硫化氢对肝纤维化大鼠肝脏Ⅰ、Ⅲ型胶原表达的影响

Protective effects of hydrogen sulfide on portal hypertensive vasculopathy in rabbits by activating AKT-NF-κB pathway

The role of hydrogen sulfide (H₂S) in portal hypertension (PH)-induced esophagus-gastric junction vascular lesions in rabbits was observed. The rabbit PH models were established. The animals were randomly divided into the following groups: normal, PH, PH+sodium hydrosulfide (PH+S), PH+propargylglycine (PH+PPG). The plasma H₂S levels, apoptosis of esophageal-gastric junction vascular smooth muscle cells, and the expression of nuclear transcription factor-κB (NF-κB), p-AKT, IκBa and Bcl-2 were detected. The cystathionine γ lyase (cystathionine-gamma-splitting enzyme, CSE) in the junction vascular tissue was measured. The results showed that the plasma H₂S levels and the CSE expression levels had statistically significant difference among different groups (P<0.05). As compared with PH group, plasma H₂S levels were declined obviously (11.9±4.2 vs. 20.6±4.5, P<0.05), and CSE expression levels in the junction vascular tissue were notably reduced (1.7±0.6 vs. 2.8±0.8, P<0.05), apoptosis rate of vascular smooth muscle cells per unit area was significantly decreased (0.10±0.15 vs. 0.24±0.07, P<0.05), and the expression levels of p-AKT and NF-κB were significantly decreased (2.31±0.33 vs. 3.04±0.38, P<0.05; 0.33±0.17 vs. 0.51±0.23, P<0.05), however, IκBa and Bcl-2 expression increased obviously (5.57±0.17 vs. 3.67±0.13, P<0.05; 0.79±0.29 vs. 0.44±0.36, P<0.05) in PH+PPG group. As compared with PH group, H₂S levels were notably increased (32.7±7.3 vs. 20.6±4.5, P<0.05), the CSE levels in the junction vascular tissue were significantly increased (6.3±0.7 vs. 2.8±0.8, P<0.05), apoptosis rate of vascular smooth muscle cells per unit area was significantly increased (0.35±0.14 vs. 0.24±0.07, P<0.05), and the expression levels of p-AKT and NF-κB were significantly increased (4.29±0.49 vs. 3.04±0.38, P<0.05; 0.77±0.27 vs. 0.51±0.23, P<0.05), yet IκBa and Bcl-2 expression decreased significantly (3.23±0.24 vs. 3.67±0.13, P<0.05; 0.31±0.23 vs. 0.48±0.34, P<0.05) in PH+S group. It is concluded that esophagus-gastric junction vascular lesions happen under PH, and apoptosis of smooth muscle cells is declined. H₂S can activate NF-κB by the p-AKT pathway, leading to the down-regulation of Bcl-2, eventually stimulating apoptosis of vascular smooth muscle cells, easing PH. H₂S/CSE system may play an important role in remission of PH via the AKT-NF-κB pathway.

Exogenous hydrogen sulfide promotes proliferation and inhibits apoptosis of hepatocytes via PI3K/Akt pathway

AIM: To explore the effect of exogenous hydrogen sulfide on rat hepatocyte proliferation and apoptosis and the role of phosphoinositide-3-kinase (PI3K)/Akt pathway.

METHODS: Female SD rats were subcutaneously injected with carbon tetrachloride to induce hepatic fibrosis, and hepatocytes were isolated from the rats. Primary hepatocytes were divided into three groups: a normal control group, a hydrogen sulfide group, and an LY294002 plus hydrogen sulfide group. MTT method was used to determine cell proliferation. Apoptosis of liver cells was detected by Hoechst 33342 staining. The expression of PI3K and phosphorylated Bad protein was detected by Western blot.

RESULTS: Sodium hydrosulfide at 50 μmol/L promoted cell proliferation (P < 0.05, compared with the control group), while 50 μmol/L LY294002 inhibited cell proliferation (P < 0.05, compared with the control group). Compared with the control group and sodium hydrosulfide group, the LY294002 plus hydrogen sulfide group had a significantly higher rate of cell apoptosis (P < 0.05). The expression of PI3K and phosphorylated Bad protein in the sodium hydrosulfide group was significantly higher than that in the control group and LY294002 plus hydrogen sulfide group (P < 0.05). However, PI3K and phospho-Bad protein expression in the LY294002 plus hydrogen sulfide group was significantly less than in the control group (P < 0.05).

CONCLUSION: Hydrogen sulfide promotes primary hepatocyte proliferation and inhibits its apoptosis possibly through the PI3K/Akt pathway.

Hydrogen sulfide delays process of experimental hepatic fibrosis in rats through PI3K/AKT/GSK-3β signal pathway

AIM: To investigate whether hydrogen sulfide (H₂S) delays the process of experimental hepatic fibrosis through the phosphoinositide-3-kinase (PI3K)/AKT/glycogen synthesis kinase-3β (GSK-3β) signal pathway.

METHODS: Sodium hydrogen sulphide (NaHS) was selected as the donor of H₂S and LY294002 as the specific blocker of PI3K/AKT signaling. Forty-eight female SD rats were divided randomly and equally into 6 groups: a normal group (N group), a liver fibrosis group (C group), a DMSO group (D group), an LY294002 intervention group (LY group), a NaHS intervention group (S group), and an LY294002 + NaHS intervention group (LS group). Liver fibrosis was induced in rats with carbon tetrachloride. The above agents were given by intraperitoneal injection, once a day for a total of 12 times. For the N group and C group, 0.9% sodium chloride injection (6 mL/kg of body mass) was intraperitoneally injected; for the D group, 2‰ DMSO (6 mL/kg of body mass) was given; for the LY group, LY294002 solution 0.3 mg/(kg•d) was given; for the S group, NaHS solution 56 μmol/(kg•d) was given; for the LS group, NaHS and LY294002 were given simultaneously. Fibrosis was staged using histopathological methods. The expression of GSK-3β was detected by Western blot.

RESULTS: Compared to the C group, the stage of fibrosis was downgraded (P < 0.01) and the expression of GSK-3β was decreased (P < 0.01) in the S group. Compared to the LS group, the expression of GSK-3β was increased in the LY group (P < 0.01) and was decreased in the S group (P < 0.01), and the stage of fibrosis in the S group was also downgraded (P < 0.01).

CONCLUSION: H₂S can decrease the expression of GSK-3β and delay the process of liver fibrosis in rats through the PI3K/AKT/GSK-3β signal pathway.