Effect of intravenous injecting plasmid encoding interleukin-19-IgG on experimental autoimmune myocarditis in rats

AIM: To evaluate the effect of intravenous injecting plasmid encoding interleukin-19-IgG on experimental autoimmune myocarditis (EAM) in rats.METHODS: Cardiac myosin was emulsified with equal volume of complete Freund's adjuvant. The animal model of EAM was established by injecting with the preparation in both footpads of the Lewis rats. The rats were intravenously injected with the plasmid encoding IL-19-IgG on day 6. Echocardiography was performed before the rats were sacrificed on day 17. The effect of IL-19-IgG plasmid injection was evaluated by measuring the heart weight/body weight, myocarditis area, relative expression levels of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in the hearts. The mRNA expression levels of related cytokines including IL-18, IL-1β, IL-12p35 and IFN-γ were detected.RESULTS: The rats in model group showed significant myocardial damage and a decrease in the left ventricular functions. The rats in the treatment group injected with IL-19-IgG plasmid showed an improvement of the cardiac functions. The ratio of heart weight/body weight, the area of myocarditis and the mRNA levels of ANP and BNP were significantly lower in IL-19-IgG treatment group than those in model group. The mRNA levels of IL-18, IL-1β, IL-12p35 and IFN-γ were also significantly decreased in IL-19-IgG treatment group.CONCLUSION: Intravenous injection of plasmid encoding IL-19-IgG effectively prevents the development of the left ventricular remodeling and myocardial damage in EAM rats.     

Atorvastatin inhibits IL-1β and IL-18 releases via lowering the expression of NLRP1 inflammasome

AIM: To explore the role of nucleotide-binding oligomerization domain-like receptor protein 1 (NLRP1) inflammasome in atorvastatin-induced reduction of interleukin-1β (IL-1β) and interleukin-18 (IL-18) releases from the THP-1 macrophages. METHODS: Lipopolysaccharide (LPS, 10 μg/L) was used to trigger the secretion of IL-1β and IL-18 in the THP-1 macrophages. The cells were incubated with different concentrations of atorvastatin (1, 10 and 20 μmol/L) for 24 h, or treated with 10 μmol/L atorvastatin for different time (12 h, 24 h and 48 h). NLRP1 siRNA was transfected into the THP-1 cells. The mRNA expression of NLRP1 inflammasome was detected by RT-PCR. The protein expression of NLRP1 inflammasome was determined by Western blot. The secretion of proinflammatory cytokines IL-1β and IL-18 was quantified by ELISA. RESULTS: Atorvastatin inhibited the mRNA and protein expression of NLRP1 inflammasome in the THP-1 macrophages in a dose- and time-dependent manner. Transfection of NLRP1 siRNA significantly decreased the protein expression of NLRP1 and promoted the suppressive effect of atorvastatin on IL-1β and IL-18 secretion in the THP-1 macrophages. CONCLUSION: Atorvastatin inhibits the production of IL-1β and IL-18 in the macrophages through decreasing NLRP1 inflammasome expression, possibly contributing to the anti-inflammatory effect of atorvastatin on atherosclerosis.     

Effect of IL-13 on expression of IL-1β in acute renal ischemia/ reperfusion injury in rats

AIM:To investigate the effects of IL-13 on expression of IL-1β in acute renal ischemia/reperfusion injury.METHODS:Fifty-seven male Wistar rats were randomly divided into 8 group: normal group, sham operation group, ischemia group, ischemia/reperfusion injury group(I/R), normal saline(NS)-treated group 1(C-1), NS-treated group 2(C-2), IL-13-treated group1(T-1)and IL-13-treated group 2(T-2).Rats were subjected to 45 min bilateral renal ischemia followed by reperfusion. rmIL-13 (1.5 μg/50 g body weight )was injected into the renal arteries through the abdominal aorta before ischemia(T-1) or immediately afterischemia(T-2).The serum level of IL-1β and the renal expression of IL-1β were determined in each group at 24 h post-ischemia. In addition, BUN, Cr and renal histology were also measured.RESULTS:(1)The serum level of IL-1β, gene expression and protein production of IL-1β in kidney decreased markedly in IL-13-treated groups.(2)Renal function and histology were significantly improved in IL-13-treated groups, renal injury scores decreased significantly.(3)A positive correlation were found between the serum level of IL-1β and BUN, SCr(r=0.708, P＜0.01;r=0.770, P＜0.01).CONCLUSION:These data suggest that IL-13 inhibit the expression of IL-1βand improve func-tion and histology of kidney in acute renal ischemia/reperfusion injury.     

