Evaluation of reproductive toxicity in rats caused by organic extracts of Jialing River water of Chongqing, China

Experimental comparison of the reproductive outcomes and early development of the offspring of rats given five common types of drinking water

Tap water (unfiltered), filtered tap water and processed bottled water (purified water, artificial mineralized water, or natural water) are now the five most widely consumed types of drinking water in China. However, the constituents (organic chemicals and inorganic ingredients) of the five waters differ, which may cause them to have different long-term health effects on those who drink them, especially sensitive children. In order to determine which type of water among the five waters is the most beneficial regarding reproductive outcomes and the developmental behaviors of offspring, two generations of Sprague–Dawley rats were given these five waters separately, and their reproductive outcomes and the developmental behaviors of their offspring were observed and compared. The results showed that the unfiltered tap water group had the lowest values for the maternal gestation index (MGI) and offspring's learning and memory abilities (OLMA); the lowest offspring survival rate was found in the purified water group; and the highest OLMA were found in the filtered tap water group. Thus, the best reproductive and offspring early developmental outcomes were found in the group that drank filtered tap water, which had the lowest levels of pollutants and the richest minerals. Therefore, thoroughly removing toxic contaminants and retaining the beneficial minerals in drinking water may be important for both pregnant women and children, and the best way to treat water may be with granular activated carbon and ion exchange by copper zinc alloy.

The combined toxicity of dibutyl phthalate and benzo(a)pyrene on the reproductive system of male Sprague Dawley rats in vivo

Our previous studies revealed more than 100 pollutants, most of which were endocrine disruptors (EDs) in two Chinese rivers, the Jialing and the Yangtze near Chongqing. Most EDs, such as dibutyl phthalate (DBP) and benzo(a)pyrene (BaP), are known to act individually as reproductive toxicants. However, little is known about the combined toxicity of DBP and BaP. In the current study, male Sprague Dawley rats were subchronically exposed to single doses of DBP (250 mg/kg), single doses of BaP (5 mg/kg) and combined doses of DBP and BaP. Significant adverse effects were observed on the reproductive system, including decreased sperm count, increased production of abnormal sperm, changes in serum testosterone levels and irregular arrangements of the seminiferous epithelium. Biochemical analyses showed that the activities of superoxide dismutase and glutathione peroxidase decreased after exposure to these EDs. Therefore, our data suggest that exposure to DBP and BaP, in either separate or combined doses, can affect the reproductive system of male rats adversely via oxidative stress-related mechanisms. No significant additive effect was observed after combined exposure. These results indicate that exposure to mixtures of EDs have unexpected and elusive effects. Our findings provide preliminary but important data for assessing water safety in China.

Male reproductive and behavior toxicity in rats after subchronic exposure to organic extracts from Jialing River of Chongqing, China

BACKGROUND

More than 100 species of organic chemicals have been detected in Jialing River of Chongqing City. Most of them are endocrine-disrupting chemicals (EDCs), which can disrupt the functions of the reproductive and nervous systems.

METHODS

Organic extracts (OE) were obtained by solid extraction from the Jialing River, and administrated to rats by gavage every other day for 13 weeks at doses of 2, 12, and 72 L/kg bw/d. Sperm abnormity was analyzed by microscopy and flow cytometry. The Morris water maze task was employed to investigate the behaviors of space probing. Activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) content were measured to detect the peroxidation response in hippocampus and testis.

RESULTS

Animals in the 72-L/kg group showed significant degeneration of germ cells in the seminiferous tubule. Sperm abnormality of the 72-L/kg group was significantly higher than that of the solvent control group. The testis oxidative stress in the 72-L/kg group was severer than that of the other groups. The hippocampus neuron cells in the 72-L/kg group showed cellular edema and remarkable cell enlargement. The hippocampus oxidative stress in the 72-L/kg group was severer and the Morris water maze performance in this group showed longer latency time and swimming distance in the probing platform than the other groups.

CONCLUSIONS

OE caused pathological damage and peroxidation response to testis and hippocampus and disrupted spermatogenesis and behavior of space probing.

Evaluation of ovotoxicity in female mice caused by organic extracts in tap water from Jialing River in Chongqing, China

BACKGROUND

Recently, toxic effects of widespread organic pollutants have received much attention due to the hazards they pose to female reproductive health. The aim of the present study was to determine the female reproductive toxicity of organic extracts (OE) in tap water from the Jialing River in Chongqing, China.

METHODS

In our experiment, Kunming female mice that exhibited normal estrous cycles were randomly divided into 4 groups, which included a control group (OE 0 L/kg bw) as well as low- (OE 12.5 L/kg bw/day), mid- (OE 25 L/kg bw/day), and high-dose (OE 50 L/kg bw/day) groups. Mice were continually administered intraperitoneal injections of OE at different doses for 5 consecutive days. On the 15th and 30th day after treatments, half of the mice were sacrificed separately.

RESULTS

The results showed that OE decreased relative ovary weights and prolonged the duration of estrous cycle with concomitant increase in estrous phase. There was a significant decrease in the number of corpora lutea of OE-treated mice, but no significant differences were found in healthy and atretic follicle populations compared to control. Ultrastructure observation regarding granulosa cells of the ovary revealed that OE treatment caused mitochondrial swelling together with endoplasmic reticulum expansion.

CONCLUSIONS

All these data indicate that OE could exert adverse effects on the development of ovary and also a slight suppressive effect on reproductive functions.