Effects of in utero ethanol exposure on cortical 5-HT2 binding sites

Previous studies by this laboratory found that in utero ethanol exposure results in a decrease of several presynaptic components of serotonin (5-HT) containing neurons in the cerebral cortex and cortical regions. The present study examined whether in utero ethanol exposure similarly affects the development of the cortical targets of serotonergic projections. Specifically, we examined the influence of in utero ethanol exposure on 5-HT2 binding sites in the motor and somatosensory cortices of the offspring of rats that consumed a control or 6.6% (v/v) ethanol liquid diet on a chronic basis prior to parturition. These studies demonstrated that neither the Kd nor Bmax for the binding of [3H]-ketanserin to membranes from the motor and somatosensory cortices of 19- and 35-day-old rats were significantly altered by in utero ethanol exposure. These results suggest that the development of the postsynaptic target areas of cortical serotonergic projections are more resistant to the effects of in utero ethanol exposure than the presynaptic components of these projections.     

Effects of adolescent ethanol exposure on ethanol consumption in adult rats.

Ethanol exposure during early development could predispose an individual to increased ethanol consumption. Given the high prevalence of adolescent ethanol abuse, it is important to assess the potential impact of adolescent ethanol exposure on the development of alcohol drinking. The following study was designed to assess the initiation of ethanol consumption in adult rats after exposure to ethanol vapors during adolescence. Male Sprague-Dawley rats (n = 23) were exposed to ethanol vapor for 12 h per day for 10 consecutive days between postnatal days 30 and 40. Ethanol vapor exposure maintained blood ethanol levels averaging 250 mg/dl. All rats were subsequently trained to self-administer ethanol after a 52-day withdrawal period. When ethanol consumption was assessed in the adult rats (>3 months old) there were no significant differences in initiation or maintenance of ethanol self-administration between ethanol-exposed and control rats. In addition, there were no group differences in the ability of a noise stressor presented before the drinking session to transiently decrease ethanol intake. Overall, these findings indicate that forced exposure to ethanol vapor during adolescence does not seem to be sufficient to alter initiation or maintenance of limited-access ethanol self-administration.     

Effects of chronic ethanol exposure on sleep in rats.

Sleep disturbance is a common complaint in alcoholics. When polysomnographic studies are performed in alcoholics, reductions in slow wave sleep are a common finding; however, few studies have evaluated the effects of chronic alcohol exposure on sleep in animal models. In the present study, the sleep EEG was evaluated in 40 Wistar rats who were exposed to chronic alcohol or control conditions in vapor chambers. Rats were exposed to ethanol vapors or control chambers for 6 weeks and then withdrawn. Sleep EEG was recorded before exposure (baseline), immediately following exposure, and 5 weeks after withdrawal from the ethanol/control chambers. In the ethanol-exposed animals, blood ethanol levels averaged 192 mg/dL over 6 weeks of exposure. Chronic ethanol exposure and withdrawal was not found to affect either slow wave sleep latency or slow wave sleep duration; however, overall spectral power as well as power in the delta, theta, and beta frequencies were significantly reduced following chronic exposure (2-4 Hz, [F(1, 17) = 18.11, p = 0.001], 4-6 Hz, [F(1, 17) = 15.98, p = 0.001], 6-8 Hz [F(1, 17) = 15.52, p = 0.001], 8-16 Hz band [F(1, 17) = 18.73, p < 0.0001], 16-32 Hz [F(1, 17) = 10.13, p = 0.005], and 1-50 Hz [F(1, 17) = 17.03, p = 0.001]. After 5 weeks of withdrawal, significant decreases still persisted in the delta and theta frequencies (2-4 Hz [F(1, 16) = 6.21, 0.024], 4-6 Hz [F(1, 16) = 6.26, 0.024], and 6-8 Hz [F(1, 16) = 4.84, p = 0.043]). These findings suggest that spectral analysis of the EEG is a highly sensitive measure of the effects of ethanol on sleep. These findings additionally demonstrate that chronic ethanol exposure can produce persistent diminution in the systems that generate cortical slow waves in the rat and thus may provide a model for understanding the mechanisms underlying sleep disturbances associated with alcoholism.     