Effect of IL-10 on IL-1β-induced cyclooxygenase-2 expression and prostaglandin E2 release in human mesangial cells

AIM: To investigate the effect of IL-10 on IL-1β-induced prostaglandin E₂(PGE₂) release and cyclooxygenase-2(COX-2) expression in human mesangial cells and to examine whether IL-10 has effect on the biological function of IL-1β.METHODS: The PGE₂ concentration in supernatants of HMC was measured by radioimmunoassay. The COX-2 mRNA and protein were measured by RT-PCR and Western blot, respectively. RESULTS: PGE₂ and COX-2 were significantly increased after treatment with IL-1β(P＜0.01 for both) in cultured human mesangial cells. IL-10 had no effects on basical production of COX-2 and PGE₂(P＞0.05, respectively), while it inhibited IL-1β-elicited PGE₂ production, as well as COX-2 mRNA and protein expression in a concentration-dependent fashion. CONCLUSIONS: These results indicated that IL-10 depressed the IL-1β-induced release of PGE₂ and expression of COX-2. These data suggested that IL-10 could exert anti-inflammatory actions at several levels, not only by inhibiting the production of pro-inflammatory cytokines but also by suppressing their biological function.     

Effect of recombinant rat CC16 protein on LPS-induced expression of TNF-α, IL-6 and IL-8 in rat tracheal epithelial cells

AIM: To explore the effect of recombinamt rat CC16 protein (rCC16) on LPS-induced expression of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and IL-8 in the rat tracheal epithelial (RTE) cells.METHODS: The RTE cells were incubated with rCC16 at concentrations of 0.5, 1.0 and 2.0 mg/L in serum-free media for 2 h prior to LPS (0.1 mg/L) treatment for further 24 h. The cells were harvested for assessing the mRNA levels of TNF-α, IL-6 and IL-8 by RT-qPCR. The cell culture supernatants were collected for analyzing the protein levels of TNF-α, IL-6 and IL-8 by ELISA. In addition, the nuclear translocation of nuclear factor-κB (NF-κB) p65 was tested by Western blot.RESULTS: rCC16 inhibited LPS-induced IL-6 and IL-8 expression at both mRNA and protein levels in the RTE cells in a concentration-dependent (0~2 mg/L) manner, as demonstrated by RT-qPCR and ELISA. However, no concentration-dependent manner between the dose of rCC16 and TNF-α expression was observed, and rCC16 inhibited LPS-induced TNF-α expression at lower concentration (0.5 mg/L). rCC16 concentration-dependently inhibited the effects of LPS on the level of nuclear translocation of NF-κB p65.CONCLUSION: rCC16 suppresses LPS-mediated TNF-α, IL-6 and IL-8 production through inactivation of NF-κB activity in RTE cells.[KEY WORDS] CC16 protein; Airway inflammation; LPS; Inflammatory mediators; Nuclear factor-κB     

Effect of ischemic post-conditioning on Egr-1 and IL-1β expression in ischemia-reperfusion injured lung in rats

AIM: To investigate the protective effects of ischemic post-conditioning on the expression of early growth response factor 1 (Egr-1) and interleukin-1β(IL-1β) in ischemia-reperfusion injured lung in rats. METHODS: The model of lung ischemia-reperfusion injury was established in 24 rats and the rats were randomly allocated to 3 different groups (n=8 in each group): (1) sham group: only sham operation (thoracotomy) and no ischemia for 3 h; (2)ischemia-reperfusion group (I/R group): interruption of pulmonary perfusion and ventilation for 1 h followed by reperfusion for 2 h; (3) ischemic post-conditioning group (IPostC group): ischemic post-conditioning (5 min of reperfusion and 5 min of ischemia for 3 times) between the end of ischemia and the beginning of the reperfusion followed by reperfusion for 1.5 h. The lung tissues (prepared to small pieces of about 20 mg) were collected and homogenized at the end of the experiment. The concentration of myeloperoxidase (MPO) in the homogenate was determined. The wet to dry weight ratio (W/D) of the lung tissues was also measured at the end of reperfusion. The pathological changes of the lung tissues were observed under light microscope after reperfusion. The mRNA expression of Egr-1 and IL-1β in the lung tissues was detected by RT-PCR. RESULTS: Compared with sham group, the mRNA expression of Egr-1 and IL-1β, the levels of MPO and W/D were significantly increased in I/R group (P<0.05). The inflammatory responses of the lungs in I/R group were significantly severer than those in sham group. Compared with I/R group, the mRNA expression of Egr-1 and IL-1β, the levels of MPO and W/D in IPostC group were significantly decreased (P<0.05). The inflammatory responses of the lungs in IPostC group were also significantly attenuated. CONCLUSION: Ischemic post-conditioning significantly reduces ischemic reperfusion injury of the lung by inhibiting the expression of Egr-1 and IL-1β.     

