Expression of calbindin-D28k in human fallopian tubes

The present study was aimed at investigating the expression of calbindin-D28k (CaBP-D28k) in human fallopian tube, which were collected from 33 childbearing age women undergoing abdominal hysterectomy with adnexectomy for benign disease in the pelvic cavity. These women had normal menstrual cycle and history of normal pregnancy. Isthmus, ampullary and umbrella segments of fallopian tubes were respectively collected. These specimens were divided into 6 groups based on their menstrual cycles: early-proliferative stage (n=6), mid-proliferative stage (n=5), late-proliferative stage (n=5), early-secretory stage (n=7), mid-secretory stage (n=5) and late-secretory stage (n=5). The expressions of CaBP-D28k protein and mRNA in fallopian tubes were determined by immunohistochemistry and reverse transcription polymerase chain reaction (RT-PCR) methods. Positive expressions of CaBP-D28k protein and mRNA were observed in human fallopian tubes. There was no significant difference in the expression of CaBP-D28k protein among the isthmus, ampulla and umbrella segments in the same phase of menstrual cycle (P>0.05). However, in the menstrual cycle, the expression level of CaBP-D28k protein in the epithelium was the lowest during the early- and mid-proliferative stages and increased in both the late-proliferative and early-secretory stages (P<0.05), and then decreased in the mid- and late-secretory stages (P<0.05). The expressed CaBP-D28k protein was disposed to gobbets or dispersed sheets in cytoplasm in the early- and mid- proliferative stages, and showed concentrated granules on the top of cells in the late-proliferative and early-, mid-secretory stages. Then in the late-secretory stage redistribution renewed as in the early- and mid-proliferative stages. The CaBP-D28k mRNA obviously increased in the late-proliferative and early-secretory stages (P<0.05). These findings indicate that the expressions of CaBP-D28k protein and mRNA exist in human fallopian tubes and exhibit a cyclic change.