Relationship between peritubular capillary injury and renal interstitial fibrosis in mice with unilateral ureteral obstruction

AIM: To observe the injury of peritubular capillary (PTC), hypoxia and interstitial fibrosis after unilateral ureteral obstruction (UUO), and to explore the effects of PTC injury and hypoxia on interstitial fibrosis in mouse model of UUO. METHODS: Forty-eight male KM mice were randomly divided into control group and UUO group. On the 1st, 3rd, 7th and 14th days, 6 mice in each group were sacrificed. The changes of pathomorphism in the kidney were observed by HE and Masson staining. The expression levels of thrombospondin-1 (TSP-1), vascular endothelial growth factor (VEGF) and hypoxia-inducible factor-1α (HIF-1α), and PTC density were detected by immunohistochemistry. The protein expression of VEGF was also determined by Western blotting. RESULTS: No histological abnormalities of the kidneys were observed in sham-operated mice. The expression of TSP-1 was increased 1 day after UUO, and significantly increased on the 3rd, 7th and 14th days(P<0.05). The expression of VEGF was obviously decreased(P<0.05). PTC density was gradually decreased. The expression of HIF-1α was gradually increased, and renal interstitial area was gradually expanded. PTC density was negatively correlated with the expression of TSP-1 and HIF-1α (r=-0.874 and r=-0.930, respectively). VEGF expression was positively correlated with PTC density (r=0.745). PTC density was negatively correlated with the area of renal fibrosis (r=-0.787). HIF-1α expression was positively correlated with the area of renal fibrosis (r=0.835, P<0.05). CONCLUSION: In mouse UUO model, the expression of TSP-1 is increased. The expression of VEGF is reduced. The peritubular capillary injury and tissue hypoxia are aggravated, and renal interstitial fibrosis area is expanded. Ischemia and hypoxia may play an important role in the progression of UUO.     

p38MAPK expression and apoptosis in the rat unilateral ureteral obstruction model

AIM: To investigate the expression of p38 mitogen-activated protein kinase (p38MAPK) in the kidney after unilateral ureteral obstruction (UUO) in rats and the functional role of it on apoptosis and fibrosis.METHODS: Eighteen Wistar rats underwent UUO were killed at 3, 7, 14 days. Additional 7 rats were sham operated. Histological changes were observed by HE and Masson staining. Immunohistochemistry study was performed on renal tissue for proliferating cell nuclear antigen (PCNA). Apoptotic cells were determined by terminal deoxynucleotidyl transferase- mediated dUTP nick end labeling (TUNEL) and the electrophoresis analysis of genomic DNA. Western blotting of cysteinyl aspartate specific proteinase-3 (caspase-3), p38MAPK and p-p38MAPK were measured.RESULTS: UUO induced a significant increase in renal tubular and interstitial cell apoptosis, immunohistochemistry of PCNA and Western blotting of caspase-3, p-p38MAPK as well as severe morphology changes. However, there was no significant difference between UUO and the control in Western blotting of p38MAPK.CONCLUSION: An in vivo model of renal fibrosis after UUO demonstrates that activated or phosphorylated p38MAPK plays a role in apoptosis of renal tubulointerstitial cells.     

Increased fucosyltransferase 8 expression in rat kidney with unilateral ureteral obstruction

AIM: To investigate the effect of fucosyltransferase 8 (FUT8) on rat renal interstitial fibrosis induced by unilateral ureteral obstruction (UUO). METHODS: Ninety male Wistar rats were randomly divided into normal control group (control), sham operation group (sham) and UUO group, and sacrificed on day 1, 3, 7, 14 and 21 after operation. Serum creatinine and urea nitrogen were detected to assess renal function. PAS and Masson staining were used to observe histological changes of the rat kidneys. The time-correlated expression of FUT8 in the kidney was monitored by RT-PCR and Western blotting. The protein expression levels of FUT8 and activin receptor-like kinase 5(ALK5) were determined by immunofluorescence double-staining. Immunohistochemical staining was also used to assess the protein expression of fibronectin (FN), type I collagen (Col I) and α-smooth muscle actin (α-SMA). RESULTS: Compared with control group, serum creatinine and urea nitrogen in UUO group elevated on day 3 after operation (P<0.05) and reached the peak value on day 21 after operation (P<0.01). Renal tubule atrophy and renal interstitial fibrosis were observed in UUO group 7 and 14 days after operation. The mRNA and protein expression levels of FUT8 increased markedly in UUO group on day 3 (P<0.05) and reached its peak value on day 14 and 21 after operation (P<0.01). The results of immunofluorescence and immunohistochemistry showed that FUT8 and ALK5 were coexpressed in renal tubulointestitium. FN, Col I and α-SMA were significantly elevated in UUO group (P<0.05), and were positively correlated with the expression of FUT8 (P<0.05).CONCLUSION: The expression of FUT8 influences the progress of renal interstitial fibrosis, tubule atrophy and inflammatory cell infiltration in the kidney.     

