| Fluorine (F) is one of the nonmetal trace elements which are indispensable to organisms. Having strong electronegative, fluorine widely exists in the environment by fluoride. Appropriate fluoride is beneficial to prevent caries, to maintain nerve transmission, as well as to support calcium and phosphate of organisms. And yet, excessive intake of fluoride produces potent toxicity to some systematical function of organisms. In previous researches, importance was attached to the damage of skeletal tissue by fluorine. But with fluoride's extensive application in industry, agriculture, and daily life, recent researches pay more attention to the nonskeletal toxicity of fluorine. Meanwhile, with the progress of study, it was found that male infertility rate in high fluoride exposed area was greatly higher than that of low fluoride exposed area, and that the quality and quantity of sperm all reduced significantly. So, studies on male reproductive toxicity induced by fluoride were attached more importance recently.Spermatogenic cell apoptosis appears during spermatogenic cycle normally. During spermatogenesis, 25 to 75 percent of total spermatogenic cells theoretically produced were lost by form of apoptosis. Apoptosis can be triggered at specific stages of cell's maturity, and happens during the whole spermatogenesis to regulate the balance of spermatogenic cell death and proliferation, as well as to mediate theinvariance of spermatogenic cell both in quality and quantity. A large proportion of spermatogenic cells in seminiferous tubule apparently degenerate during spermatogenesis, which forms a possible critical regulator to testis both physiologically and in pathological conditions. As to experimental studies on spermatogenic cell apoptosis and its mechanism induced by fluoride, few researches were performed. So, researches on effect to spermatogenic cell apoptosis caused by fluoride are valuable both in the deep investigation on the mechanisms of fluoride's male reproductive toxiticy, as well as the early index of male reproductive health inspection and surveillance of fluoride exposure person. Materials and methods1. Thirty healthy male Wistar rats weighted 110 to 130 gram were allocated into six groups randomly. There were five rats in every group. The six experimental groups were 28-day control group, 28-day low-dose fluoride treatment group, 28-day high-dose fluoride treatment group, 38-day control group, 38-day low-dose fluoride treatment group, and 38-day high-dose fluoride treatment group. The NaF dosage for control, low-dose fluoride treatment, and high-dose fluoride treatment group were 0, 1 0, and 20 mg/kgBw/2d, respectively.2. According to the above-mentioned experimental dose and duration, every fluoride treatment group was subcutaneously injected with NaF solution once two days to establish fluorosis rat model. While the control rats were injected with saline. At the end of the experiment, after putting the rat to death both testis and epididymide were dissected out and weighted for calculating their organic coefficient. The content of NaF in testis was measured by using fluorine selective electrode. The testosterone (T) and estradiol (E2) contents in serum were radioimmunochemically detected to explain the mechanisms of spermatogenic cell apoptosis and its relation to fluorosis. The pathological alterations of testis were observed with light microscope for the order, shape, and structure of cells in spermatogenic epithelium. The apoptotic spermatogenic cells were quantitatively measured by TdT-mediated dUTP nick end labelin (TUNEL) method in situ.3. One-way analysis of variance (ANOVA), independent-samples T test, as wellas linear correlation analysis were used in the statistical test. There was significantdifference when a was 0.05.Results1. As to body weight, testis weight, epididymide weight and their organic coefficient, except the testicular organic coefficient and epididymide weight, significant differences were observed about the other three index when 28-day high-d... |
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