Michael W. Church

Dose-dependent consequences of cocaine on pregnancy outcome in the Long-Evans rat

The number of obstetric patients abusing cocaine has increased dramatically in recent years. To better understand its effect on pregnancy and to establish the LD50s for maternal and fetal fatalities, the dose-dependent effects of cocaine on pregnancy outcome were investigated in the Long-Evans rat. Pregnant animals were given either saline or 40, 50, 60, 70, 80, or 90 mg/kg cocaine hydrochloride from gestation days 7 to 19 inclusive. An additional group was non-treated and had ad lib access to food and water. Animals were sacrificed on gestation day 20 and the fetuses were examined. Despite treatment during the major periods of organogenesis and brain development, few congenital abnormalities were observed. There were, however, dose-dependent effects on maternal weight gain, maternal food and water consumption, fetal weight, maternal and fetal fatalities, fetal edema, abruptio placentae and cephalic hemorrhages. Despite suppression of maternal weight gain, there was preservation of fetal weights at cocaine doses up to and including 80 mg/kg/day, suggesting some protection of fetal growth. In addition to providing information on the gestational effects of cocaine in the rat, the present study provides information useful in guiding the selection of cocaine doses for subsequent behavioral teratology studies.

Prenatal cocaine exposure in the Long-Evans rat: II. Dose-dependent effects on offspring behavior

Pregnant Long-Evans rats were injected daily with 40, 60, 80 or 100 mg/kg cocaine HCl (SC, 2% solution) from gestational days 7-20 (sperm positive = day 0). Daily doses were split with half given between 9:00-10:00 a.m. and half between 3:00-4:00 p.m. An ad lib-fed group as well as nutritional control groups that were pair-fed to the 80 and 100 mg/kg cocaine dams were also evaluated (N = 11-18 litters/group). The negative geotactic reaction of the offspring, evaluated from day 2-14 (birth = day 0), showed no group differences. Spontaneous alternation behavior in a T-maze showed no evidence of perseveration in any group on either day 21 or day 80. Most cocaine-treated offspring showed an altered preference in turning right versus left on day 21. Activity monitor behavior showed that the cocaine-treated and pair-fed offspring were hypoactive on day 20. Some degree of hypoactivity was still evident on day 49, but absent on day 80. The passive avoidance behavior of day 19 offspring showed no group differences in acquisition of task learning. The 100 mg/kg cocaine offspring did show significantly poorer retention of task learning 48 hr later. On day 80, no group differences were seen in passive avoidance behavior. Acquisition of an active avoidance behavior on day 80 was significantly poorer in the 100 mg/kg cocaine group.

Prenatal cocaine and alcohol exposures affect rat behavior in a stress test (The Porsolt Swim Test)

Prenatal cocaine and alcohol exposures have been associated with a variety of adverse effects ranging from subtle neurobehavioral abnormalities to major malformations. In this study, we used the Porsolt swim test to assess the effects of prenatal cocaine and alcohol exposures on stress-related behavior. Pregnant Long-Evans rats were injected daily with 80 mg/kg cocaine HCl (SC) or 6.2-6.5 g/kg ethyl alcohol (PO) from gestation days 7-20 with half the dose given in the morning and the other half in the afternoon. Pair-fed and ad lib control groups were also used. One male offspring from each litter was evaluated in the Porsolt swim test at the age of 120 days. The alcohol and cocaine groups were less immobile (i.e., struggled more to escape) than the controls. These results suggest that prenatal exposure to either alcohol or cocaine can adversely affect behavior in stressful or fearful situations.

Prenatal cocaine exposure in the Long-Evans rat: I. Dose-dependent effects on gestation, mortality, and postnatal maturation.