Effects of adolescent ethanol exposure on sleep in adult rats

Although adolescent ethanol (EtOH) exposure has been associated with long-lasting changes in brain function, little is known as to whether EtOH exposure during adolescence alters sleep and cortical arousal. This study examined protracted alterations in sleep in adult rats exposed to EtOH during adolescence. Adolescent male Wistar rats were exposed to EtOH vapor for 12 h/day for 5 weeks. Cortical electroencephalograms were obtained during 4-h recording sessions after 5 weeks of withdrawal from EtOH. Adolescent EtOH exposure significantly reduced the mean duration of slow-wave sleep (SWS) episodes and the total amount of time spent in SWS in EtOH-exposed rats, compared to controls. Spectral analysis revealed that adolescent EtOH exposure significantly increased cortical peak frequencies during SWS in the 2-4, 4-6, and 6-8 Hz bands. Taken together, our findings suggest that chronic EtOH exposure in adolescent rats reduces measures of SWS, an effect also seen as part of normal aging. Although the cellular and molecular mechanisms mediating the consequences of EtOH exposure on the aging process are not known, the similarities between adolescent EtOH exposure and aging merits further investigation.     

Tianeptine, a specific serotonin uptake enhancer, decreases ethanol intake in rats.

The effect on ethanol intake of the selective 5-HT uptake enhancer tianeptine was examined in rats and compared with that of fluoxetine, a specific 5-HT uptake inhibitor. Both treatments significantly decreased ethanol intake (54% by tianeptine and 57% by fluoxetine). Fluoxetine also decreased food intake whereas tianeptine did not. Body weight was decreased by 12.5% in fluoxetine-treated rats but was not modified by tianeptine. It is proposed that tianeptine has a specific action on ethanol intake, possibly related to its effect on serotonin function.     

Effects of prenatal ethanol exposure on iron utilization in the rat

The effects of prenatal ethanol exposure on iron metabolism in rat dams and pups were studied. Sperm-positive nulliparous dams were assigned to groups on the third day of gestation (G3): ET rats were fed a liquid diet containing 9% ethanol (v/v); PC rats were pair-fed a non-ethanol, isocaloric liquid diet; FC rats were fed the same nonethanol diet adlibitum. All animals were individually housed in stainless steel metabolic cages from G3 to G18 and transferred to polypropylene cages to await delivery. Food intake and dam body weight were significantly less in the ET and PC groups compared to the FC control group. Water intake was significantly greater in the ET dams than in controls. Gestation length was significantly increased in the ET rats only. Pup body weight was significantly decreased in the ET rats only compared to controls. Apparent absorption of iron in the ET dams was significantly greater than in the PC and FC dams. The inutero ethanol exposure resulted in a significant increase in liver and femur iron concentrations in the newborn pups when compared to the PC and FC control pups. The marked increase clue to understanding presence of liver pathology that has been reported to occur in children with fetal alcohol syndrome.     

Effects of prenatal ethanol exposure on ethanol-induced locomotor activity in rats

In adulthood, offspring with Fetal Alcohol Effects exhibit different responses to ethanol than nonexposed offspring; however, the majority of this research has utilized high levels of ethanol prenatally with resultant behavioural and/or physical anomalies. The present research focused on moderate prenatal ethanol exposure and subsequent challenge with low doses of ethanol. Following impregnation, female rats were exposed to between 3-4 g/kg of ethanol in a saccharin solution daily in a voluntary free-choice with water during one of each trimester or during all trimesters. There was a no-ethanol control group which received saccharin only as well as a group of foster dams who drank only water. At 30 days of age, male offspring were tested in an open-field after injection of either 1 g/kg ethanol or a comparable volume of saline. Rats exposed prenatally to ethanol in the second trimester showed enhanced locomotor activity. However, rats exposed prenatally to ethanol in either the first, third or during all trimesters showed no significant augmentation in activity. The results are discussed in terms of the adverse effects of moderate levels of prenatal ethanol exposure on fetal neurochemical development, specifically, the excitatory and inhibitory systems.     

