Study On Mechanism Of Reproductive Toxicity Induced By Octylphenol On Male Rat

In recent years, scientists have been concerned for disrupting effects of environmental chemicals on reproductive and endocrine system. During the past fifty years, occurrence rate of abnormal development of male reproductive system had increased by more than one time and the sperm quantity had decreased by near fifty percent. Researches showed that male fertility and reproductive disease were both closely related to environmental endocrine disruptors (EEDs). Among the confirmed EEDs, alkylphenol ethoxylates (APEs) and its degradation products have been paid more and more attention due to their widely pollution in the environment. Currently, APEs is the second commercial non-ionic surfactants in the world among which eighty percent is nonylphenol ethyoxylates (NEPs), fifteen percent is octylphenol ethyoxylates (OPEs). Octylphenol (OP) is the main metabolite of OPEs in the environment and can be utilized in the production of detergents, oil additive and so on. In the domestic market, OP is large-scale used in the production of wall coats of milk bottles, cans, plastic food bags and cosmetics etc. The output of OP in the world is about three hundred thousand tons every yearand in China is about five thousand tons every year. With the industrialization development, the contamination caused by OP has threatened humankind health. It is imperative to carry out a comprehensive study on potential harm of OP. The half life of OP in the environment is very long. Human body can be exposed to it via the food and biology chain which in end do harm to human health. OP was reported to be the most potent estrogenic alkylphenol in the yeast assay in vitro with the estrogenictity being approximately 1/1000 of estrogen 17β -estradiol (E₂). Studies suggested that OP could induce toxicity on reproductive and development systems.This thesis is aimed to explore reproductive toxicity of OP to male and its relative mechanisms by in vivo and in vitro studies. Hopefully, it will help to elucidate the potential harm of OP to human health.Part â… : Studies on the effects of OP to the reproductive and endocrine system of male rat and its mechanismsIn order to explore the toxicity of OP to male reproduction and possibility of endocrine disrupting mechanisms, adult male Sprague Dawlay rats were divided into four groups randomly. OP dissolved in corn oil was administered by gavage at doses of 0, 50 150 and 450mg/(kg·d) for six mornings every week. After four consecutive weeks (two period of spermiogenesis), the rats were killed and testis, viscera and sera were taken out. According to the different projects, we stored them separately. The main results are as follows:1. With the dose of administration increased, the weight of rats trended to increase slowly. From control group to high dose group, the weight of rats decreased gradually. Compared with control group, the average weight of 450mg/(kg·d) group displayed significant decrease.2. The absolute and relative weights of epididymis, prostate and spermatophore declined in a dose-dependent manner, especially theweights of 450mg/(kg-d) group declined significantly. The absolute weights of testes also declined, especially 450mg/(kg-d) group weights declined significantly as compared with control group. However, the relative weights of testes in 450mg/(kg-d) group were significantly higher than those of control group. Moreover, the absolute and relative weights of kidney in 450mg/(kg-d) group increased significantly.3. The sperm head count (SPC) and daily sperm production (SPR) declined in a dose-dependent manner, especially SPC and SPR of 450mg/(kg-d) group decreased significantly.4. With the dose of administration increased, ALP showed declining trend, especially 450mg/(kg-d) group showing significant decline. No any significant difference of ACP, LDH, y-GT, G-6-PDH and SDH levels was among the different groups.5. The motility of rat sperm in epididymidis was changed by OP. LIN, VSL and STR declined with the increased dose of administration, and LIN of 450mg/(kg-d) group was significa...