Figure 1: A H₂S generation pathway exists in the human fallopian tube.

All data are mean±s.e.m. (a) Representative western blot analysis for CBS and CSE. (b,c) Comparison of the relative CBS or CSE amount expressed in human fallopian tube between the ectopic (n=5) and normal pregnancy groups (n=4). *P<0.05; **P<0.01 versus normal pregnancy group (unpaired t-test). (d,e) Typical immunofluorescence images showing the cellular distribution of CSE (d, red) or CBS (e, red) in a human fallopian tube. Scale bar, 20 μm. Semi-quantitative analysis of immunofluorescence staining shown as the fluorescent pixels per image field. (f) The summaries of the fluorescence densities of CSE and CBS in the fallopian tube epithelium of normal pregnant women (n=16 image fields of eight slices from four samples) and ectopic pregnant women (n=20 image fields of ten slices from five samples). ***P<0.001 versus normal pregnancy ( paired t-test). (g) DAB staining of CBS and CSE in oviduct slices from human. Scale bar, 20 μm. The black arrows indicate the positive staining of the epithelium. (h) Human oviduct homogenate produced H₂S. Incubation of oviduct homogenate with 10 mM L-Cys caused a significant increase in H₂S production compared with basal values (n=11 excised human fallopian tube samples). ***P<0.001 versus basal (paired t-test). PAG (1 mM) or AOAA (1 mM) significantly inhibited the L-Cys-induced increase in H₂S production, whereas SAM enhanced the production of H₂S (n=7–11 excised human fallopian tube samples). ^#P<0.05; ^##P<0.01 versus vehicle (unpaired t-test). The expression of H₂S-synthesizing enzymes CBS and CSE was upregulated in the fallopian tube with an ectopic pregnancy compared with the normal pregnancy (a–g). (i) The production of H2S was increased in the fallopian tube with an ectopic pregnancy compared with the normal pregnancy. n=4–5 excised human fallopian tube samples; ***P<0.001 versus basal conditions (paired t-test); ^#P<0.05 versus normal pregnancy (unpaired t-test).