Chronic ethanol exposure leads to divergent control of dopaminergic synapses in distinct target regions

Neuroadaptations following chronic exposure to alcohol are hypothesized to play important roles in alcohol-induced alterations in behavior, in particular increased alcohol drinking and anxiety like behavior. Dopaminergic signaling plays a key role in reward-related behavior, with evidence suggesting it undergoes modification following exposure to drugs of abuse. A large literature indicates an involvement of dopaminergic signaling in response to alcohol. Using a chronic inhalation model of ethanol exposure in mice, we have begun to investigate the effects of alcohol intake on dopaminergic signaling by examining protein levels of tyrosine hydroxylase and the dopamine transporter, as well as monoamine metabolites in three different target fields of three different dopaminergic nuclei. We have focused on the dorsal lateral bed nucleus of the stria terminalis because of the reported involvement of dorsal lateral bed nucleus of the stria terminalis dopamine in ethanol intake, and the nucleus accumbens and dorsal striatum because of their dense dopaminergic innervation. After either a chronic intermittent exposure or continuous exposure regimen, mice were killed, and tissue punches collected from the dorsal lateral bed nucleus of the stria terminalis, nucleus accumbens, and striatum for Western analysis. Strikingly, we found divergent regulation of tyrosine hydroxylase and dopamine transporter protein levels across these three regions that was dependent upon the means of exposure. These data thus suggest that distinct populations of catecholamine neurons may be differentially regulated by ethanol, and that ethanol and withdrawal interact to produce differential adaptations in these systems.     

Chronic intermittent ethanol exposure during adolescence: Effects on social behavior and ethanol sensitivity in adulthood

This study assessed long-lasting consequences of repeated ethanol exposure during two different periods of adolescence on 1) baseline levels of social investigation, play fighting, and social preference and 2) sensitivity to the social consequences of acute ethanol challenge. Adult male and female Sprague-Dawley rats were tested 25 days after repeated exposure to ethanol (3.5 g/kg intragastrically [i.g.], every other day for a total of 11 exposures) in a modified social interaction test. Early-mid adolescent intermittent exposure (e-AIE) occurred between postnatal days (P) 25 and 45, whereas late adolescent intermittent exposure (l-AIE) was conducted between P45 and P65. Significant decreases in social investigation and social preference were evident in adult male rats, but not their female counterparts following e-AIE, whereas neither males nor females demonstrated these alterations following l-AIE. In contrast, both e-AIE and l-AIE produced alterations in sensitivity to acute ethanol challenge in males tested 25 days after adolescent exposure. Ethanol-induced facilitation of social investigation and play fighting, reminiscent of that normally seen during adolescence, was evident in adult males after e-AIE, whereas control males showed an age-typical inhibition of social behavior. Males after l-AIE were found to be insensitive to the socially suppressing effects of acute ethanol challenge, suggesting the development of chronic tolerance in these animals. In contrast, females showed little evidence for alterations in sensitivity to acute ethanol challenge following either early or late AIE. The results of the present study demonstrate a particular vulnerability of young adolescent males to long-lasting detrimental effects of repeated ethanol. Retention of adolescent-typical sensitivity to the socially facilitating effects of ethanol could potentially make ethanol especially appealing to these males, therefore promoting relatively high levels of ethanol intake later in life.     

Treatment with sertraline, a new serotonin uptake inhibitor, reduces voluntary ethanol consumption in rats

Serotonin uptake blockers have been shown to produce a robust and reliable reduction in voluntary ethanol consumption in rats. These compounds are currently under investigation as potential treatments for alcohol abuse in humans. It is uncertain whether serotonin uptake blockers exert their effects directly through serotonergic mechanisms or whether an interaction between the serotonin and noradrenergic systems is involved. The present series of experiments was designed to examine the effects of sertraline, a new selective serotonin uptake blocker, on voluntary ethanol intake. Sertraline produced a robust reduction in voluntary ethanol intake. It appears therefore, that increasing selectivity for serotonin blockade does not alter the efficacy of these compounds as antialcohol agents. The drug also reduced the consumption of a saccharin solution indicating that sertraline's effects are not specific to ethanol intake.     

Effects of periadolescent ethanol exposure on alcohol preference in two BALB substrains.