Expression of Sonic hedgehog pathway-related genes in kidney tissues of rats with unilateral ureteral obstruction

AIM: To investigate the role of Sonic hedgehog (Shh) signaling pathway in renal interstitial fibrosis in the rats with unilateral ureteral obstruction (UUO). METHODS: Forty-eight male Sprague-Dawley rats were divided randomly into sham operation group and UUO model group with 24 rats each. The kidneys were excised on day 3, 7, and 14, and the deposition of collagen fiber in the kidneys was detected with HE and Masson staining. Immunohistochemical analysis was performed to evaluate the expression of Shh signaling pathway-related proteins, including Shh, Smo,Ptch1 and Gli1. The contents of TGF-β₁ and Shh in the kidney tissues were determined by ELISA. Real-time RT-PCR was used to detect the mRNA expression of TGF-β₁, Col I, Col III and Shh signaling-related genes.RESULTS: Fibrosis observed with HE and Masson staining was obviously increased in UUO kidneys, and aggravated as time prolonged. The contents of TGF-β₁, Col I and Col III were also increased. In addition, the expression of Shh, Smo and Gli1 was markedly increased in obstructive kidneys, and the expression of Ptch1 was decreased (P<0.01), suggesting that Shh signaling was activated. The level of Shh in UUO rats was associated with the content of TGF-β₁. CONCLUSION: Shh signaling is activated in the progress of renal interstitial fibrosis in UUO rats, and the possible mechanism triggering the fibrogenic response is that Shh signaling promotes the expression of TGF-β₁.     

Retinoic acid inhibits renal interstitial myofibroblast proliferation in a rat unilateral ureteral obstruction model

AIM: To investigate the effect of retinoic acid on proliferation of renal interstitial myofibroblasts in a rat model of the left unilateral ureteal obstruction (UUO). METHODS: UUO model was established by unilateral ligation of ureter in 36 SD rats. Rats were divided into 2 groups: Retinoic acid-treated group and control group, each with 18 rats. UUO rats were treated with either daily subcutaneous injection of 10 mg/kg body weight of all trans-retinoic acid or vehicle alone two days before the operation until being sacrificed. Groups of 6 rats were killed on day 3, 7 and 12 after ligation of the left ureter. The percentage of renal tubular lesion, interstitial fibrosis score, the number of interstitial myofibroblasts, the number of proliferating myofibroblasts and the expression of TGFβ-1 mRNA were determined. RESULTS: There were significant accumulation and local proliferation of myofibroblasts in the interstitium of the UUO rats. On day 7 of the UUO model, the percentage of tubular lesions and interstitial fibrosis score were significantly lower in the retinoic acid-treated group than those in control group[(15.9±2.0)%vs(27.3±2.2)%和(0.47±0.12)vs(1.65±0.18),P<0.01]. The numbers of interstitial myofibroblasts and proliferating myofibroblasts in the retinoic acid-treated group were significantly lower than those in the control group[(12.2±2.2)cells/HPF vs(29.5±1.8)cells/HPF和(1.4±0.6)cells/HPF vs(4.3±0.8)cells/HPF,P<0.01]. Furthermore, the expression of TGFβ-1 mRNA was significantly lower in the retinoic acid-treated group than that of the control group (P<0.01). CONCLUSION: Retinoic acid suppresses interstitial fibrosis in a rat UUO model by inhibiting the accumulation and local proliferation of myofibroblasts in the renal interstitium.     