Pregnant Long-Evans rats were injected daily with 40, 60, 80, or 100 mg/kg cocaine HCl (SC, 2% solution) from gestational days 7-20 (sperm positive = day 0). Daily doses were split evenly with half given between 9:00-10:00 a.m. and half between 3:00-4:00 p.m. An ad lib-fed group as well as nutritional control groups that were pair-fed to the 80 and 100 mg/kg cocaine dams were also evaluated (N = 11-18 liters/group). Cocaine had no effect on gestational length but did cause dose-dependent decreases in maternal food consumption and weight gain and increases in maternal mortality. Interestingly, cocaine-treated dams shows a significant increase in water consumption. In terms of offspring variables, there was a dose-dependent decrease in birth weight and postnatal weight gain in both the cocaine and pair-fed groups. There were also dose-dependent effects on litter size, stillbirths and postnatal mortality in the cocaine-treated groups as compared to the control groups. High dose cocaine treatment caused delays in several indices of physical maturation (pinna detachment, fur growth, ear opening, eye opening, vaginal opening) but not in others (incisor eruption, testicular descent). Physical anomalies and postnatal morbidity, while uncommon, were observed in animals prenatally exposed to the higher cocaine doses. Collectively, these data suggest that prenatal cocaine exposure can increase postnatal morbidity as well as increase pre-and postnatal mortality in animal offspring.

The comparative effects of sodium thiosulfate, diethyldithiocarbamate, fosfomycin and WR-2721 on ameliorating cisplatin-induced ototoxicity

The efficacies of four agents in ameliorating cisplatin-induced ototoxicity were investigated. Hamsters were given a series of 5 cisplatin injections (3 mg/kg/injection once every other day, i.p.) either alone or in combination with 1600 mg/kg/injection sodium thiosulfate (STS), 300 mg/kg/injection diethyldithiocarbamate (DDTC), 18 mg/kg/injection WR-2721, or 300 mg/kg/injection fosfomycin (n = 10/group). Ototoxicity was assessed electrophysiologically by auditory brainstem responses (ABRs) and anatomically by cochlear histology. The greatest auditory protection was given by STS, followed by DDTC. WR-2721 and fosfomycin did not provide any protection. All of the animals in the STS and DDTC groups survived, while some fatalities occurred in the fosfomycin, WR-2721, and cisplatin-only groups. Thus, the agents that were protective against ototoxicity were also protective against mortality. The ABRs also provided evidence of cisplatin-induced neuropathy. In summary, STS and DDTC hold promise for ameliorating the ototoxic effects of cisplatin chemotherapy and the hamster proved to be an excellent model of cisplatin ototoxicity.

Interactive effects of prenatal alcohol and cocaine exposures on postnatal mortality, development and behavior in the Long-Evans rat

Polydrug abuse has increased substantially in recent years amongst obstetric patients. One of the most common drug combinations is alcohol and cocaine. To better understand the adverse consequences of this drug combination on pregnancy and the offspring, alcohol (2 g/kg, b.i.d.) and cocaine HCl (30 mg/kg, b.i.d.) were administered individually and in combination to separate groups of pregnant Long-Evans rats from gestation days 7-20. The pregnant dams were evaluated for maternal weight gain, food and water consumption, mortality, and gestational length. The offspring were evaluated for physical maturation, mortality, and behavior. The drug combination was found to have greater effects regarding decreased birth weight, increased postnatal mortality, and delayed physical maturation than either drug alone. Drug treatments also influenced activity monitor behavior in that prenatal cocaine exposure was associated with hypoactivity while the alcohol and the alcohol-plus-cocaine treatments were associated with hyperactivity in periweanling pups. Drug treatments had no significant effects on passive or active avoidance behaviors. These results suggest that combining alcohol and cocaine increases the risk to the offspring.

The interactive effects of alcohol and cocaine on maternal and fetal toxicity in the Long-Evans rat

The number of obstetric patients with polydrug abuse problems has increased substantially in recent years. One of the most common drug combinations is alcohol and cocaine. The effect of this drug combination on pregnancy is, therefore, of interest. Consequently, the present study investigated the relative and interactive effects of these two drugs on pregnancy outcome in an animal model. Alcohol and cocaine were administered, both separately and in combination, to separate groups of pregnant Long-Evans rats from gestation day 7-19. Animals were then sacrificed and examined on gestation day 20. Control animals were given vehicle only or were nontreated. The isobolographic method was used to evaluate the effects of the alcohol-by-cocaine interaction on select maternal and fetal variables. This method of analysis indicated that alcohol and cocaine had interactive effects that were linearly additive for some variables and infraadditive for others. In general, the results suggest that the alcohol-plus-cocaine drug combination poses a greater risk to pregnancy than either drug alone.

