Reduced TRPV1, Kir6.1/SUR2B, and eNOS expression in severe
preeclampsia
The localization of the TRPV1,
Kir6.1/SUR2B, and eNOS channels was evaluated in placental arterioles by
immunohistochemistry (Fig. 3), and the results showed that each channel
was mainly distributed in the
vascular endothelial layer. It was noted that the counterstained nuclei
in the endothelial cell layer was significantly decreased, as was
membrane staining of each channel in the SP group compared with the NP
group. The optical densities of TRPV1, Kir6.1/SUR2B, eNOS in the SP
group were 11660.0±1721.0, 2975.0±505.5, 10236.0±1355.0, 14663.0±2320.0,
respectively, which were lower than those in the NP group
(24917.0±2044.0, 4495.0±775.0, 14663.0±2320.0, 20988.0±2289.0,
P<0.01) (Fig. 3). We performed quantitative PCR to examine the
relative expression of the four channel genes. The relative expression
of TRPV1, Kir6.1, SUR2B and eNOS in the SP group was 0.559±0.609,
0.419±0.281, 0.166±0.087 and 0.383±0.110, respectively, which was
significantly lower than that in the NP group (1.098±0.341, 1.024±0.085,
1.243±0.335 and 1.219±0.247, P<0.01) (Fig. 4). Since gene
expression does not fully reflect protein expression, we performed
Western blotting to quantitatively examine whether this difference was
also present at the
protein
level. The relative quantitative analysis results (Fig. 5) showed that
the ratio of the gray value of each target protein to GAPDH in the SP
group was 0.282±0.058, 0.058±0.005, 0.132±0.007, 0.059±0.023,
respectively, which was lower than that in the NP group (0.688±0.145,
0.196±0.010, 0.514±0.018, 0.327±0.063, P<0.01), suggesting
that the relative protein expression of TRPV1, KATP subtype Kir6.1/SUR2B
and eNOS in the SP group was also significantly downregulated.
The roles ofeNOS
and Kir6.1/SUR2B channels in capsaicin/capsazepine-induced
relaxation in human umbilical vein endothelial cells
To explore the interaction of the four channels, we carried out further
cytological experiments. The relative gene expression of TRPV1, Kir6.1,
SUR2B and eNOS in the control group was 0.986±0.129, 1.439±0.358,
1.479±0.403 and 1.162±0.090, respectively; in the capsaicin group, it
was 4.568±0.810, 4.014±0.781, 5.505±0.287 and 2.821±0.377, respectively;
and in the capsazepine group, it was 0.077±0.010, 0.036±0.014,
0.046±0.010 and 0.083±0.005, respectively, and the differences were
statistically significant (P < 0.01) (Fig. 6). The Western
blot results showed that the relative protein expression of TRPV1,
Kir6.1, SUR2B and eNOS in the control group was 0.266±0.026,
0.226±0.014, 0.166±0.013 and 0.277±0.025, respectively; expression in
the capsaicin group was 0.763±0.044, 0.687±0.046, 0.493±0.035 and
0.498±0.022, respectively; and expression in the capsazepine group was
0.157±0.040, 0.057±0.005, 0.065±0.005 and 0.058±0.008, respectively
(P<0.01), and these differences were statistically significant
(P<0.01) (Fig. 7).