ cells by employing sperm morphology assay. Male Wistar rats were treated with water, cyclophosphamide (CP) 40 mg/kg, and ribavirin 20, 100 and 200 mg/kg (i.p.) for 5 consecutive days at intervals of 24h. Following the last exposure, at 14, 28, 35, 42 and 70 days, the epididymal sperm smears were obtained and stained according to the standard procedure. One thousand sperms per animal were classified into normal and different abnormal types. Both CP and ribavirin-induced anomalies of head and tail of sperm except at 70 days. In CP groups, maximum incidence was observed at 28, 35 and 42 days. Ribavirin 20 mg/kg induced maximum incidence at 14 and 42 days, 100 mg/kg at 28 and 42 days and 200 mg/kg at 28-42 days. These results show that ribavirin is mutagenic to rat germ cells in a transient fashion.     

Ribavirin-induced sperm shape abnormalities in Wistar rat

Ribavirin (1-β-d-ribofuranosyl-1,2,4, triazole-3 carboxamide) is a broad-spectrum antiviral drug. This study was aimed to investigate the mutagenicity of ribavirin on germ cells by employing sperm morphology assay. Male Wistar rats were treated with water, cyclophosphamide (CP) 40 mg/kg, and ribavirin 20, 100 and 200 mg/kg (i.p.) for 5 consecutive days at intervals of 24 h. Following the last exposure, at 14, 28, 35, 42 and 70 days, the epididymal sperm smears were obtained and stained according to the standard procedure. One thousand sperms per animal were classified into normal and different abnormal types. Both CP and ribavirin-induced anomalies of head and tail of sperm except at 70 days. In CP groups, maximum incidence was observed at 28, 35 and 42 days. Ribavirin 20 mg/kg induced maximum incidence at 14 and 42 days, 100 mg/kg at 28 and 42 days and 200 mg/kg at 28-42 days. These results show that ribavirin is mutagenic to rat germ cells in a transient fashion.     

Ginkgo biloba extract enhances male copulatory behavior and reduces serum prolactin levels in rats

The aim of this study was to investigate the effects of Ginkgo biloba extract (EGb 761) on male copulatory behavior in rats. EGb 761 (1 mg/ml) induced significant production of testosterone (T) in rat Leydig cells in vitro. Its effects on sexual behavior were then tested in Long-Evans male rats after 7, 14, 21, or 28 days of oral gavage of vehicle (distilled water) or EGb 761 at doses of 10, 50, or 100 mg/kg. Administration of 50 mg/kg of EGb 761 for 28 days and of 100 mg/kg for 14 or 21 days significantly increased intromission frequency compared to controls on the same day. An increase in ejaculation frequency was seen after treatment with 50 mg/kg of EGb 761 for 14, 21, or 28 days when compared to either the control group on the same day or the same group on day 0. A reduction in ejaculation latency was only seen after administration of 50 mg/kg of EGb 761 for 14 days compared to the vehicle-treated group. After treatment for 28 days, no significant difference was seen in mount latency, intromission latency, serum T levels, reproductive organ weight, sperm number, or levels of the metabolite of dopamine, 3,4-dihydroxyphenylacetic acid in the brain with any dose of EGb 761, but significantly reduced serum prolactin levels and increased dopamine levels in the medial preoptic area and arcuate nucleus were seen at the dose of 50 mg/kg. These findings show that EGb 761 (especially at the dose of 50 mg/kg) enhances the copulatory behavior of male rats and suggest that the dopaminergic system, which regulates prolactin secretion, may be involved in the facilitatory effect of EGb 761.     

Effects of methyl parathion (o,o-dimethyl o-4-nitrophenyl phosphorothioate) on rat sperm morphology and sperm count, but not fertility, are associated with decreased ascorbic acid level in the testis