Expression and functional role of p38 MAPK in the kidney after unilateral ureteral obstruction in rats

AIM: To investigate the expression and functional role of p38MAPK in the kidney after unilateral ureteral obstruction in rats. METHODS: Unilateral ureteral obstruction (UUO) models were induced by ligating the left ureter. Rats were sacrificed at 1 h, 3 h, 6 h, 12 h, 1, 3, 5, 7, 14, 21, and 28 days after UUO was initiated. p38MAPK activity was assayed by immunohistochemical staining and specific substrate phosphorylation with immunoprecipitation and Western blotting. TGFβ mRNA and protein expression were analyzed with in situ hybridization and immunohistochemical stainning. RESULTS: A basic p38MAPK activity was detectable in the normal kidney(0.22±0.06).p38MAPK pathway was rapidly act ivated at 1 hour(0.45±0.14 vs control,P<0.05)and this was steadily in creased by 12 hours(0.91±0.07 vs control,P<0.01)after UUO.Afterwards,the activity of p38MAPK reduced grad ually,then increased again from 3 days and this was steadily increased by 7 days(0.93±0.06 vs control,P<0.01). Upregulation of TGFβ₁ was markedly tested at 3 days(13.55±6.33 vs control,P<0.05)and this was steadily in creased by 7 days(26.78 8.77 vs control,P<0.01).The activation of p38MAPK preceded markedly the expression of TGF 1.The early activity of p38 MAPK was positively related to the amount of TGFβ₁ expression.The amount of TGFβ₁ expressed in obstructed kidney also related significant ly to the late activity of p38MAPK(r=0.84,P<0.01). CONCLUSION: The activity of p38MAPK is increased significantly in the obstructed kidney, which may cause renal fibrosis via inducing the expression of TGFβ₁.     

Ginsenoside Rh1 attenuates unilateral ureteral obstruction-induced renal interstitial fibrosis in rats

AIM:To observe the effects of ginsenoside Rh1 (G-Rh1) on unilateral ureteral obstruction (UUO)-induced renal interstitial fibrosis and to investigate the underlying mechanisms. METHODS:Male Sprague-Dawley (SD) rats (n=40) were divided into the following 4 groups:UUO-operated group (UUO group), sham-operated group (sham group), UUO-operated plus a low dose (50 mg·kg^-1·d^-1) of G-Rh1 treatment (low G-Rh1 group) and UUO-operated plus a high dose (100 mg·kg^-1·d^-1) of G-Rh1 treatment group (high G-Rh1 group). The G-Rh1 treatment was carried out by gastric gavage from the next day after the UUO operation once a day for 2 weeks (14 d). Immediately after the final dose of G-Rh1, 24 h urine was collected for the urine protein test, and then the rats were euthanized. The blood was collected for the blood urea nitrogen (BUN) and serum creatinine (SCr) assays, and the kidney was removed for pathological and biochemical evaluations. RESULTS:The levels of 24 h urine protein did not show any significant diffe-rence among the groups, while significantly increased levels of BUN and SCr in UUO group were observed (P<0.05), which was prevented by the treatment with G-Rh1 at both doses in a dose-dependent manner. Pathological evaluation showed the renal tissue damage was obvious in UUO group, which was improved by the treatment with G-Rh1 at both doses. Immunohistochemcial analysis exhibited that UUO increased renal interstitial transforming growth factor-β₁ (TGF-β₁) expression, which was also inhibited by the treatment with G-Rh1 at both doses(P<0.05). Significantly increased protein expression of renal interstitial collagen type I, α-smooth muscle actin (α-SMA) and connective tissue growth factor (CTGF) in UUO group was detected, which was suppressed by the treatment with G-Rh1 at both doses. CONCLUSION:G-Rh1 improves UUO-induced renal dysfunction and attenuates interstitial fibrosis, which is mediated via modulation of TGF-β₁-related pro-fibrogenic signaling pathway.     