Effect of NOD8 on production of nitric oxide,IL-1β and TNF-α in LPS-treated macrophages

AIM: To investigate the effect of NOD8 on lipopolysaccharide (LPS)-induced releases of nitric oxide (NO), tumor necrosis factor α (TNF-α) and interleukin-1β (IL-1β) in RAW264.7 cells. METHODS: The plasmids of pEGFP-C2 and pEGFP-NOD8 were transfected into RAW264.7 cells respectively. The transfected and non-transfected cells were stimulated by LPS for 0, 6, 12 and 24 h. NO production was evaluated by Griess reagent assay, and the levels of IL-1β and TNF-α were measured by ELISA. The protein expression of NOD8 and the nuclear translocation of nuclear factor κB (NF-κB) p65 subunit were detected by Western blotting. The level of activated caspase-1 was determined by fluorimetric method. RESULTS: Compared with pEGFP-C2 group, the protein expression of NOD8 was significantly elevated in pEGFP-NOD8+LPS group. The releases of NO, IL-1β and TNF-α were obviously increased after RAW264.7 cells were treated with LPS for 6 h, 12 h and 24 h, and while the secretion of NO was significantly reduced in the cells transfected with pEGFP-NOD8 and induced by LPS for 12 h and 24 h, and the release of IL-1β was also significantly reduced at 6 h, 12 h and 24 h. However, no significant difference of TNF-α release was observed between pEGFP-C2+LPS group and pEGFP-NOD8+LPS group. The activation of caspase-1 in RAW264.7 cells stimulated with LPS for 6 h, 12 h and 24 h was markedly increased, and the expression of NF-κB p65 subunit in the cytoplasm was significantly decreased, indicating that p65 nuclear translocation was increased. In addition, the activation of caspase-1 and the nuclear translocation of p65 were significantly inhibited in pEGFP-NOD8+LPS group. CONCLUSION: NOD8 suppresses the releases of LPS-induced NO and IL-1β in RAW264.7 cells by inhibiting the activation of caspase-1 and NF-κB.     

Effect of Ganoderma lucidum spores on IL-1β and c-Fos in the brain tissue of epilepsy rats

AIM: To observe the influence of Ganoderma lucidum spores on the cytokine IL-1β and c-Fos in the brain tissue of epilepsy rats. METHODS: The IL-1β level was examined by radioimmunoassay and the c-Fos expression was measured by mmunohistochemical assay. RESULTS: Comparing the Ganoderma lucidum spores group with the epilepsy model group: c-Fos positive cell count in brain cortex and hippocampus in treatment group was obviously reduced. IL-1β level in brain tissue was also reduced obviously. CONCLUSION: Ganoderma lucidum spores effectively reduces cytokine IL-1β in brain tissue of epilepsy rats, improves the immunity dysfunction and plays a role in anti-epilepsy through suppressing c-Fos expression in epilepsy rats brain tissue and blocking of LRG.     

