Effect of methotrexate and leucovorin on female reproductive tract of albino rats.

Methotrexate (MTX) an antifolate drug and leucovorin its antidote, are used in the treatment of both neoplastic and non-neoplastic diseases in young women. We hypothesize that MTX treatment might comprise a deleterious effect on fast proliferating reproductive cells, an unavoidable and unwanted side effect. MTX given dose dependently to rats for 20 days prevented vaginal cyclicity and caused a reduction in serum progesterone and estradiol. External morphology of reproductive tract displayed thinning of organs and reduction in their weights. To reveal mechanism of MTX action, we examined the histology of ovary, oviduct, uterus, cervix and vagina. Results suggested that in a dose-dependent fashion MTX restrained preantral and antral follicular growth in ovary. Epithelium and stroma of oviduct, uterus, cervix and vagina were disrupted and lost their normal structures. Such alterations in ovarian function raised serum follicle stimulating hormone, luteinizing hormonal profiles. Expression of steroidogenic acute regulatory protein and P450 cholesterol side chain cleavage gene, which are both essential for steroidogenesis, markedly decreased in ovary upon MTX treatment. Total RNA, DNA and protein concentrations, glucose 6 phosphate dehydrogenase, lactate dehydrogenase and alkaline phosphatase enzyme activities in ovary were distinctly altered. Leucovorin supplementation and withdrawal of the treatment, improved MTX caused effects partially. These results for the first time indicate that the malfunction of female reproductive organs by MTX treatment in young women is not only correlated to the disrupted circulating levels of hormones and histoarchitecture of tissues but also discrepancies in steroidogenic genes and hormone regulated enzyme activities in ovary.

Reproductive and developmental effects of transovarian exposure to o,p'-DDT in Japanese quails.

Avian species have the possible risk of embryonic exposure to persistent, lipophilic environmental contaminants, such as dichlorodiphenyltrichloroethane (DDT), by transfer of chemicals accumulated in mother birds to eggs. To model developmental and reproductive disorders of wild birds living in contaminated areas, we exposed Japanese quails in ovo to o,p'-DDT prior to incubation. A positive estrogenic substance diethylstilbestrol (DES; 1 and 10 ng/g of egg) and o,p'-DDT (1-100 microg/g of egg) were injected into the yolk before incubation. Treatment with o,p'-DDT (10 or 100 microg/g) but not with DES significantly reduced the hatchability of eggs. After sexual maturation, o,p'-DDT affected eggshell formation in female quails but had little influence on laying; high doses of o,p'-DDT significantly reduced eggshell strength, shell weight, and shell thickness, and several females treated with 100 microg o,p'-DDT/g laid eggs lacking shells. Diethylstilbestrol decreased egg production itself but had little effect on the eggshell. Both o,p'-DDT and DES caused dose-dependent shortening of the left oviduct and abnormal development of the right oviduct in females, while testis asymmetry was observed in males treated with a high dose of DES. In the uterus of the oviduct, the mRNAs for calcium-regulating factors osteopontin and calbindin D28K were reduced by both treatments, particularly that with o,p'-DDT. The results indicated that transovarian exposure to o,p'-DDT could bring about population declines in avian species through loss of fecundity caused by depression of hatchability and dysfunction of the reproductive tract.