| ObjectiveFormaldehyde is one of the major indoor pollutants, the health effects of formaldehyde are irritating to eyes, nostril and upper respiratory mucous lining and allergic, mutation, carcinogenic and its effects on reproductive, nerve and immune systems. In order to elucidate the effects of formaldehyde on reproduction and genetics, the activities of cell enzyme in testicle, concentration of testosterone in serum were measured, apoptosis of testicle reproductive cells and their cross-link with DNA were detected, the process of sperm development in male mice and damages formaldehyde did to testicle were also observed. The micronuclear test of liver cells from embryo mice and dominant lethal test were conducted to determine the effects of formaldehyde on offspring.Methods60 male and 120 female healthy Kunming mice were purchased from animal center of XinMin faculty. Body weight of the mice is(15±2)g. The mice were classified into negative control randomly, formaldehyde exposed group, and positive control group,exposed dose was 21mg/m3(1/24LC50), 42mg/m3 (1/12 LC50), 84mg/m3 (1/6 LC50). 12 male mice and 24 female mice were included in each group. Male mice from negative control, mice from different formaldehyde exposed groups inhaled formaldehyde at 2h/d, 6d/w for 13w. Mice in positive control were injected with CP consecutively for 5d. Mice in negative control inhaled air, mice in positive control were injected with cyclophosphamide(50mg/kg)in belly. On day three after exposure completion, male and female mice were roomed together with male 1 and female 2. Testosterone concentration in serum and enzyme activities of testicle cells were measured. Cell cycle, apoptosis of testicle cells and its cross-link with DNA were tested. Aberration ratio of mice sperm and pathological changes were observed under microscope. On day 16 after the female mice were pregnant, the female mice were sacrificed and their offspring were examined, pregnancy rate of female mice, live embryo and micronuclei rate of liver cells from embryo mice were calculated. Statistics analyses of quantitative data were conducted using variance analyses. Categorical data were analyzed by Chi-square test.Results1. Effects of formaldehyde on the testicle weight of male mice: Testicle index decreased in 1/24LC50 and 1/12LC50 group while testicle index increased in 1/6LC50 group, there is no significant differences compared with negative control group(p>0.05). 2. Effects of formaldehyde on the enzyme activities of testicle cells in mice: The activities of LDH, G-6-PD, SDH in testicle cells from mice in different exposed dosage group decreased with the increasing of exposed dosage, The activities of LDH and SDH in testicle cells from mice in 1/12LC50 and 1/6LC50 group, G-6-PD activities in testicle cells from mice in 1/6LC50 group were significantly low compared to negative control group.(p<0.05 or p<0.001).3. Effects of formaldehyde on cell cycle and apoptosis of testicle cells in mice: The cell percentages of G0/G1 and G2+M phase with the increasing of formaldehyde exposed dosage, while the cell percentage of S phase increased. the cell percentage of G0/G1 and G2+M phase from 1/6LC50 group were significantly lower than the other dosage groups. The cell percentage of S phase from 1/6LC50 was significantly different from that o f negative control. The apoptosis rate of testicle cells increased with increment of formaldehyde dosage. The apoptosis rate in 1/6LC50 group was higher than all the groups significantly.4. Effects of formaldehyde on DNA cross-link of spermatogonia in mice: There is no significant differences in the ratio of spermatogonia having tail and the length of tail among exposed and control groups.5. Pathologic changes of testicle tissue in mice: The seminiferous tubule were damaged from mice in exposed group, secondary spermatocytes were turgidited and denaturalized and matured spermatocyte denaturalize low-grade in 1/24LC50 and 1/12LC50 groups。Especially in mice from 1/6LC50 group,th... |
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