Methyl parathion (MP; o,o-dimethyl o-4-nitrophenyl phosphorothioate) is an organophosphorous pesticide used world wide to spray agricultural crops. The present study was aimed to investigate the genotoxic and cytotoxic effects on male germ cells and their possible relation with testicular ascorbic acid levels. Adult male Wistar rats (n=5/group) received MP at 0, 0.5, or 1 mg/kg (experiments 1 and 2) for 12 days and 0, 0.75 or 1.5 mg/kg (experiment 3) for 25 days (i.p.) everyday at intervals of 24 h. The epididymal sperm count, sperm abnormalities and testicular ascorbic acid levels (by 2,4-dinitrophenyl hydrazine method) were estimated on days 130, 77 and 17 following the last exposure in experiments 1, 2, and 3, respectively. Virgin untreated female rats were mated with treated males from experiments 2 and 3 for a week effective from day 35 to 41 after the first treatment, and fertility indices were measured after the birth of pups. Sperm count was decreased in experiments 2 and 3 (P<0.01), and in all three experiments, the abnormal sperms increased (P<0.001). Concomitantly, the ascorbic acid levels decreased in the testis (P<0.05-0.001; one-way ANOVA and Bonferroni's post hoc test). The body weights of offspring of treated males did not show significant changes from those of the controls, although there were some decreases observed. MP reduced the lactation index in experiment 2 (P<0.001; Chi-square test). The number of pups/parent along with fertility indices showed some numerical decrease but without any statistical significance. The present findings suggest that MP is a weak genotoxic and cytotoxic agent in the rat exposed to human exposure dose-levels, and that these effects, except the fertility are well correlated with decreased ascorbic acid level in the testis. Furthermore, MP-induced changes in the germ cells do not have any significant effects on F1 generation.     

The mouse teratogen dinocap has lower A/D ratios and is not teratogenic in the rat and hamster

The fungicide dinocap is currently used in the control of powdery mildew. We have reported that dinocap is teratogenic in the CD-1 mouse, causing cleft palate, otolith defects, and fetal weight deficits well below maternotoxic dose levels. In this study the maternal and fetal toxicity of dinocap was determined in the Sprague-Dawley rat and Syrian golden hamster, and adult-to-developmental (A/D) toxicity ratios were calculated and compared with the previously established A/D ratio of dinocap in the mouse. Dinocap in corn oil was administered by gavage to pregnant rats on gestation days 7-20 (0, 100, 150, 200 mg/kg/day) and to hamsters on gestation days 7-14 (0, 12.5, 25, 50, 75, 100, 200 mg/kg/day). Dams were killed on day 21 (rat) or day 15 (hamster), and litters were removed, counted, and weighed; half of each litter was necropsied for soft tissue defects, and the remaining half was processed for skeletal examination. In the rat, maternal extrauterine weight gain was significantly affected at 150 and 200 mg/kg/day, relative liver weight was elevated at 100 mg/kg/day and above, and fetal weight was lower at 150 and 200 mg/kg/day. In the hamster, maternal extrauterine weight was lower at 12.5 mg/kg/day and above; fetal weight was reduced, and the incidence of dilated renal pelvis was higher, at 25 mg/kg/day and above. Thus the A/D ratios for dinocap in the rat and hamster are similar, approximately 1.(ABSTRACT TRUNCATED AT 250 WORDS)     

Teratologic evaluation of synthetic delta-9-tetrahydrocannabinol in rats.

Delta-9-Tetrahydrocannabinol (THC) was dissolved in propylene glycol and 25, 50, or 100 mg/kg administereed dialy sc to pregnant Charles River Sprague-Dawley rats on days 6-15 of gestation (presence of sperm considered day 1). Maternal weight gain was depressed, but a significant decrease in fetal weight occurred only in the 50 mg/kg group. No malformations were noted, only some abnormalities consisting of several instances of rudimentary 14th rib and soft or spongy spinal cords.     

Effects of Dietary Zinc Oxide Nanoparticles on Growth Performance and Antioxidative Status in Broilers

Broilers in four groups were fed a basal diet supplemented with 60 mg/kg zinc oxide (60-ZnO; control), or 20, 60, or 100 mg/kg ZnO nanoparticles (20-, 60-, and 100-nano-ZnO, respectively). Compared with the controls, after 14 days, birds in the 20- and 60-nano-ZnO groups had significantly greater weight gains and better feed conversion ratios. However, the body weight of birds in the 100-nano-ZnO group was dramatically reduced after 28 days. Relative to the control group, the total antioxidant capability (T-AOC) in serum and liver tissue was significantly higher in the 20-nano-ZnO group at all time points and also significantly higher in the 60- and 100-nano-ZnO groups in serum on days 28 and 35 and in liver tissues on days 21 and 28. Compared with the controls, the activity of copper-zinc superoxide dismutase (Cu-Zn-SOD) was significantly greater in the 60- and 100-nano-ZnO groups in serum on days 28 and 35 and in liver tissues after 21 days. Catalase activity in serum samples was significantly higher in the 20- and 60-nano-ZnO groups relative to the control and 100-nano-ZnO birds, but catalase activity in liver tissue was not affected by different nano-ZnO levels. Malondialdehyde content in serum and liver tissues was significantly reduced in the 20-, 60-, and 100-nano-ZnO groups compared with that in the control group at all time points except day 42. Taken together, our data indicate that appropriate concentration of dietary ZnO nanoparticles improves growth performance and antioxidative capabilities in broilers, and 20 mg/kg nano-ZnO is the optimal concentration.     