The effects of rhIL-1β on human fetal islets function and IL-6 production

AIM: To study rhIL-1β effects on fetal islet function and IL-6 production in vitro METHODS: Islets from fetal pancreas was separated by collagenase type V (0.5 mg/mL) and cultured in vitro The islets were exposed to culture medium alone for 48 h or with different concentration of rhIL-1β The supernatants of culture of human fetal islets were assayed for IL-6, insulin and glucagon RESULTS:(1) IL-6 activity was increased 4 0 folds (74-294 mU/islet) when islets were exposed to rhIL-1β(20U/mL); (2) IL-6 McAb significantly reduced IL-6 activity in islet supernatants from control group or islet exposed to rhIL-1β treated group; (3)IL-6 mRNA in human fetal islet exposed to rhIL-1β is higher than control in dot hybridization; (4) Soluble insulin and cellular insulin within islet released to supernatants was slightly decreased (0.48～0.78 IU/islet and 0.65～0.79 IU/islet); (5) Glucagon secretion was significantly increased 3.2 folds (1.0～3.2 pg/islet) CONCLUSION: Pancreatic islets produce IL-6 is up-regulated by rhIL-1β On the other hand, Il-6 produced by the islet may act as a costimulator for autoreactive B and T lymphocytes in autoimmune diabetes.     

Protective effect of recombinant SCR15-18 domain of human complement receptor type 1 on intestinal ischemia and reperfusion injury

AIM: To investigate the protective effect of recombinant SCR15-18 domain of human complement receptor type 1 (CR1-SCR-15-18) on intestinal ischemia and reperfusion in a rat model. METHODS: Sprague-Dawley rats were randomly divided into 3 groups: sham operation(SO) group, ischemia and reperfusion (I/R) group and CR1-SCR15-18 treatment group. The superior mesenteric artery of the rats was clamped for 30 min followed by 60 min of reperfusion. PBS alone or CR1-SCR15-18 protein (30 mg/kg) in PBS was intravenously administered 5 min before reperfusion. Intestinal vascular permeability, myeloperoxidase (MPO), malondialdehyde (MDA) and superoxide dismutase (SOD) were measured. The histopathological changes of intestinal mucosa were examined by HE staining and complement 3 was detected by immunohistochemical analysis. RESULTS: Compared with SO group, the vascular permeability, the activity of MPO and the content of MDA in I/R group were significantly increased, and the activity of SOD was decreased. HE staining demonstrated that I/R induced severe intestinal histological damages and the increased amount of complement 3 and its derivates were deposited in the necrosis area. Compared with I/R group, the vascular permeability, the activity of MPO and the content of MDA were decreased and the activity of SOD was significantly increased in CR1-SCR15-18 treatment group. CR1-SCR15-18 also significantly attenuated intestinal histological injury, and reduced the deposition of complement 3 and its derivates in the necrosis zone. CONCLUSION: sCR1-SCR15-18 protein exerts a protective effect against intestinal I/R injury in rats, possibly by inhibiting the activation of complement.     

Effect of ginsenoside Rb1 on liver cell pyroptosis in hyperlipidemia rats and its possible mechanism

AIM:To discuss the mechanism of ginsenoside Rb1 against liver lipid deposition by observing the effect of ginsenoside Rb1 on liver cell pyroptosis in hyperlipidemia rats. METHODS:Totally 32 healthy SPF rats were randomly divided into control group, model group, ginsenoside Rb1 group and simvastatin group. The rats in control group was given the basic feed, while the others were given high-fat diet. The rats in ginsenoside Rb1 group and simvastatin group were given corresponding drugs. The rats in control group and model group were intraperitoneal injected with equal volume of saline. Eight weeks later, the serum levels of triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) were tested by the automatic biochemistry analyzer. The pathological changes of the liver tissues were observed with HE staining. The protein and mRNA expression levels of pyroptosis-related factors NLRP3, caspase-1, IL-1β, IL-18 and GSDMD were detected by Western blot and RT-qPCR. RESULTS:Compared with control group, the serum levels of TC, TG and LDL-C in model group were increased significantly (P<0.01), and the HDL-C content was decreased significantly (P<0.05). The steatotic liver cells covered the visual field. The mRNA and protein expression levels of NLRP3, caspase-1, IL-1β, IL-18 and GSDMD were increased significantly (P<0.01). Ginsenoside Rb1 significantly decreased the serum levels of TC, TG and LDL-C (P<0.05), and significantly increased the content of HDL-C (P<0.01). Ginsenoside Rb1 also significantly decreased the degree of steatosis, and the number and size of lipid droplets. The mRNA and protein expression levels of NLRP3, caspase-1, IL-1β, IL-18 and GSDMD were decreased significantly (P<0.05 or P<0.01). CONCLUSION:Ginsenoside Rb1 atte-nuates liver injury and inhibits liver lipid deposition in hyperlipidemia rats by reducing the expression of hepatic pyroptosis-related factors.     

