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Rapamycin ameliorates CCl4-induced liver fibrosis in mice through reciprocal regulation of the Th17/Treg cell balance.

Gu L, Deng WS, Sun XF, Zhou H, Xu Q - Mol Med Rep (2016)

Bottom Line: It was found that rapamycin treatment led to a significant reduction in the number of Th17 cells and in the expression levels of ROR‑γt in the liver tissues.Consequently, rapamycin treatment prevented the development of CCl4-induced hepatic fibrosis, which was shown by its histological appearances.These results suggested that the immunosuppressive effect of rapamycin on liver fibrosis was associated with the suppression of hepatic fibrogenesis and regulation of the Th17/Treg cell balance.

View Article: PubMed Central - PubMed

Affiliation: Department of Gastrointestinal Surgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200127, P.R. China.

ABSTRACT
Previous investigations have suggested that the activation of Th17 cells and/or deficiency of regulatory T cells (Tregs) are involved in the pathogenesis of liver fibrosis. The aim of the present study was to investigate the effect of rapamycin on immune responses in a carbon tetrachloride (CCl4)-induced murine liver fibrosis model. Liver fibrosis was induced by intraperitoneal administration with CCl4. Following injection of CCl4, the mice were treated intraperitoneally with rapamycin (1.25 mg/kg/day) for 8 weeks. Hematoxylin and eosin staining and Masson's trichrome staining were used for histological examination. The protein levels of forkhead/winged helix transcription factor P3, retinoic-acid-related orphan receptor (ROR)‑γt in liver tissue were determined by western blotting, the frequency of Th17 and Treg cells in the liver was evaluated by flow cytometry, and a suppression assay was measured by incorporating [3H]‑thymidine. In addition, to explore the effect of Tregs expanded with rapamycin on hepatic stellate cells (HSC), HSCs were co‑cultured with Tregs from rapamycin or phosphate‑buffered saline‑treated mice. It was found that rapamycin treatment led to a significant reduction in the number of Th17 cells and in the expression levels of ROR‑γt in the liver tissues. Simultaneously, the results of the present study showed a significant increase in the frequency of Tregs and a marked enhancement in the expression of forkhead/winged helix transcription factor P3 in the rapamycin‑treated mice. Furthermore, the Tregs in rapamycin‑treated mice had significantly higher suppressive effects, compared with the cells from mice treated with phospphate‑buffered saline. Consequently, rapamycin treatment prevented the development of CCl4-induced hepatic fibrosis, which was shown by its histological appearances. These results suggested that the immunosuppressive effect of rapamycin on liver fibrosis was associated with the suppression of hepatic fibrogenesis and regulation of the Th17/Treg cell balance.

No MeSH data available.


Related in: MedlinePlus

Rapamycin attenuates hepatic fibrosis induced by CCl4 in mice. (A) Pathological changes of liver fibrosis in each group were determined using H&E or Masson's trichrome staining (magnification, ×200). (B) Immunohistochemical analysis was used for detecting the protein expression of α-SMA and TGF-β1 in the liver tissues of each group. The results show the protein expression of TGF-β1 (magnification, ×200) and α-SMA (magnification, ×200) in the fibrotic livers of each group. CCl4, carbon tetrachloride; PBS, phosphate-buffered saline; H&E, hematoxylin and eosin; TGF-β1, transforming growth factor-β1; α-SMA, α-smooth muscle actin.
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f1-mmr-14-02-1153: Rapamycin attenuates hepatic fibrosis induced by CCl4 in mice. (A) Pathological changes of liver fibrosis in each group were determined using H&E or Masson's trichrome staining (magnification, ×200). (B) Immunohistochemical analysis was used for detecting the protein expression of α-SMA and TGF-β1 in the liver tissues of each group. The results show the protein expression of TGF-β1 (magnification, ×200) and α-SMA (magnification, ×200) in the fibrotic livers of each group. CCl4, carbon tetrachloride; PBS, phosphate-buffered saline; H&E, hematoxylin and eosin; TGF-β1, transforming growth factor-β1; α-SMA, α-smooth muscle actin.

Mentions: The liver fibrosis model was established by chronic CCl4 injection, and the degree of hepatic fibrosis was detected using H&E and Masson's trichrome staining (Fig. 1A). Following CCl4 administration, the liver tissues of the mice treated with PBS exhibited a distorted architecture, with extensive fibrosis combined with the development of micronodules throughout the liver parenchyma shown in the H&E staining. Liver injury was attenuated in the rapamycin-treated mice. The deposition of collagen fibers as an indicator of liver fibrosis was determined using Masson's trichrome staining. The pathological progression in liver fibrosis was attenuated by rapamycin, with fewer and smaller fibrotic nodules observed. As a marker of HSC activation, α-SMA is one of the sensitive indices of the rate of fibrogenesis (21). As shown in Fig. 1B, the expression of α-SMA was significantly elevated in the mice with CCl4-induced liver fibrosis, and was reduced following rapamycin administration. As a key factor of fibrogenesis, TGF-β in the rapamycin-treated mice showed reduced expression, compared with that in the PBS-treated mice.