Role of miR-219 and TGFBR2 in pathogenesis of renal fibrosis

AIM:To study the role of microRNA-219 (miR-219) in regulation of transforming growth factor-β receptor type 2 (TGFBR2) in renal fibrosis. METHODS:The renal fibrosis patients (n=70) were selected in this stu-dy, and 20 cases of healthy people were selected as control group. RT-qPCR was used to detect the expression of miR-219 in the serum of the patients with renal fibrosis and control group, and the expression of miR-219 in NRK49F cells after stimulation with angiotensin Ⅱ(AngⅡ) was detected. The protein expression of α-smooth muscle actin (α-SMA) in the NRK49F cells transfected with miR-219 mimics after stimulation with AngⅡ was determined by Western blot. The potential target gene TGFBR2 of miR-219 was screened and verified by the method of luciferase reporter gene. RT-qPCR and Western blot were used to detected the effect of miR-219 mimics on the expression of TGFBR2 at mRNA and protein levels, and the mRNA expression of α-SMA, connective tissue growth factor (CTGF), type I collagen α1 (COL1A1) and COL3A1 in the NRK49F cells was also detected, respectively. The unilateral ureteral occlusion (UUO) mouse model was established and the expression of miR-219 in the renal tissue was monitored. The morphological change of renal fibrosis was observed in the UUO mice after injection of miR-219, and the mRNA expression levels of COL1A1 and COL3A1 were detected. RESULTS:The expression level of miR-219 in the patients with renal fibrosis was significantly lower than that in control group, and the expression of miR-219 in the UUO mice was decreased significantly (P<0.01). The expression level of miR-219 was significantly decreased in the NRK49F cells after AngⅡ stimulation, and miR-219 mimics inhibited the protein expression of α-SMA(P<0.01). miR-219 mimics had a targeted regulatory effect on TGFBR2 gene, which inhibited the mRNA and protein expression of TGFBR2. miR-219 mimics inhibited the mRNA expression of α-SMA, CTGF, COL1A1 and COL3A1. miR-219 also down-regulated the mRNA expression of COL1A1 and COL3A1 in the UUO mice and inhibited the process of renal fibrosis. CONCLUSION:miR-219 inhibits the development of renal fibrosis by inhibiting the expression of TGFBR2, which may become a new target for the diagnosis and treatment of renal fibrosis.     

Effect of Chaihushugansan on pancreatic fibrosis in mice with chronic pancreatitis induced by DBTC plus ethanol and its anti-oxidation mechanism

AIM:To explore the role of superoxide dismutase (SOD) and malondialdehyde (MDA) in chronic pancreatitis (CP) induced by dibutyltin dichloride (DBTC) combined with ethanol, and the mechanisms for prevention and treatment of pancreatic fibrosis by Chaihushugansan. METHODS:The KM mice were randomly divided into control group, CP group (DBTC combined with ethanol) and Chaihushugansan group (CP+Chaihushugansan). Except for control group, the mice in other groups were intravenously injected in tail with DBTC (8 mg/kg) and drank 10% ethanol. The mice in Chaihushugansan group were administered intragastrically with Chaihushugansan (6 g·kg-1·d-1) at the following experimenal period. Before modeling and 1 week, 2 weeks, 4 weeks and 8 weeks after modeling, the mice were anesthetized and sacrificed. The activity of amylase and the content of hyaluronic acid in the serum were measured. The morphology and the degree of fibrosis in the pancreas were observed by HE staining. The activity of SOD and the level of MDA in the pancreas homogenate were analyzed. The protein of pancreas was extracted to detect the expression of type I collagen by Western blotting. RESULTS:DBTC combined with ethanol induced CP with increased serum amylase and hyaluronic acid levels， while the serum amylase and hyaluronic acid levels in Chaihushugansan group were significantly lowered (P<0.05). In 1 week, 2 weeks, 4 weeks and 8 weeks, the pancreas were obviously injured and appeared different degrees of fibrosis. The content of MDA and the expression of type I collagen in the increased significantly, but the SOD was decreased. In Chaihushugansan group, the pathological damage and the degree of fibrosis of the pancreas were improved. The level of MDA and type I collagen expression in the pancreas were significantly reduced, but the SOD was increased. CONCLUSION: The oxidative stress may take part in the development of CP. Inhibition of oxidative stress in the pancreas is one of the mechanisms that Chaihushugansan attenuates the development of CP.     