Comparison of five agents in protecting the cochlea against the ototoxic effects of cisplatin in the hamster

The purpose of this investigation was to study the ameliorating effects of four agents on cisplatin-induced ototoxicity. Hamsters were given a series of five cisplatin injections either alone or in combination with sodium thiosulfate (STS), diethyldihydrothiocarbamate (DDTC), and S-2(3-aminopropylamino) ethylphosphorothioic acid (WR-2721), or fosfomycin. Ototoxicity was assessed anatomically by quantifying the extent of cochlear damage with the scanning electron microscope and physiologically with measures of the auditory brain stem response. When administered alone, cisplatin induced widespread loss of outer hair cells (OHCs) along much of the cochlea in the hamster, especially in the basal and middle turns, with an average survival of only 56% of the OHC population. In contrast, inner hair cells resisted cisplatin ototoxicity in the hamster. Thus the ameliorative effects of the different test agents were assessed by counting the number of surviving OHCs in each treatment group and comparing with cisplatin-treated controls. STS provided the most effective protection against the ototoxic effects of cisplatin, yielding 91% survival of OHCs. DDTC also reduced the ototoxic effects of cisplatin, yielding 68% survival of OHCs. Cotreatment with WR-2721 and fosfomycin yielded 45% and 52% OHC survival, respectively, and thus did not provide any chemoprotection. The results closely paralleled those based on auditory brain stem response recordings in that the magnitude of threshold shift was proportional to the amount of OHC loss; also, the amount of threshold shift at each frequency was in good agreement with the pattern of hair cell loss along the cochlear spiral. Thus both histologic and physiologic results suggest that STS and DDTC hold promise for ameliorating the ototoxic effects of cisplatin chemotherapy.

Excess and deficient omega-3 fatty acid during pregnancy and lactation cause impaired neural transmission in rat pups

Omega-3 fatty acids (omega-3 FA) consumption during pregnancy and lactation is beneficial to fetal and infant growth and may reduce the severity of preterm births. Thus, scientists and clinicians are recommending increasingly higher omega-3 FA doses for pregnant women and nursing babies for advancing the health of preterm, low birth weight, and normal babies. In contrast, some studies report that over-supplementation with omega-3 FA can have adverse effects on fetal and infant development by causing a form of nutritional toxicity. Our goal was to assess the effects of omega-3 FA excess and deficiency during pregnancy and lactation on the offsprings neural transmission as evidenced by their auditory brainstem responses (ABR). Female Wistar rats were given one of three diets from day 1 of pregnancy through lactation. The three diets were the Control omega-3 FA condition (omega-3/omega-6 ratio approximately 0.14), the Deficient omega-3 FA condition (omega-3/omega-6 ratio approximately 0%) and the Excess omega-3 FA condition (omega-3/omega-6 ratio approximately 14.0). The Control diet contained 7% soybean oil, whereas the Deficient diet contained 7% safflower oil and the Excess diet contained 7% fish oil. The offspring were ABR-tested on postnatal day 24. The rat pups in the Excess group had prolonged ABR latencies in comparison to the Control group, indicating slowed neural transmission times. The pups in the Excess group also showed postnatal growth restriction. The Deficient group showed adverse effects that were milder than those seen in the Excess group. Milk fatty acid profiles reflected the fatty acid profiles of the maternal diets. In conclusion, excess or deficient amounts of omega-3 FA during pregnancy and lactation adversely affected the offsprings neural transmission times and postnatal thriving. Consuming either large or inadequate amounts of omega-3 FA during pregnancy and lactation seems inadvisable because of the potential for adverse effects on infant development.

FETAL ALCOHOL SYNDROME: Hearing, Speech, Language, and Vestibular Disorders

Fetal alcohol syndrome (FAS) refers to a pattern of anomalies that include craniofacial, CNS, growth, and various sensory anomalies. We have observed that FAS is associated with four kinds of hearing disorders: (1) developmentally delayed auditory function, (2) sensorineural hearing loss, (3) intermittent conductive hearing loss owing to recurrent serous otitis media, and (4) central hearing loss. As is the case with other syndromes associated with craniofacial anomalies and hearing impairments, speech and language pathologies also are common in FAS patients. Although auditory and vestibular systems arise from similar embryological tissue, vestibular dysfunction is variable in FAS. Early identification and intervention to treat hearing, language, and speech problems should improve the functional level of FAS in children.