Rapamycin ameliorates CCl4-induced liver fibrosis in mice through reciprocal regulation of the Th17/Treg cell balance.

Gu L, Deng WS, Sun XF, Zhou H, Xu Q - Mol Med Rep (2016)

Rapamycin attenuates hepatic fibrosis induced by CCl4 in mice. (A) Pathological changes of liver fibrosis in each group were determined using H&E or Masson's trichrome staining (magnification, ×200). (B) Immunohistochemical analysis was used for detecting the protein expression of α-SMA and TGF-β1 in the liver tissues of each group. The results show the protein expression of TGF-β1 (magnification, ×200) and α-SMA (magnification, ×200) in the fibrotic livers of each group. CCl4, carbon tetrachloride; PBS, phosphate-buffered saline; H&E, hematoxylin and eosin; TGF-β1, transforming growth factor-β1; α-SMA, α-smooth muscle actin.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4940054&req=5

f1-mmr-14-02-1153: Rapamycin attenuates hepatic fibrosis induced by CCl4 in mice. (A) Pathological changes of liver fibrosis in each group were determined using H&E or Masson's trichrome staining (magnification, ×200). (B) Immunohistochemical analysis was used for detecting the protein expression of α-SMA and TGF-β1 in the liver tissues of each group. The results show the protein expression of TGF-β1 (magnification, ×200) and α-SMA (magnification, ×200) in the fibrotic livers of each group. CCl4, carbon tetrachloride; PBS, phosphate-buffered saline; H&E, hematoxylin and eosin; TGF-β1, transforming growth factor-β1; α-SMA, α-smooth muscle actin.
Mentions: The liver fibrosis model was established by chronic CCl4 injection, and the degree of hepatic fibrosis was detected using H&E and Masson's trichrome staining (Fig. 1A). Following CCl4 administration, the liver tissues of the mice treated with PBS exhibited a distorted architecture, with extensive fibrosis combined with the development of micronodules throughout the liver parenchyma shown in the H&E staining. Liver injury was attenuated in the rapamycin-treated mice. The deposition of collagen fibers as an indicator of liver fibrosis was determined using Masson's trichrome staining. The pathological progression in liver fibrosis was attenuated by rapamycin, with fewer and smaller fibrotic nodules observed. As a marker of HSC activation, α-SMA is one of the sensitive indices of the rate of fibrogenesis (21). As shown in Fig. 1B, the expression of α-SMA was significantly elevated in the mice with CCl4-induced liver fibrosis, and was reduced following rapamycin administration. As a key factor of fibrogenesis, TGF-β in the rapamycin-treated mice showed reduced expression, compared with that in the PBS-treated mice.

Bottom Line: It was found that rapamycin treatment led to a significant reduction in the number of Th17 cells and in the expression levels of ROR‑γt in the liver tissues.Consequently, rapamycin treatment prevented the development of CCl4-induced hepatic fibrosis, which was shown by its histological appearances.These results suggested that the immunosuppressive effect of rapamycin on liver fibrosis was associated with the suppression of hepatic fibrogenesis and regulation of the Th17/Treg cell balance.

View Article: PubMed Central - PubMed

Affiliation: Department of Gastrointestinal Surgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200127, P.R. China.

ABSTRACT
Previous investigations have suggested that the activation of Th17 cells and/or deficiency of regulatory T cells (Tregs) are involved in the pathogenesis of liver fibrosis. The aim of the present study was to investigate the effect of rapamycin on immune responses in a carbon tetrachloride (CCl4)-induced murine liver fibrosis model. Liver fibrosis was induced by intraperitoneal administration with CCl4. Following injection of CCl4, the mice were treated intraperitoneally with rapamycin (1.25 mg/kg/day) for 8 weeks. Hematoxylin and eosin staining and Masson's trichrome staining were used for histological examination. The protein levels of forkhead/winged helix transcription factor P3, retinoic-acid-related orphan receptor (ROR)‑γt in liver tissue were determined by western blotting, the frequency of Th17 and Treg cells in the liver was evaluated by flow cytometry, and a suppression assay was measured by incorporating [3H]‑thymidine. In addition, to explore the effect of Tregs expanded with rapamycin on hepatic stellate cells (HSC), HSCs were co‑cultured with Tregs from rapamycin or phosphate‑buffered saline‑treated mice. It was found that rapamycin treatment led to a significant reduction in the number of Th17 cells and in the expression levels of ROR‑γt in the liver tissues. Simultaneously, the results of the present study showed a significant increase in the frequency of Tregs and a marked enhancement in the expression of forkhead/winged helix transcription factor P3 in the rapamycin‑treated mice. Furthermore, the Tregs in rapamycin‑treated mice had significantly higher suppressive effects, compared with the cells from mice treated with phospphate‑buffered saline. Consequently, rapamycin treatment prevented the development of CCl4-induced hepatic fibrosis, which was shown by its histological appearances. These results suggested that the immunosuppressive effect of rapamycin on liver fibrosis was associated with the suppression of hepatic fibrogenesis and regulation of the Th17/Treg cell balance.

No MeSH data available.


Related in: MedlinePlus