AIM: To investigate the roles of nuclear factor(NF)-κB and angiotensin Ⅱ receptor type 1(AT1R) in the pathogenesis of non-alcoholic fatty liver disease(NAFLD).METHODS: Forty-two healthy adult male SpragueDawley rats...AIM: To investigate the roles of nuclear factor(NF)-κB and angiotensin Ⅱ receptor type 1(AT1R) in the pathogenesis of non-alcoholic fatty liver disease(NAFLD).METHODS: Forty-two healthy adult male SpragueDawley rats were randomly divided into three groups:the control group(normal diet), the model group,and the intervention group(10 wk of a high-fat diet feeding, followed by an intraperitoneal injection of PDTC); 6 rats in each group were sacrificed at 6, 10,and 14 wk. After sacrifice, liver tissue was taken,paraffin sections of liver tissue specimens were prepared, hematoxylin and eosin(HE) staining was performed, and pathological changes in liver tissue(i.e., liver fibrosis) were observed by light microscopy.NF-κB expression in liver tissue was detected by immunohistochemistry, and the expression of AT1 R in the liver tissue was detected by reverse transcriptionpolymerase chain reaction(RT-PCR). The data are expressed as mean ± SD. A two-sample t test was used to compare the control group and the model group at different time points, paired t tests were used to compare the differences between the intervention group and the model group, and analysis of variance was used to compare the model group with the control group. Homogeneity of variance was analyzed with single factor analysis of variance. H variance analysis was used to compare the variance. P < 0.05 wasconsidered statistically significant.RESULTS: The NAFLD model was successful after 6wk and 10 wk. Liver fibrosis was found in four rats in the model group, but in only one rat in the intervention group at 14 wk. Liver steatosis, inflammation, and fibrosis were gradually increased throughout the model. In the intervention group, the body mass,rat liver index, serum lipid, and transaminase levels were not increased compared to the model group.In the model group, the degree of liver steatosis was increased at 6, 10, and 14 wk, and was significantly higher than in the control group(P < 0.01). In the model group, different degrees of liver cell necrosis were visible and small leaves, punctated inflammation,focal necrosis, and obvious ballooning degeneration were observed. Partial necrosis and confluent necrosis were observed. In the model group, liver inflammatory activity scores at 6, 10, and 14 wk were higher than in the control group(P < 0.01). Active inflammation in liver tissue in the intervention group was lower than in the model group(P < 0.05). HE staining showed liver fibrosis only at 14 wk in 4/6 rats in the model group and in 1/6 rats in the intervention group. NF-κB positive cells were stained yellow or ensemble yellow,and NF-κB was localized in the cytoplasm and/or nucleus. The model group showed NF-κB activation at6, 10, and 14 wk in liver cells; at the same time points,there were statistically significant differences in the control group(P < 0.01). Over time, NF-κB expression increased; this was statistically lower(P < 0.05) at14 weeks in the intervention group compared to the model group, but significantly increased(P < 0.05)compared with the control group; RT-PCR showed that AT1 R mRNA expression increased gradually in the model group; at 14 wk, the expression was significantly different compared with expression at 10 weeks as well as at 6 weeks(P < 0.05). In the model group, AT1 R mRNA expression was significantly higher than at the same time point in the control group(P <0.01).CONCLUSION: With increasing severity of NAFLD,NF-κB activity is enhanced, and the inhibition of NF-κB activity may reduce AT1 R mRNA expression in NAFLD.展开更多
Background The most significant biological change in intervertebral disc degeneration is the decrease of chondrocyte specific gene and protein expression of Sox9 and collagen type Ⅱ. Interleukin-1 （IL-1） is not exp...Background The most significant biological change in intervertebral disc degeneration is the decrease of chondrocyte specific gene and protein expression of Sox9 and collagen type Ⅱ. Interleukin-1 （IL-1） is not expressed in the normal intervertebral disc tissue but increases in the degenerated intervertebral disc tissue. This suggests that IL-1 may play a role in regulation of the expression of Sox9 and collagen type Ⅱ. Methods Human intervertebral disc cells were isolated and cultured. Sox9 and collagen type Ⅱ expression during treatment with IL-1, with or without the nuclear factor-κB （NF-κB） activity inhibitor curcumin, were detected by using reverse transcription-polymerase chain reaction （RT-PCR） and Western blotting, and the activity of the NF-κB signaling pathway was detected by the electrophoretic mobility shift assay （EMSA）. Results IL-1 lowered the mRNA level and protein expression of Sox9 and collagen type Ⅱ in the cultured intervertebral disc cells in a dose dependent manner （P 〈0.05）, and this effect was attenuated by curcumin. Curcumin alone had no effect on Sox9 and collagen type Ⅱ expression （P 〉0.05）. IL-1 at concentrations of 0.1 ng/ml, 1 ng/ml and 10 ng/ml could stimulate the activity of NF-κB in the intervertebral disc cells in a dose dependent manner （P 〈0.05） that was inhibited by curcumin. Conclusions We demonstrated the previously unknown function of IL-1 in inhibiting Sox9 and collagen type Ⅱ via NF-κB in the intervertebral disc cells. This inhibition can be attenuated by curcumin, which is an effective NF-κB activity inhibitor.展开更多