Use of a Taqman PCR to determine the response of Mycoplasma haemofelis infection to antibiotic treatment

A quantitative Taqman polymerase chain reaction (PCR) assay was used to evaluate the response of Mycoplasma haemofelis experimentally infected cats to three antibiotic treatment regimes. Sixteen cats were intravenously inoculated with M. haemofelis from a chronically infected donor. The cats were randomly assigned to one of four treatment groups each containing four cats: oral doxycycline at 10 mg/kg/day for 14 days, oral enrofloxacin at 5 mg/kg/day for 14 days, oral enrofloxacin at 10 mg/kg/day for 14 days, and an untreated control group. DNA, extracted from blood samples collected on days 0, 7, 14, 21, 25, 28, 32, 35, 42 and 54 post-inoculation (PI), was subjected to quantitative Taqman PCR. The M. haemofelis copy number was significantly lower in the doxycycline group (P=0.008), the 5 mg/kg/day enrofloxacin group (P=0.006) and the 10 mg/kg/day enrofloxacin group (P=0.005) compared to the untreated control group. No significant differences were found between any of the three antibiotic treated treatment groups. All three antibiotic treatment regimes evaluated in this study were effective at reducing M. haemofelis copy number.     

Novel (S)-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acids: peroxisome proliferator-activated receptor γ selective agonists with protein-tyrosine phosphatase 1B inhibition

A novel series of 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid derivatives were synthesized and (S)-2-[(2E,4E)-hexadienoyl]-7-(2-{5-methyl-2-[(1E)-5-methylhexen-1-yl]oxazol-4-yl}ethoxy)-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid (14i) was identified as a potent human peroxisome proliferator-activated receptor γ (PPARγ) selective agonist (EC(50)=0.03 μM) and human protein-tyrosine phosphatase 1B (PTP-1B) inhibitor (IC(50)=1.18 μM). C(max) after oral administration of 14i at 10mg/kg was 2.2 μg/ml (4.5 μM) in male SD rats. Repeated administration of 14i and rosiglitazone for 14 days dose-dependently decreased plasma glucose levels, ED(50)=4.3 and 23 mg/kg/day, respectively, in male KK-A(y) mice. In female SD rats, repeated administration of 14i at 12.5-100mg/kg/day for 28 days had no effect on the hematocrit value (Ht) and red blood cell count (RBC), while rosiglitazone significantly decreased them from 25mg/kg/day. In conclusion, 14i showed about a fivefold stronger hypoglycemic effect and fourfold or more weaker hemodilution effect than rosiglitazone, indicating that 14i is 20-fold or more safer than rosiglitazone. Compound 14i is a promising candidate for an efficacious and safe anti-diabetic drug targeting PPARγ and PTP-1B.     

The effect of carbamazepine on sperm counts in Wistar rats--reflecting upon its mitogenic potential

The present study was aimed to investigate the effects of carbamazepine, an antiepileptic drug, on sperm count in rats. Male Wistar rats were treated with carbamazepine at doses of 9, 18, and 36 mg/kg for five consecutive days. Following the last exposure, on days 14 and 35, spermatozoa were collected from epididymis and counted. On day 14, carbamazepine treatment decreased the sperm number in a dose dependent pattern. On day 35, 9 mg/kg and 36 mg/kg of carbamazepine increased the sperm number in comparison with untreated rats. The results of the study suggest that carbamazepine is a germ cell mitogen.     