Effect of resveratrol on autophagy and renal interstitial fibrosis in kidney of diabetic mice

AIMTo observe the effect of resveratrol (Res) on renal autophagy level and renal interstitial fibrosis in the mice with diabetes mellitus (DM), and to discuss the possible mechanism. METHODSThe wild-type C57BL/6 mice were randomly divided into 3 groups, including normal control (NC) group, DM group and Res group (8 in each group). The diabetic mouse model was established by injection of streptozotocin. After 8 weeks of successful replication of the diabetic model, Res was given to the mice in Res group by continuous gavage for 12 weeks, and then the mice in each group were sacrificed to detect the relevant biochemical parameters. The pathological changes of the kidney tissues were observed by HE staining and Masson staining. The levels of the proteins related to autophagy, epithelial-mesenchymal transition (EMT) and fibrosis were determined by Western blot. The mRNA expression of collagen type IV (Col IV), α-smooth muscle actin (α-SMA) and E-cadherin were detected by real-time PCR. RESULTSCompared with NC group, fasting blood glucose (FBG), kidney index (KI), serum creatinine, 24-hour urinary albumin excretion rate and 24-hour urine total protein were remarkably increased in DM group (P<0.05). The results of HE and Masson staining indicated that renal tissue presented fibrosis in DM group. The protein levels of E-cadherin, beclin-1, microtubule-associated protein 1 light chain 3-II (LC3-II) were reduced in DM group, while the levels of α-SMA, Col IV and Snail1 were increased (P<0.05). After intervention with Res for 12 weeks, all the relevant biochemical parameters and KI were reduced (P<0.05) except FBG (P>0.05), and renal fibrosis lesions were obviously alleviated. Compared with DM group, the protein levels of E-cadherin, beclin-1 and LC3-II were increased in Res group, but the protein expression levels of α-SMA, Col IV, Snail1 were reduced (P<0.05). Compared with DM group, the mRNA level of E-cadherin was increased in Res group , but the mRNA levels of Col IV and α-SMA were reduced (P<0.05). CONCLUSION Resveratrol significantly inhibits EMT and reduces renal interstitial fibrosis in diabetic mice, and its mechanism may be related to the promotion of renal autophagy.     

Effect of Yiqi Huayu Huatan decoction on expression of KLF15, HMGB1, NF-κB and its downstream inflammatory factors in rats with UUO-induced renal interstitial fibrosis

AIM: To observe the effect of Yiqi Huayu Huatan decoction (YHHD) on unilaterral ureteral obstruction (UUO)-induced renal interstitial fibrosis in rats, and to investigate the possible mechanism. METHODS: Female SD rats (n=48) were randomly divided into sham group, model group, telmisartan group, and low-, middle-and high-dose YHHD groups, with 8 rats in each group. The UUO model rats was established by ligating left ureter. The rats in sham group and model group were treated with equal volume of normal saline, others were treated with the corresponding drugs daily. After 12 weeks, the rats were sacrificed. The serum samples were collected for determining the concentrations of cystatin C (Cys-C) and uric acid (UA). The morphological changes of the renal tissue were observed by PAS staining. The collagen fiber was observed by Masson staining. The mRNA expression of Krüppel-like factor 15 (KLF15), high-mo-bility group box protein 1 (HMGB1), nuclear factor-κB (NF-κB), IκB, monocyte chemotactic protein-1 (MCP-1), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), fibronectin (FN), collagen type I (Col I) and Col-Ⅳ was detected by real-time PCR. The protein expression of KLF15, HMGB1 and NF-κB was detected by Western blot. The protein expression of MCP-1 was determined by the method of immunohistochemistry. RESULTS: Compared with sham group, the deposition rate of collagen fibers and the concentration of Cys-C in model group were significantly increased (P<0.05), the mRNA and protein expression of KLF15 was significantly down-regulated (P<0.05), while the mRNA expression of HMGB1, NF-κB, IκB, MCP-1, IL-1β, TNF-α, FN, Col I and Col Ⅳ and the protein expression of HMGB1, NF-κB and MCP-1 were significantly up-regulated (P<0.05). Compared with model group, the deposition rates of collagen fibers in middle-and high-dose YHHD groups and telmisartan group were significantly decreased (P<0.05), with down-regulated protein expression of HMGB1 and NF-κB and mRNA expression of IL-1β and TNF-α (P<0.05). The protein expression of KLF15 was significantly up-regulated in high-dose YHHD group and telmisartan group (P<0.05), while the protein expression of MCP-1 and the mRNA expression of FN were significantly down-regulated (P<0.05). The mRNA expression of KLF15 was significantly up-regulated in high-dose YHHD group (P<0.05), while the mRNA expression of MCP-1, Col I and Col IV was significantly down-regulated (P<0.05). The mRNA expression of NF-κB and IκB was significantly down-regulated and the concentration of Cys-C was significantly decreased in each dose of YHHD groups and telmisartan group (P<0.05). No significant difference of UA level among the groups was observed. CONCLUSION: YHHD alleviates renal interstitial fibrosis in a dose-dependent manner, and YHHD at high dose shows the most obvious effect. The mechanism may be associated with the up-regulation of KLF15 and the down-regulation of HMGB1, NF-κB and its downstream inflammation-related factors in the renal tissue.     

