Background:Methotrexate (Mtx) (the anticancer drug) has been a
prevalent drug in conservative treatment of unruptured tubal pregnancy
for many years. Unfortunately, current emphasis has been focused on the
damaging effects on the ovaries and the fallopian tubes.
Aim of the work:Is to examine the acute and long-term toxic effects of
different doses of MTX on the fallopian tubes.
Materials and methods:The study was carried out on 60 female rats.
The rats were divided into three groups. Control group І(20 rats), group
II (20 rats) Mtx was given to the rats by i.p. injection of 2, 5 mg/kg for
ten days( acute study) and group Ш(20 rats) received(Mtx) 2, 5 mg/kg for
2 months( long term study). Rats in each group were killed at each time
point and the fallopian tubes weredissected and stained H&E and
estrogen receptor (ER) expression was detected by
immunohistochemistry.
Results: Light microscopy (acute) study showed decrease in number of
mucosal folds with fusions of some folds. In small dose, inflammatory
cell infiltration was limited to the mucosa. With increasing the dose,
cellular infiltration extended to musculosa & serosal layer. In chronic
study with small dose there was improvement in some regions as
epithelial folding and muscle layer with decrease in inflammatory cell
infiltration. Immunohistochemical study revealed significant decrease of
estrogen receptors immunoreactivity inepithelial cells in acute and
chronic (high dose) groups while, in chronic study (low dose) significant
increase of estrogen receptors immunoreactivity was detected.
Conclusion: These results provide that long-term MTX (_>5 mg/kg) can
induce irreversible damage to fallopian tubes and steroid hormone
receptors (ER) in a dose-dependent manner. So MTX should be used in a
relatively small dose and short duration in order to avoid impairment in
tubes and potential risk of subsequent tubal pregnancy or infertility.