Abstract: Objective To investigate the role of RhoA/ROCK signaling transduction pathway
on high-glucose-induced proliferation of hepatic stellate cell (HSC) and synthesis of collagen
in rats. Methods HSC-T6 cells of SD rats were cultured in 1640 medium for 24 h and divided
into control group (5.5 mmol/L D-glucose), high-glucose group (25 mmol/L D-glucose), high
osmotic pressure group (5.5 mmol/L D-glucose + 19.5 mmol/L mannose) and high-glucose +
fasudil group (12.5 μmol/L, 25 μmol/L, 50 μmol/L). Proliferation of HSC was measured
by MTS assay. Level of hydroxyproline (Hyp) in the cell supernatant was determined by
Hyp kit. The expression of type Ⅰ and Ⅲ procollagen mRNA were determined by realtime ?uorescence quantitative polymerase chain reaction. Western blot was used to evaluate
the phosphorylation of myosin phosphatase target subunit 1 (MYPT1), extracellular signalregulated kinase (ERK), c-Jun N-terminal kinases (JNK) and p38mitogen-activated protein
kinase (p38MAPK). Results Compared with control group, phosphorylation level of MYPT1
(0.270 ± 0.007 vs 0.090 ± 0.008, P < 0.001), ERK (0.851 ± 0.027 vs 0.175 ± 0.038, P < 0.001),
JNK (0.869 ± 0.037 vs 0.488 ± 0.022, P < 0.001) and p38MAPK (0.498 ± 0.020 vs 0.144 ± 0.011,
P < 0.001) in high-glucose group increased signifcantly, proliferation of HSC (A value) (2.372 ±
0.098 vs 1.588 ± 0.087, P < 0.001) and Hyp level (27.924 ± 1.069 vs 17.643 ± 0.112, P <
0.001) increased significantly and expression of type Ⅰ(2.783 ± 0.167 vs 1.004 ± 0.008,
P < 0.001) and type Ⅲ (4.958 ± 0.143 vs 1.098 ± 0.014, P < 0.001) procollagen mRNA
upregulated significantly. Compared with high-glucose group, phosphorylation level of
MYPT1 (0.110 ± 0.007, P < 0.001; 0.101 ± 0.006, P < 0.001), ERK (0.473 ± 0.025, P <
0.001; 0.223 ± 0.031, P < 0.001), JNK (0.688 ± 0.024, P = 0.019; 0.576 ± 0.035, P < 0.001)
and p38MAPK (0.350 ± 0.021, P = 0.012; 0.305 ± 0.015, P = 0.019) in high-glucose + fasudil
group (25 μmol/L, 50 μmol/L) decreased signifcantly, proliferation of HSC (A value) (1.819 ±
0.104, P < 0.001; 1.613 ± 0.103, P < 0.001) and Hyp level (21.430 ± 0.714, P < 0.001;
18.574 ± 0.825, P < 0.001) decreased signifcantly and expression of type Ⅰ(1.580 ± 0.154,
P < 0.001; 1.167 ± 0.157, P < 0.001) and type Ⅲ (3.166 ± 0.073, P < 0.001; 2.524 ± 0.085,
P < 0.001) procollagen mRNA downregulated signifcantly. Phosphorylation level of MYPT1
ERK, JNK and p38MAPK and level of Hcy in high-glucose + fasudil group (12.5 μmol/L)
were signifcantly higher than those in high-glucose + fasudil 25 μmol/L group (all P < 0.001),
the above indexes in high-glucose + fasudil 25 μmol/L group were signifcantly higher than
those in high-glucose + fasudil 50 μmol/L group (all P < 0.001). Conclusions The RhoA/
ROCK signaling transduction pathway may mediate the high glucose-induced hepatic HSC
proliferation and collagen synthesis through the activation of downstream MAPKs, and
ROCK may be a novel target for the prevention of liver fbrosis in diabetes.
|