Effect of aminoguanidine on TNF-α,IL-1β and neuronal apoptosis after focal cerebral ischemic injury in rats

AIM: To evaluate the effect of aminoguanidine (AG) on inflammatory factors and neuronal apoptosis after focal cerebral ischemic injury in rats and the possible mechanism of protective effect of AG against cerebral ischemic injury.METHODS: Thirty male SD rats (weighing 250 g-280 g) were randomly divided into three groups: (1) sham operated group (SH group,n=10),(2) ischemic groups (IS group,n=10),(3) AG group (n=10).In AG group,AG at dose of 100 mg·kg-1 was given intraperitoneally twice a day for 3 consecutive days.In IS group,normal saline was given instead of AG.Focal cerebral ischemia was produced by middle cerebral artery occlusion (MCAO) for 12 h.A nylon thread with rounded tip was inserted into left internal carotid artery cranially until resistance was felt.The distance from bifurcation of common carotid artery to the tip of the thread was about 18-19 mm.Focal cerebral ischemia was confirmed by left Horners syndrome and right side hemiplegia.In SH group,the carotid artery was exposed but no thread was inserted.The expression of tumor necrosis factor-α(TNF-α) was determined by immunochemistry and the content of interleulin-1β(IL-1β) was measured by radioimmunoassay.The expressions of Bcl-2 and Bax protein were detected by flow cytometry.RESULTS: The expression of TNF-α and the content of IL-1β were markedly increased after MCAO.Significantly increased DNA fragmentation,the indication of apoptosis,was detected after MCAO.The expression of TNF-α and the content of IL-1β were significantly lower in AG group than those in IS group.The percentage of apoptosis cells and expression of Bax protein were markedly lower in AG group than those in IS group but still significantly higher than those in SH group.The expression of Bcl-2 protein was markedly higher in AG group than that in IS group.No significant difference in the expression of Bcl-2 protein between IS and SH group was observed.CONCLUSION: AG inhibits the increase in the expression of TNF-α and the content of IL-1β,and protects neurons from apoptosis induced by focal cerebral ischemia through increasing the Bcl-2 protein expression and inhibiting the Bax protein expression.     

Effect and mechanism of Qing-Kai-Ling on endotoxin-induced fever in rabbits

AIM:To explore the antipyretic mechanism of Qing Kai-Ling (QKL) injection on endotoxin (ET)-induced fever in rabbits.METHODS:Rabbit models of endotoxin (ET)-induced fever were duplicated. The rectal temperature was measured by digital thermograph. The cAMP and IL-1β content in the hypothalamus (HP), the cAMP content in the cerebrospinal fluid (CSF), and the arginine vasopressin (AVP) content in the ventral septal area (VSA) were determined by radioimmunoassay.RESULTS:① QKL had significant antipyretic effect on ET-induced fever(P<0.01), ② The production of IL-1β and cAMP in HP was significantly inhibited by QKL treatment (P<0.01), ③ QKL markedly decreased the cAMP content in the CSF and AVP content in the VSA(P<0.01).CONCLUSION:The antipyretic mechanisms of QKL are probably due to inhibiting the production of the endogenous pyrogen and central mediator of fever, and meanwhile stimulating the release of the antipyretic substances.     

Effect of Jiere Xingshen Injection on cAMP,IL-1β content in hypothalamus of ET febrile rabbits

AIM: The effects of Jiere Xingshen(JRXS) Injection on cAMP, IL-1_β content in hypothalamus (HP) of endotoxin(ET)-induced feverish rabbits were studied. METHODS: The ET-induced fever model was established in rabbits and the cAMP content in hypothalamus (HP) and csf, IL-1_β content in HP were determined by radioimmunoassay following intravenous infusion of JRXS. RESULTS: In ET group, the ΔT[(0.40±0.11)℃], TRI₁(1.78±0.79), cAMP content in HP[(2.90±0.40)nmol/g], cAMP content in csf[(0.40±0.11)nmol/L)], IL-1_β content in HP[(6.08±0.79)ng/g] were higher than that of NS and JRXS+ET group (P＜0.01). In JRXS+ET group, the ΔT[(0.10±0.10)℃], TRI₁(0.36±0.64), cAMP content in HP[(1.37±0.27)nmol/g], cAMP content in csf[(14.4±3.69)nmol/L)], IL-1_β content in HP[(2.90±0.37)ng/g] were very close to that of NS group but lower than that of the ET group (P＜0.01);The cAMP content in HP and csf, IL-1_β content in HP paralleled with the fluctuation of temperature. CONCLUTION: JRXS Injection has significant inhibitory effect on ET-induced fever by inhibiting cAMP and IL-1_β production in hypothalamus.     