Modulation of rat Leydig cell steroidogenic function by di(2-ethylhexyl)phthalate

Exposure of rodents to phthalates is associated with developmental and reproductive anomalies, and there is concern that these compounds may be causing adverse effects on human reproductive health. Testosterone (T), secreted almost exclusively by Leydig cells in the testis, is the primary steroid hormone that maintains male fertility. Leydig cell T biosynthesis is regulated by the pituitary gonadotropin LH. Herein, experiments were conducted to investigate the ability of di(2-ethylhexyl)phthalate (DEHP) to affect Leydig cell androgen biosynthesis. Pregnant dams were gavaged with 100 mg(-1) kg(-1) day(-1) DEHP from Gestation Days 12 to 21. Serum T and LH levels were significantly reduced in male offspring, compared to control, at 21 and 35 days of age. However, these inhibitory effects were no longer apparent at 90 days. In a second set of experiments, prepubertal rats, from 21 or 35 days of age, were gavaged with 0, 1, 10, 100, or 200 mg(-1) kg(-1) day(-1) DEHP for 14 days. This exposure paradigm affected Leydig cell steroidogenesis. For example, exposure of rats to 200 mg(-1) kg(-1) day(-1) DEHP caused a 77% decrease in the activity of the steroidogenic enzyme 17beta-hydroxysteroid dehydrogenase, and reduced Leydig cell T production to 50% of control. Paradoxically, extending the period of DEHP exposure to 28 days (Postnatal Days 21-48) resulted in significant increases in Leydig cell T production capacity and in serum LH levels. The no-observed-effect-level and lowest-observed-effect-level were determined to be 1 mg(-1) kg(-1) day(-1) and 10 mg(-1) kg(-1) day(-1), respectively. In contrast to observations in prepubertal rats, exposure of young adult rats by gavage to 0, 1, 10, 100, or 200 mg(-1) kg(-1) day(-1) DEHP for 28 days (Postnatal Days 62-89) induced no detectable changes in androgen biosynthesis. In conclusion, data from this study show that DEHP effects on Leydig cell steroidogenesis are influenced by the stage of development at exposure and may occur through modulation of T-biosynthetic enzyme activity and serum LH levels.     

Effects of thalidomide on reproductive function and early embryonic development in male and female New Zealand white rabbits

BACKGROUND : The present work was performed to determine the effect of thalidomide exposure on reproductive function and early embryonic development. METHODS : Twenty‐five female New Zealand White rabbits were orally gavaged with 0, 10, 50, or 100 mg/kg/day thalidomide 14 days prior to mating through to gestation day 7 for a total of 22 days. Treated females were Caesarean‐sectioned approximately 29 days after the date of attempted mating. Following mating with treated females, male rabbits (25/dose) were gavaged with 0, 30, 150, or 500 mg/kg/day beginning 14 days prior to mating with a group of untreated females (25/dose). Doses were administered through mating until the day before sacrifice for a minimum of 56 days. Untreated females were Caesarean‐sectioned 29 days after the last attempted mating. Comprehensive necropsy and histopathology of the reproductive system were performed. RESULTS : Treated females had reduction in body weight gain during gestation. Mating and pregnancy parameters were unaffected by thalidomide. At 100 m/kg, litter averages for corpora lutea, implantations, litter sizes, does with viable fetuses and live fetuses decreased and the number of early resorptions, does with any resorptions, does with all conceptuses resorbed, and the percent resorbed conceptuses per litter increased. The number of early resorptions, the average number of early resorptions per litter, and the percent resorbed conceptuses per litter increased at 10 and 50 mg/kg. There were no thalidomide‐related external fetal malformations. Mating and fertility in male rabbits were unaffected by thalidomide. There was an increased incidence of flaccid testes at 150 and 500 mg/kg and of bilateral small testes in all treated groups. At 500 mg/kg, there was degeneration of the germinal epithelium of the testicles with an increase in multinucleated giant cells in seminiferous tubule and a loss of round and elongating spermatids. CONCLUSIONS : Thalidomide had no adverse effects on mating and fertility in male and female rabbits dosed up to 500 and 100 mg/kg/day, respectively, for 14 days prior to mating. After 56 day of dosing, histopathologic changes with no associated sperm abnormalities were observed in the testicles. Embryonic development NOAEL for treated females mated to untreated males was <10 mg/kg. Corresponding fertility NOAEL for treated males mated to untreated females was 500 mg/kg. Birth Defects Res B 71:1–16, 2004. © 2004 Wiley‐Liss, Inc.     