Ethanol exposure during adolescence is a rite of passage in many societies, but only a subset of individuals exposed to ethanol becomes dependent on alcohol. To explore individual differences in response to ethanol exposure, we compared the effects of periadolescent ethanol exposure on alcohol drinking in an animal model. Male and female mice of two BALB substrains were exposed to ethanol in one of three forms--choice [water vs. 10% (volume/volume) ethanol], forced (10% ethanol in a single bottle), or gradual (single bottle exposure, starting with 0.5% ethanol and increasing at 2-day intervals to 10% ethanol)--from the 6th through the 12th week of age and administered two-bottle alcohol preference tests (10% ethanol vs. water) for 15 days immediately thereafter. All three forms of ethanol exposure increased alcohol preference in male and female BALB/cByJ mice, relative to findings for ethanol-naive control animals. Only gradual ethanol exposure produced an increase in alcohol preference in BALB/cJ mice. During extended alcohol preference testing (for a total of 39 days) of mice in the gradual ethanol exposure group, the higher alcohol preference of the gradual ethanol-exposed BALB/cByJ male mice persisted, but alcohol preference of control group female mice in this strain--formerly ethanol naive, but at this point having received 10% ethanol in the two-bottle paradigm for 15 days--rose to the level of alcohol preference of female mice in the gradual ethanol exposure group. This finding demonstrated that both adolescent and adult ethanol exposure stimulated alcohol preference in female mice of this strain. Across days of testing in adulthood, alcohol preference of the gradual ethanol-exposed BALB/cJ mice decreased, resulting in a lack of effect of gradual exposure to ethanol on alcohol preference in both male and female mice of this strain during the period of extended testing. These strain differences support a genetic basis for the effects of ethanol exposure on alcohol preference and fit within a body of literature, showing substantial individual differences in the effects of ethanol exposure among genetically undefined rats and differences in response to ethanol exposure among inbred rat strains. Exploration of the mechanisms underlying this gene by environment interaction in a mouse model may help elucidate individual differences in the effects of ethanol exposure in human beings and contribute to the understanding of the causes of alcoholism.     

Effects of prior ethanol exposure on ethanol self-administration in a continuous access situation using retractable drinking tubes.

To examine whether exposure to ethanol influences subsequent ethanol consumption using a continuous access procedure, two groups of rats were given differing initial exposure to ethanol. One group underwent a sucrose-substitution initiation procedure. The second group received abbreviated initiation consisting of one-session exposure to each ethanol/sucrose combination used in standard initiation. The animals were then provided with 23 h/day access to ethanol (10%, v/v) from a retractable drinking tube. Food pellets were available following a single-lever press, and water was available from a sipper tube. After 5 weeks, the data indicated that few significant differences existed between the groups on total ethanol (g/kg), food or water consumed. The overall intake (g/kg/day), number of ethanol bouts per day, and amount consumed per bout (g/kg/bout) were substantially lower than observed in previous research using ethanol presented in a dipper. However, differences in g/kg per ethanol bout did differ significantly between the two groups with the group receiving standard initiation showing more ethanol consumed per bout. These data agree with our previous work indicating that initiation results in larger drinking bouts.     

Effects of serotonin uptake blockers and of 5-hydroxytryptophan on the voluntary consumption of ethanol, water and solid food by UChA and UChB rats

The effects of zimelidine, fluvoxamine, and citalopram (serotonin uptake blockers), as well as those of 5-hydroxytryptophan (serotonin precursor), on the voluntary consumption of 10% ethanol solution, distilled water and solid food were tested in UChA (genetically low ethanol consumer) and UChB (genetically high ethanol consumer) rats. Since it is well known that drugs which stimulate central serotonergic synapses decrease food and water intake, the data concerning the difference of the respective consumption during the treatment period and the pretreatment one were analysed with a method previously proposed (Alcohol 5:15-19; 1988) to recognize specific effects on ethanol intake. The results showed that while the decrease of ethanol consumption induced by the three serotonin uptake blockers appeared not to be specific of ethanol, the effects of 5-hydroxytryptophan in UChB rats satisfy the criteria for being considered as an expression of a decrease of the specific appetite--or increase satiety--for ethanol. Experimental results cannot help in the explanation of this difference.     

The use of docosahexaenoic acid supplementation to ameliorate the hyperactivity of rat pups induced by in utero ethanol exposure