Background Low back pain has emerged as a widespread disease often caused by intervertebral disc degeneration.This study aimed to establish an in vitro cell culture model of rhesus monkey lumbar intervertebral discs a...Background Low back pain has emerged as a widespread disease often caused by intervertebral disc degeneration.This study aimed to establish an in vitro cell culture model of rhesus monkey lumbar intervertebral discs and to investigate the effect of combined connective tissue growth factor （CTGF） and tissue inhibitor of metalloprotease-1（TIMP-1） expression mediated by adeno-associated virus （AAV） on collagen type Ⅱ and proteoglycan levels.The purpose of these investigations was to explore potential methods for relieving the degeneration of lumbar intervertebral disc cells.Methods Rhesus monkey lumbar intervertebral disc nucleus pulposus cells （NPCs） were isolated by enzyme digestion,cultured, and transduced with rAAV2-CTGF-IRES-TIMP-1, rAAV2-CTGF, or rAAV2-TIMP-1 at a multiplicity of infection （MOl） of 106.The expression of collagen type Ⅱ and proteoglycan was measured using RT-PCR and Western blotting.The synthetic rate of proteoglycan was measured using 35S incorporation.Results Rhesus monkey lumbar intervertebral disc NPCs were transduced with rAAV2-CTGF-IRES-TIMP-1,rAAV2-CTGF, and rAAV2-TIMP-1 and the transduced genes were expressed and detected.Compared to the control,CTGF promoted the synthesis of collagen type Ⅱ and proteoglycan.TIMP-1 showed an enhancing effect on the expression of proteoglycan but no effect on collagen type Ⅱ.Expression of both genes in rhesus monkey lumbar intervertebral disc NPCs significantly enhances the synthesis of proteoglycan and collagen type Ⅱ.Conclusions Single gene transduction of CTGF or TIMP-1 can enhanced synthesis of proteoglycan.CTGF expression can also enhance collagen type Ⅱ protein synthesis.Combined transduction of both CTGF and TIMP1 can significantly promote the expression of proteoglycan and collagen type Ⅱ to levels greater than transduction of a single gene alone.Our study provides a good basis for multi-gene therapy to treat lumbar intervertebral disc degeneration.展开更多
基金Supported by grants from the Science and Technology Department of Sichuan Province,No.2011SZ0094
文摘AIM: To investigate the roles of nuclear factor(NF)-κB and angiotensin Ⅱ receptor type 1(AT1R) in the pathogenesis of non-alcoholic fatty liver disease(NAFLD).METHODS: Forty-two healthy adult male SpragueDawley rats were randomly divided into three groups:the control group(normal diet), the model group,and the intervention group(10 wk of a high-fat diet feeding, followed by an intraperitoneal injection of PDTC); 6 rats in each group were sacrificed at 6, 10,and 14 wk. After sacrifice, liver tissue was taken,paraffin sections of liver tissue specimens were prepared, hematoxylin and eosin(HE) staining was performed, and pathological changes in liver tissue(i.e., liver fibrosis) were observed by light microscopy.NF-κB expression in liver tissue was detected by immunohistochemistry, and the expression of AT1 R in the liver tissue was detected by reverse transcriptionpolymerase chain reaction(RT-PCR). The data are expressed as mean ± SD. A two-sample t test was used to compare the control group and the model group at different time points, paired t tests were used to compare the differences between the intervention group and the model group, and analysis of variance was used to compare the model group with the control group. Homogeneity of variance was analyzed with single factor analysis of variance. H variance analysis was used to compare the variance. P < 0.05 wasconsidered statistically significant.RESULTS: The NAFLD model was successful after 6wk and 10 wk. Liver fibrosis was found in four rats in the model group, but in only one rat in the intervention group at 14 wk. Liver steatosis, inflammation, and fibrosis were gradually increased throughout the model. In the intervention group, the body mass,rat liver index, serum lipid, and transaminase levels were not increased compared to the model group.In the model group, the degree of liver steatosis was increased at 6, 10, and 14 wk, and was significantly higher than in the control group(P < 0.01). In the model group, different degrees of liver cell necrosis were visible and small leaves, punctated inflammation,focal necrosis, and obvious ballooning degeneration were observed. Partial necrosis and confluent necrosis were observed. In the model group, liver inflammatory activity scores at 6, 10, and 14 wk were higher than in the control group(P < 0.01). Active inflammation in liver tissue in the intervention group was lower than in the model group(P < 0.05). HE staining showed liver fibrosis only at 14 wk in 4/6 rats in the model group and in 1/6 rats in the intervention group. NF-κB positive cells were stained yellow or ensemble yellow,and NF-κB was localized in the cytoplasm and/or nucleus. The model group showed NF-κB activation at6, 10, and 14 wk in liver cells; at the same time points,there were statistically significant differences in the control group(P < 0.01). Over time, NF-κB expression increased; this was statistically lower(P < 0.05) at14 weeks in the intervention group compared to the model group, but significantly increased(P < 0.05)compared with the control group; RT-PCR showed that AT1 R mRNA expression increased gradually in the model group; at 14 wk, the expression was significantly different compared with expression at 10 weeks as well as at 6 weeks(P < 0.05). In the model group, AT1 R mRNA expression was significantly higher than at the same time point in the control group(P <0.01).CONCLUSION: With increasing severity of NAFLD,NF-κB activity is enhanced, and the inhibition of NF-κB activity may reduce AT1 R mRNA expression in NAFLD.