The effect of gabapentin and phenytoin on sperm-morphology in Wistar rats

The objective of the present study was to investigate the effects of the antiepileptic drugs, gabapentin and phenytoin, on sperm morphology in Wistar rats. Groups (n=5) of rats were treated with cyclophosphamide (20 mg/day), gabapentin (16, 25, 32 mg/day) and phenytoin (3.5, 5.5, 7 mg/day) for five consecutive days. 14 and 35 days after the last exposure, sperm morphology was evaluated by standard procedure. Gabapentin and phenytoin did not induce significant changes in sperm morphology. The results suggest that phenytoin and gabapentin are not germ cell mutagens in males, and do not appear to adversely affect male fertility.     

Benzofuranyl ureas with potent cardiovascular teratogenicity in rats

Studies of embryo-fetal development in rats were conducted with two 5-lipoxygenase inhibitors. SB-202235 (1,000 mg/kg/day) or SB-210661 (50, 100, or 500 mg/kg/day) was administered orally by gavage to female rats on days 6-17 postcoitus (pc) or days 7-16 pc. SB-202235 (1,000 mg/kg/day) and SB-210661 (100 mg/kg/day) reduced maternal body weight gain for the treatment period by 16% and 21%, respectively, relative to controls. SB-202235 (1,000 mg/kg/day) or SB-210661 (50 or 100 mg/kg/day), did not affect numbers of resorptions, dead or live fetuses/litter, but 500 mg/kg/day of SB-210661 caused 100% embryo lethality. SB-202235 (1,000 mg/kg/day) and SB-210661 (50 and 100 mg/kg/day) reduced fetal body weight by 15-30% and produced extensive cardiovascular malformations, as well as diaphragmatic hernias. SB-210661 also caused thymic abnormalities and cryptorchidism. Cardiovascular defects included abnormalities in aorticopulmonary septation, the aortic arch, pulmonary trunk, and ventricular septal defects are discussed relative to comparable human syndromes of cardiovascular malformation.     

Effects of pre-synchronization using combinations PGF(2alpha) and (or) GnRH on pregnancy rates of Ovsynch- and Cosynch-treated lactating Holstein cows

In Experiment 1, the effects of two pre-synchronization treatments on synchronized AI pregnancy rates of lactating dairy cattle were compared. Lactating Holstein cows (n=159) received 100 microg of GnRH (im) on day -7 and 25mg of PGF(2alpha) (im) on day 0 and were observed once daily for signs of estrus from day -3 to day 3. Cows detected in standing estrus and those that had lost significant amounts of tail-chalk in the previous 24h were immediately inseminated in a once-daily observation/AI program. Cows not detected in estrus by 72 h after PGF(2alpha) received fixed-time AI (TAI) and a concurrent 100 microg injection of GnRH (im). Cows were randomly assigned by parity and calving date to receive one of the following pre-synchronization treatments: (1) 25mg of PGF(2alpha) (im) on day -35 and day -21 (PGF-PGF) or (2) 100 microg of GnRH (im) on day -14 (GnRH). Fewer (P<0.05) GnRH- (49%, 41/84) than PGF-PGF-pretreated cows (65%, 49/75) were detected in estrus, however, overall pregnancy rates were not affected by pre-synchronization treatment (30 versus 32%, respectively). In Experiment 2, lactating Holstein cows received 100 microg of GnRH (im) on day -7, 25mg of PGF(2alpha) (im) on day 0 and TAI at 60-64 h after PGF(2alpha). Cows were randomized by parity and postpartum interval into pre- and post-synchronization treatments in a 2 x 2 factorial design. Pre-synchronization treatments included: (1) 25mg of PGF(2alpha) (im) on day -35 and on day -21 (PGF-PGF; n=168) or (2) 25mg of PGF(2alpha) (im) on day -21 and 100 microg of GnRH (im) on day -14 (PGF-GnRH; n=180). Within each pre-synchronization treatment, cows were further allocated by parity and postpartum interval to receive as a post-synchronization treatment 100 microg of GnRH (im) at either 48 h (Ovsynch; n=175) or 60-64 h (Cosynch; n=173) after PGF(2alpha). Pregnancy rates at TAI were not affected by pre- (PGF-PGF=26%, 44/168 versus PGF-GnRH=24%, 44/180) or post-synchronization treatments (Ovsynch=29%, 50/175 versus Cosynch=22%, 38/173). However, the numeric shift towards reduced pregnancy rates in Cosynch-treated cows suggests the 12h interval between GnRH and AI may be important to optimize conception rates in GnRH-PGF(2alpha)-based TAI protocols in dairy cattle. In conclusion, each of the pre-synchronization protocols evaluated in present study performed with comparable efficacy. Although the Cosynch protocol facilitates more efficient labor utilization, numeric trends toward reduced conception warrants further investigation.     