Effects of taurine on the change of apoptosis induced by IL-1β, TNF-α and IFN-γ in rat pancreatic islet cells

AIM: To investigate the changes of apoptosis in isolated pancreatic islet cells, insulin secretion, expression of Bcl-xL and Bax induced by combination of IL-1β, TNF-α and IFN-γ, and effects of taurine on them.METHODS: Isolated pancreatic islet cells from Wistar rat were incubated in monolayer in vitro. NO^-₂/ NO^-₃ production, NOS activity, insulin secretion, the protein expression of Bcl-xL and Bax, percentage of islet cell apoptosis and DNA fragmentation in pancreatic islet cells incubated with combination of IL-1β, TNF-α and IFN-γ were measured, and the effects of taurine on the changes of them were further investigated. RESULTS: Combination of IL-1β, TNF-α and IFN-γ induced a significant increase in percentage of pancreatic islet cell apoptosis, NO^-₂/ NO^-₃ production and NOS activity, DNA ladder appearance, a decrease in insulin content, up-regulation in the protein expression of Bax and down-regulation in the protein expression of Bcl-xL (P<0.01), which were blocked by addition of taurine (P<0.01). These effects occurred in a dose dependent manner.CONCLUSION: Taurine attenuates β cell apoptosis induced by IL-1β, TNF-α and IFN-γ. The mechanism of which may be the inhibition of NOS activity and the decrease of NO production as well as the downregulation of Bax/Bcl-xL proportion.     

Cardiac hypertrophy induced by exercise training:the function of AT1 receptor,autophagy and miRNAs

As a mechanical and exogenous stimulus, exercise training induces cardiac physiological hypertrophy, and the cardiac structure is changed slowly, steadily and coordinately. Simultaneously, energy metabolism and function of the cardiac muscle are also improved. These are positive adaptations in the heart when experiencing endurance exercise training. Recently, angiotensin Ⅱ type 1 (AT1) receptor, autophagy and miRNAs are all considered as important regulators to cardiac hypertrophy induced by exercise training at different molecular levels. Fully understanding the relations and the important role of AT1 receptor, autophagy and miRNAs in cardiac physiological hypertrophy will further enrich the signaling pathway of cardiac hypertrophy induced by exercise training.     

Effect of angiotensin-(1-7) on angiotensin II-induced rat renal interstitial fibroblast activation

AIM: To explore the influence of angiotensin-(1-7) on angiotension II (Ang II)-induced activation and extracellular matrix secretion in rat renal interstitial fibroblasts (NRK-49F cells). METHODS: The NRK-49F cells were maintained and sub-cultured, then the cells were divided into control group, Ang II group, Ang-(1-7) group and Ang II+Ang-(1-7) group. The expression of α-smooth muscle actin(α-SMA),transforming growth factor β₁ (TGF-β₁) and insulin-like growth factor I(IGF-I) was detected by the method of immunocytochemistry when the cells were cultured for 72 h. The content of TGF-β₁, IGF-I and collagen type I(Col I) in the cultured supernatants were measured by ELISA. RESULTS: In control group and Ang-(1-7) group, only basic expression of α-SMA and almost no expression of TGF-β₁, IGF-I and Col I were observed. Compared with control group, the expression of α-SMA, TGF-β₁, IGF-I and Col I was increased in Ang II group. Compared with Ang II group, the expression of α-SMA, TGF-β₁, IGF-I and Col I was significantly decreased in Ang II+Ang-(1-7) group.CONCLUSION: Ang-(1-7) inhibits the activation of renal interstitial fibroblasts and decreases the Ang II induced secretion of Col I by suppressing TGF-β₁ and IGF-I expression.