基金The study was supported by a grant from the National Natural Science Foundation of China （No. 2004NSFC30471741）.
文摘Background The most significant biological change in intervertebral disc degeneration is the decrease of chondrocyte specific gene and protein expression of Sox9 and collagen type Ⅱ. Interleukin-1 （IL-1） is not expressed in the normal intervertebral disc tissue but increases in the degenerated intervertebral disc tissue. This suggests that IL-1 may play a role in regulation of the expression of Sox9 and collagen type Ⅱ. Methods Human intervertebral disc cells were isolated and cultured. Sox9 and collagen type Ⅱ expression during treatment with IL-1, with or without the nuclear factor-κB （NF-κB） activity inhibitor curcumin, were detected by using reverse transcription-polymerase chain reaction （RT-PCR） and Western blotting, and the activity of the NF-κB signaling pathway was detected by the electrophoretic mobility shift assay （EMSA）. Results IL-1 lowered the mRNA level and protein expression of Sox9 and collagen type Ⅱ in the cultured intervertebral disc cells in a dose dependent manner （P 〈0.05）, and this effect was attenuated by curcumin. Curcumin alone had no effect on Sox9 and collagen type Ⅱ expression （P 〉0.05）. IL-1 at concentrations of 0.1 ng/ml, 1 ng/ml and 10 ng/ml could stimulate the activity of NF-κB in the intervertebral disc cells in a dose dependent manner （P 〈0.05） that was inhibited by curcumin. Conclusions We demonstrated the previously unknown function of IL-1 in inhibiting Sox9 and collagen type Ⅱ via NF-κB in the intervertebral disc cells. This inhibition can be attenuated by curcumin, which is an effective NF-κB activity inhibitor.
基金This study was supported by a grant from the National Natural Science Foundation of China （No. 30471750）.
文摘Background Low back pain has emerged as a widespread disease often caused by intervertebral disc degeneration.This study aimed to establish an in vitro cell culture model of rhesus monkey lumbar intervertebral discs and to investigate the effect of combined connective tissue growth factor （CTGF） and tissue inhibitor of metalloprotease-1（TIMP-1） expression mediated by adeno-associated virus （AAV） on collagen type Ⅱ and proteoglycan levels.The purpose of these investigations was to explore potential methods for relieving the degeneration of lumbar intervertebral disc cells.Methods Rhesus monkey lumbar intervertebral disc nucleus pulposus cells （NPCs） were isolated by enzyme digestion,cultured, and transduced with rAAV2-CTGF-IRES-TIMP-1, rAAV2-CTGF, or rAAV2-TIMP-1 at a multiplicity of infection （MOl） of 106.The expression of collagen type Ⅱ and proteoglycan was measured using RT-PCR and Western blotting.The synthetic rate of proteoglycan was measured using 35S incorporation.Results Rhesus monkey lumbar intervertebral disc NPCs were transduced with rAAV2-CTGF-IRES-TIMP-1,rAAV2-CTGF, and rAAV2-TIMP-1 and the transduced genes were expressed and detected.Compared to the control,CTGF promoted the synthesis of collagen type Ⅱ and proteoglycan.TIMP-1 showed an enhancing effect on the expression of proteoglycan but no effect on collagen type Ⅱ.Expression of both genes in rhesus monkey lumbar intervertebral disc NPCs significantly enhances the synthesis of proteoglycan and collagen type Ⅱ.Conclusions Single gene transduction of CTGF or TIMP-1 can enhanced synthesis of proteoglycan.CTGF expression can also enhance collagen type Ⅱ protein synthesis.Combined transduction of both CTGF and TIMP1 can significantly promote the expression of proteoglycan and collagen type Ⅱ to levels greater than transduction of a single gene alone.Our study provides a good basis for multi-gene therapy to treat lumbar intervertebral disc degeneration.