Induction of sperm abnormalities in mice by ifosfamide and trofosfamide

The antitumor drugs ifosfamide (IF) and trofosfamide (TF) were evaluated for their capability to induce sperm abnormalities in (C3H X C57BL/6)F1 mice. A statistically significant increase in teratospermia was observed at the 35th day after 5 daily consecutive intraperitoneal injections of the drugs at doses of 25, 50, 100 mg/kg b.w. of TF and 100 mg/kg b.w. of IF. Thus, IF and TF are able to interfere with the differentiation process of spermatogenic cells.     

Ethyl methanesulphonate induced changes in the differentiation, structure and functions of spermatozoa of the house rat,Rattus rattus L.

Intraperitoneal administration of 500 mg/kg and 625 mg/kg doses of the germ cell mutagen, ethyl methanesulphonate (EMS) in 5 consecutive days to the house rat,Rattus rattus caused a dose-dependent reduction in its body weight, cauda epididymides weight, concentration, motility and percentage of live spermatozoa with simultaneous increase in the percentage of their abnormal forms. Compared to 0·65% spermatozoa with abnormal heads in the cauda epididymidis of untreated control rats, 24·86% and 65·72% such spermatozoa were observed in rats on day 14 post treatment with 500 mg/kg and 625 mg/kg doses of EMS respectively. On day 28 post treatment corresponding values for abnormal spermatozoa were 16·21% and 14·32%. Similarly, spermatozoa with abnormal flagella increased from 0.78% in control rats to 9·25% and 5·75% on day 14 post treatment of 500 and 625 mg/kg doses of EMS respectively and declined to 2·91% and 2·40% on day 28 post treatment. Abnormality in the sperm head was mainly due to acrosomelessness and in the flagellum due to bending at proximal region. However, the main effect of EMS was the development of spermatozoa without or deformed acrosomes which may impair the fertility of rats. Analysis of various stages of differentiation of spermatozoa inthe testis revealed that population of preleptotene and pachytene spermatocytes and of round spermatids showed a gradual decline which became significantly less than controls on day 28 of EMS treatment. Occurrence of abnormal heads of testicular spermatids indicated that the sperm head abnormalities originated in the testis during late spermiogenesis.     

Effects of rumen-protected choline supplementation on milk production and choline supply of periparturient dairy cows

The objective of the present study was to determine the effects of rumen-protected choline (RPC) supplementation on body condition, milk production and milk choline content during the periparturient period. Thirty-two Holstein cows were allocated into two groups (RPC group - with RPC supplementation, and control group - without RPC supplementation) 28 days before the expected calving. Cows were fed the experimental diet from 21 days before expected calving until 60 days of lactation. The daily diet of the RPC group contained 100 g of RPC from 21 days before calving until calving and 200 g RPC after calving for 60 days of lactation, which provided 25 g and 50 g per day choline, respectively. Body condition was scored on days -21, 7, 35 and 60 relative to calving. Milk production was measured at every milking; milk fat, protein and choline content were determined on days 7, 35 and 60 of lactation. Body condition was not affected by RPC supplementation. Milk yield was 4.4 kg higher for the group of cows receiving supplementary choline during the 60 days experimental period and 4% fat-corrected milk production was also increased by 2.5 kg/day. Milk fat content was not altered by treatment, but fat yield was increased by 0.10 kg/day as a consequence of higher milk yield in the RPC-treated group. Milk protein content tended to increase by RPC supplementation and a 0.18 kg/day significant improvement of protein yield was detected. Milk choline content increased in both groups after calving as the lactating period advanced. However, milk choline content and choline yield were significantly higher in the RPC group than in the control group. The improved milk choline and choline yield provide evidence that some of the applied RPC escaped ruminal degradation, was absorbed from the small intestine and improved the choline supply of the cows and contributed to the changes of production variables.     