Notch1 promotes renal tubulointerstitial fibrosis in renal tissues of diabetic mice by inhibiting autophagy through Akt/mTOR signaling pathway

AIM: To observe the changes of Notch1 expression and autophagy in the renal tissues of diabetic mice, and to explore the regulatory effect of Notch1 on tubulointerstitial fibrosis by inhibiting autophagy in diabetic nephro-pathy. METHODS: The mice were randomly divided into normal control group (db/m mice) and diabetes group (db/db mice), with 8 rats in each group. After 12 weeks of feeding, the mice were sacrificed and the corresponding biochemical indexes were measured. The protein expression of Notch1 in the renal tubular epithelial cells was observed by immunohistochemical staining. The protein levels of Notch1, PTEN, p-Akt (Thr308), Akt, p-mTOR (Ser2448), mTOR, LC3, P62, collagen type Ⅰ (Col-Ⅰ) and collagen type Ⅲ (Col-Ⅲ) were determined by Western blot. RESULTS: Compared with the db/m mice, the blood glucose, glycosylated hemoglobin, serum creatinine, triglyceride and total cholesterol were increased in the db/db mice (P<0.01). Renal tubular epithelial cell vacuolar degeneration, renal tubular expansion and interstitial inflammatory cell infiltration in db/db mouse renal tissues with HE staining were observed. The images of Masson staining showed collagenous fiber-like substance deposition in the glomerular capillaries and renal interstitium, and disarrangement of tubular structure in the renal tissues of db/db mice. The protein expression levels of PTEN and LC3-Ⅱ were decreased (P<0.01 or P<0.05), while the protein levels of Notch1, P62, p-mTOR (Ser2448), p-Akt (Thr308), Col-I and Col-III were increased in the db/db mice as compared with the db/m mice (P<0.01). However, no significant change of total mTOR and Akt proteins between the 2 groups was found. CONCLUSION: Notch1 protein expression was increased, PTEN expression was significantly reduced, Akt/mTOR pathway was activated, autophagy was inhibited, and fibrosis was aggravated in the renal tissues of the diabetic mice.     

COX-2 inhibitor protects rat heart against oxidative stress through a pathway independent of cyclooxygenase