It has been demonstrated thatin utero ethanol (EtOH) exposure induces hyperactive behavior and learning disturbances in offspring. In order to investigate the effects of docosahexaenoic acid (DHA) on these neurobehavioral dysfunctions of rat pups induced byin utero EtOH exposure, pregnant Wistar rats were divided into four treatment groups depending on the type of oil added to the diet and drinking water as follows; (a) 5% safflower oil with tap water (TW/n-6), (b) 3% safflower oil and 2% DHA with tap water (TW/n-3), (c) 5% safflower oil with 10%-EtOH (ET/n-6), (d) 3% safflower oil and 2% DHA with 10%-EtOH (ET/n-3) at gestational day (GD) 7. 10%-EtOH was administered to dams in ET/n-6 and ET/n-3 groups from GD 7 to the pups’ weaning (postnatal week 4), and all pups were fed with the same diet that was given to their dams during the entire examination period. The open-field test and the water E-maze test were conducted for all pups, and a spontaneous motor activity test and the Sidman electric shock avoidance test were performed for some of male pups. Amounts of monoamine metabolites in striatum were then determined, and fatty acid analyses of total brain lipids were performed. The male pups in the ET/n-6 group showed significandy more rearing and square-crossing movements in the open-field test, and significandy higher spontaneous motor activity during the dark period in the daily cycle compared to the males in the TW/n-6 group. The male pups in the ET/n-3 group showed fewer of these behaviors in the open-field test compared to the ET/n-6 group males, and a normal pattern of spontaneous motor activity. Learning disturbance induced byin utero EtOH exposure was not observed in the E-shaped water maze, but was observed in the avoidance rates in the Sidman electric shock avoidance test. However, there was no significant modifying effect of DHA on the avoidance rates in EtOH exposed pups. The analysis of the fatty acid composition of total lipids in the brains of the pups revealed high levels of DHA in the diet reflected an increased level of brain DHA and caused a decreased level of the brain arachidonic acid. Retroco nversion from DHA to eicosapentaenoic acid was also observed. However, there was no significant effect of DHA on the levels of monoamine metabolites. These results support the hypothesis that DHA can counteract the attention deficit hyperactivity disorder. This is the secondary publication of the paper entitled, “The effects of docosahexaenoic acid on brain function in rats showing the symptoms of fetal alcohol effects” which appeared in “Alcohol and Biomedical Research” (Alcohol to igakuseibutsugaku [in Japanese]), Tokyo; Toyoshoten. 1997:132-8.     

Effects of chronic ethanol exposure on fatty acids of rat brain glycerophospholipids

The lipid composition was analysed in forebrain subcellular fractions from rats treated with ethanol for three weeks and control rats. Increased proportions of oleic acid and a decrease in palmitic acid were consistently found in total glycerophospholipid fractions after ethanol exposure. The fatty acid compositions of individual phospholipids were also significantly changed. The proportion of docosahexaenoic acid was decreased in brain phosphatidylserine. In contrast to the decrease in the degree of unsaturation in phosphatidylserine, there was an opposite change in phosphatidylcholine wherein the degree of unsaturation was increased. No changes were produced in total cholesterol or phospholipid concentrations. These results point to a high degree of complexity of the mechanisms behind ethanol-induced changes in membrane lipid composition. The decrease in unsaturation in phosphatidylserine is probably an adaptive effect in order to counteract the fluidizing effect of ethanol. There are two possible explanations for the increase in unsaturation in brain phosphatidylcholine. The change may be due to adaptation to other biophysical effects, e.g., expansion of the membrane surface or be secondary to a change in liver lipid metabolism.     

Effects of prenatal ethanol exposure on postnatal renal function and structure in the rat

Effects of prenatal ethanol exposure on postnatal renal function and structure in the rat. Renal function and morphology were studied in 90-day-old offspring of ethanol-fed (E) rats and were compared to pair-fed control (C) animals. Compared to C rats, E rats were smaller at birth, had higher fractional sodium excretion (p less than 0.01) and lower fractional potassium excretion (p less than 0.01). In E rats, sodium (Na) restriction resulted in a significant increase in urine flow and Na wastage, whereas C rats remained in Na balance. E rats developed hyperkalemia, when potassium (K) intake was increased from 2.8 to 14 mEq/day. Baseline creatinine clearance, urine and blood osmolalities and pH, plasma electrolytes and aldosterone concentrations were similar in both groups. There was no significant difference in wet or dry kidney weight, renal water content, or renal tissue concentrations of Na or K between the two groups. No difference was found in gross morphology or light microscopic appearances of the kidneys between E and C rats. Thus rats exposed to ethanol during fetal life have a defect in urine concentration and Na conservation when fed a low Na diet and a defect in K excretion when given a K load without evidence of any gross or light microscopic renal structural abnormalities at 90 days of age.     