不同剂量博莱霉素诱导小鼠肺纤维化的差异及动态变化

目的探讨博来霉素诱导小鼠肺纤维化最佳剂量和方法。方法 126只8周龄雄性ICR小鼠,随机分成一次性大剂量模型和多次小剂量模型。一次性大剂量模型分为200 mg/(kg.bw)BLM组、150 mg/(kg.bw)BLM组、100 mg/(kg.bw)BLM组及阴性对照组(DN组),每组18只,分别经尾静脉一次性注射BLM 200、150、100mg/(kg.bw)及生理盐水10 mL/(kg.bw),各组分别于第7、14、21天各处死6只。多次小剂量模型分为每日10 mg/(kg.bw)BLM组及阴性对照组(N组),分别经尾静脉注射BLM 10 mg/(kg.bw)及生理盐水10 mL/(kg.bw),每天1次,连续注射14 d,两组分别于第14、21、28天各处死6只。留取肺组织,观察肺组织病理改变,检测Ⅲ型胶原的含量,观察小鼠体重及生存率。结果①在一次性大剂量模型中,BLM各剂量组肺泡炎症评分及肺纤维化评分与正常组相比,除100 mg/(kg.bw)BLM组和150 mg/(kg.bw)BLM组在第7天的模型差异无显著性外(P>0.05),其余各组差异均有显著性(P<0.05);各个剂量组Ⅲ型胶原的表达面积与正常组相比,除100 mg/(kg.bw)BLM组在第7天的模型差异无显著性外(P>0.05),其余各组均较正常组高(P<0.05),各个剂量组分别在第21天达到高峰,以200 mg/(kg.bw)BLM组第21天组Ⅲ型胶原的表达面积最高;该模型小鼠各剂量组死亡率为0。②在多次小剂量模型中,各组的肺泡炎症与肺纤维化程度与正常组相比差异均有显著性(P<0.05);各组Ⅲ型胶原的表达也均高于正常组(P<0.05),且随着时间的延长呈进行性增加,在第28天达到高峰;该模型小鼠共死亡11只,死亡率为30.56%。结论在本实验中,以尾静脉一次性注射BLM 200 mg/(kg.bw)后第21天诱导建立的ICR小鼠肺纤维化模型成模最好,其小鼠死亡率低,操作简单,有效安全方便的特点使之有希望成为一种复制肺纤维化的理想模型。     

Effects of a unique conjugate of alpha-lipoic acid and gamma-linolenic acid on insulin action in obese Zucker rats

The purpose of this study was to assess the individual and interactive effects of the antioxidant alpha-lipoic acid (LPA) and the n-6 essential fatty acid gamma-linolenic acid (GLA) on insulin action in insulin-resistant obese Zucker rats. LPA, GLA, and a unique conjugate consisting of equimolar parts of LPA and GLA (LPA-GLA) were administered for 14 days at 10, 30, or 50 mg. kg body wt(-1). day(-1). Whereas LPA was without effect at 10 mg/kg, at 30 and 50 mg/kg it elicited 23% reductions (P < 0.05) in the glucose-insulin index (the product of glucose and insulin areas under the curve during an oral glucose tolerance test and an index of peripheral insulin action) that were associated with significant increases in insulin-mediated (2 mU/ml) glucose transport activity in isolated epitrochlearis (63-65%) and soleus (33-41%) muscles. GLA at 10 and 30 mg/kg caused 21-25% reductions in the glucose-insulin index and 23-35% improvements in insulin-mediated glucose transport in epitrochlearis muscle. The beneficial effects of GLA disappeared at 50 mg/kg. At 10 and 30 mg/kg, the LPA-GLA conjugate elicited 29 and 38% reductions in the glucose-insulin index. These LPA-GLA-induced improvements in whole body insulin action were accompanied by 28-63 and 38-57% increases in insulin-mediated glucose transport in epitrochlearis and soleus muscles and resulted from the additive effects of LPA and GLA. At 50 mg/kg, the metabolic improvements due to LPA-GLA were substantially reduced. In summary, these results indicate that the conjugate of the antioxidant LPA and the n-6 essential fatty acid GLA elicits significant dose-dependent improvements in whole body and skeletal muscle insulin action on glucose disposal in insulin-resistant obese Zucker rats. Moreover, these actions of LPA-GLA are due to the additive effects of its individual components.