[Gender-dependent Expression of ERß in AEC â ¡ of Fetal Mice Exposed to Arsenic and Estrogen Receptor Antagonist].

OBJECTIVE: To determine the effects of arsenic and estrogen receptor antagonist (ICI182, 780) on the expression of estrogen receptor beta (ERß) in alveolar Ⅱ epithelial cells (AECⅡ) of female and male mice. METHODS: Nineteen or twenty day fetus mice were obtained through caesarean section of ICR mice. Purified AECⅡ cells were separated from the female and male fetus,respectively,and confirmed using immunofluorescence staining. The cells were exposed to sodium arsenite (NaAsO2) at a low,medium,or high dosage determined by MTT and cultured for 24 h. The NaAsO2 (5 µmol/L) exposed cells were compared with those treated (for 24 h) with dimethyl sulfoxide (DMSO) or ICI182, 780 (1×10-4 mol/L). Apoptosis rates of the cells were measured by flow cytometry. Real-time fluorescence quantitative PCR method and Western blot technique were used to detect the expression ofERßmRNA and protein in AECⅡ. RESULTS: Purity of AECⅡ cells reached (87.0±2.5)%. NaAsO2 exposure was set at a concentration of 0.5 (low),1.25 (medium),and 5 (high) µmol/L. The cells exposed to medium and high dosage of NaAsO2 had higher apoptosis rates than the blank controls (P<0.05),without sex differences. Female cells exposed to medium and high dosage of NaAsO2 had higher levels of expressions ofERßmRNA and protein than the blank controls (P<0.05) and male cells exposed to the same dosage of NaAsO2 (P<0.05). No significant differences were found in the expressions ofERßmRNA and protein between the exposed male cells and the blank controls. ICI182, 780 lowered the expression levels ofERßmRNA and protein in the female exposed cells (P<0.01). CONCLUSION: Arsenic exposure increases expressions of AECⅡ's ERß,more so in female cells than in male cells. This can be blocked by estrogen receptor antagonists.

[Identification of the meiotic events in grasshopper spermatogenesis].

The grasshoppers are ideal materials to study various meiotic stages of spermatogenesis due to their easy availability, fairly large chromosomes, and fewer numbers of chromosomes. It is easy to make temporary squash preparation of grasshopper testes; however, it is usually difficult for the beginners to differentiate between stages of meiosis. In view of this, we demonstrated the method of identification of meiotic stages by chromosome number and chromosome conformation, taking spermatogonial meiosis of Locusta migratoria manilensis as an example. We described briefly the mitosis of spermatogonia and the spermatogenesis of this species as well.