Effects of ethanol exposure on neuropeptide-stimulated calcium mobilization in N1E-115 neuroblastoma

The effects of acute and chronic (100 mM for 7 days) ethanol exposures on resting intracellular free calcium, [Ca²⁺]_i, as well as bradykinin and neurotensin mediated [Ca²⁺]_i mobilization were determined in intact N1E-115 neuroblastoma. [Ca²⁺]_i was monitored fluorometrically with the calcium indicator, fluo-3/AM. Acute exposure to ethanol resulted in an inhibition of bradykinin mediated [Ca²⁺]_i mobilization with significant effects observed only at 400 mM ethanol. Neurotensin mediated [Ca²⁺]_i mobilization was not significantly affected by any of the ethanol concentrations tested. Similarly, resting [Ca²⁺]_i (64 ± 2 nM) was unaffected by either chronic or acute ethanol as high as 400 mM. However, chronic exposure to ethanol significantly reduced the magnitude of bradykinin mediated [Ca²⁺]_i mobilization both in the absence and presence of extracellular [Ca²⁺]. In contrast, [Ca²⁺]_i mobilization in the presence of various concentrations of neurotensin was not significantly affected by chronic ethanol exposure. The results suggest that neuropeptide mediated [Ca²⁺]_i mobilization is relatively insensitive to the acute presence of ethanol. In addition, chronic ethanol exposure appears to have selective effects on receptor mediated [Ca²⁺]_i mobilization because this response to bradykinin, but not neurotensin, was significantly reduced in cells exposed to ethanol. The results also suggest that the reduction in bradykinin stimulated [Ca²⁺]_i mobilization in chronically exposed cells is due in part to an inhibition of the release of intracellularly bound [Ca²⁺].     

Effects of in utero and lactational exposure to bisphenol A on thyroid status in F1 rat offspring

Bisphenol A (BPA), a xenoestrogen, has been reported to mimic the actions of estrogen or to affect the endocrine glands in vivo and in vitro. In this study, we examined whether in utero and lactational exposure to BPA alters thyroid status in rat F1 offspring. Dams were orally administered various doses of BPA (0, 4 or 40 mg/kg body weight per day) from gestation day (GD) 6 through postnatal day (PND) 20. The BPA and control groups did not differ significantly with respect to plasma thyroxine (T4) concentration. The thyroid glands from the BPA groups had normal T4 responses to exogenous thyroid-stimulating hormone in vivo. These results suggest that in utero and lactational exposure (indirect exposure) to BPA (4-40 mg/kg/day, GD 6 - PND 20) does not affect thyroid functions in the F1 generation of male and female rats.     

邻苯二甲酸(2-乙基己基)酯孕期暴露对雌性子代大鼠性发育的影响

目的 观察邻苯二甲酸(2-乙基己基)酯(DEHP)对雌性子鼠性发育的影响.方法 妊娠12 d(GD 12)Wistar孕鼠,称重编号,用随机数字表法分为玉米油对照组和1、250、750、1000 mg·kg~(-1)·d~(-1) DEHP染毒组,每组lO只,GD 12～17灌胃染毒.观察雌性子代大鼠出生后第14～17天(PND 14～17)眼睛完全睁开时间;PND 22处死计算脏器系数;PND 30～38观察阴道完全开口时间(若PND 30～38阴道未开口则持续观察至成年期),称量当日体重,并记录首次排卵时间.结果 对照组和1、250、750、1000 mg·kg~(-1)·d~(-1) DEHP染毒组子鼠眼睛完全睁开时间分别为(15.8±0.4)d、(16.3±0.6)d、(16.0±0.6)d、(15.9±0.6)d、(15.8±0.4)d,各组间比较差异无统计学意义(F=1.363,P=0.262).750及1000 mg·kg~(-1)·d~(-1)剂量组部分子鼠阴道永久未开口,未开口百分率分别为62.50%(15/24)、81.25%(26/32),与对照组比较,差异有统计学意义(χ~2值分别为84.92、132.79,P值均<0.01).对照组和1、250、750、1000 mg·kg~(-1)·d~(-1) DEHP染毒组雌性子鼠阴道开口时间分别为(32.7±1.3)d、(33.3±1.5)d、(32.2±1.5)d、(33.1±1.3)d、(33.3±1.2)d;阴道开口时体重分别为(91.56±6.65)g、(93.79±6.28)g、(92.98±8.48)g、(100.57±6.47)g、(103.83±8.24)g.协方差分析显示,修正体重后阴道开13时间各组间比较,差异有统计学意义(F=3.075,P<0.05),其中250 mg·kg~(-1)·d~(-1)组比对照组提前(t=-2.056,P<0.05);体重对阴道开口的影响有统计学意义(F=40.857,P<0.05).结论 GD 12～17 DEHP染毒可影响雌性子代大鼠阴道开口,引发阴道闭锁畸形,导致其性发育异常.