AIM: To investigate whether nimesulide ［a selective cyclooxygenase 2 (COX-2) inhibitor］ and piroxicam (an inhibitor of COX-1) protect the rat hearts against oxidative stress induced by hydrogen peroxide,superoxide anion or hydroxyl free radical.METHODS: Cardiac contractility,lactate dehydrogenase (LDH) and malondialdehyde (MDA) were analyzed by the Langendorff method in isolated rat hearts.Production of 6-Keto-PGF1α,a marker of COX activity,was measured in isolated rat hearts.RESULTS: Rat hearts were exposed to hydrogen peroxide (H₂O₂),pyrogallol (which produced superoxide anion) or Vit C+Fe2+ (which produced hydroxyl free radical) for 10 min followed by reperfusion for 30 min.H₂O₂ decreased cardiac contractility and increased LDH release,which was inhibited by nimesulide (3 mg/kg) ［LVDP 72%±10% vs 61%±11%,LDH （5.5±2.5）U/L vs （8.0±2.1）U/L,P<0.05］.Piroxicam (3 mg/kg) increased systolic function (LVDP 73%±10% vs 61%±11%,P<0.05),but exacerbated diastolic function ［LVEDP （29.00±5.61）mmHg vs （23.16±3.57） mmHg,P<0.01］ in H₂O₂ treated rat hearts.Nimesulide also protected rat hearts against superoxide anion and hydroxyl free radical injury.Nimesulide and piroxicam had no effect on the content of 6-Keto-PGF_1α in rat hearts.Mitochondrial ATP sensitive potassium channel (mitoK_ATP) inhibitor 5-HD blocked the improvement of contractility (LVDP and ±dp/dt_max) induced by nimesulide in H₂O₂ treated rat hearts (53%±12% vs 69%±3%,58%±11% vs 72%±7% and 37%±8% vs 51%±4% respectively,P<0.01).CONCLUSION: The results suggests that COX-2 inhibitor nimesulide can protect rat hearts against oxidative injury.The protection is independent of COX activity.Activation of mitoK_ATP may be involved in nimsulide-induced cardioprotection in rat hearts.     

Comparison of in vivo anti-fibrotic effects of pirfenidone and nintedanib in bleomycin-induced pulmonary fibrosis model

AIM: To compare the effects of pirfenidone and nintedanib on bleomycin-induced mice pulmonary fibrosis model in different periods. METHODS: Five mice models were established according to the schedule of drug administration:a inflammatory phase model and 4 fibrotic phase models including the early prevention study group, early therapy study group, late therapy study group and full-course therapy study group. The indicators of lung inflammatory and lung fibrosis were detected respectively. RESULTS: (1) The level of anti-inflammatory and antioxidant indicators:both pirfenidone and nintedanib reduced the number of inflammatory cells and inhibited the secretion of inflammatory factors. Pirfenidone had a better effect on inhibition of interleukin (IL)-1β and IL-4 (P < 0.01), while nintedanib had a better effect on inhibition of IL-6 and IFN-γ (P < 0.05). Pirfenidone significantly increased superoxide dismutase (SOD) activity (P < 0.01), and nintedanib significantly reduced malondialdehyde (MDA) and myeloperoxidase (MPO) levels (P < 0.01). (2) Collagen content in lung tissue:the inhibitory effect of nintedanib on hydroxyproline content in mouse lung was better than that of pirfenidone in the early therapy study group, late therapy study group and full-course therapy study group of the fibrotic phase models (P < 0.05). Pirfenidone had a better inhibitory effect on hydroxyproline content than nintedanib in the early prevention study group (P < 0.01). (3) Pathological evaluation of lung tissue:both pirfenidone and nintedanib reduced the inflammatory infiltration and fibrotic area of the lung tissues. The inhibition trend was consistent with that of collagen content. CONCLUSION: Both pirfenidone and nintedanib have anti-inflammatory, anti-oxidative and anti-fibrosis effects in bleomycin-induced pulmonary fibrosis in mice. Pirfenidone is more effective in the early prevention study group, and nintedanib has a better effect in early therapy study group, late therapy study group and full-course therapy study group.     

Effects of Shenmai injection on myocardial fibrosis in rat model of diabe-tic cardiomyopathy

AIM：To explore the effects of Shenmai injection on myocardial fibrosis in a rat model of diabetic cardiomyopathy (DCM). METHODS：Wistar rats (n=30) were randomly divided into control group, diabetes group and treatment group. Single intraperitoneal injection of streptozotocin was utilized to establish a rat model of DCM. The rats with DCM in treatment group were intraperitoneally injected with Shenmai injection. Ventricular cannulation was applied to assess the cardiac functions. The formation of collagen in the cardiac tissues was assessed by Masson staining. The generation of reactive oxygen species (ROS) in the cardiac tissues was detected by dihydroethidium staining. The expression levels of matrix metalloproteinase 2 (MMP-2), tissue inhibitor of metalloproteinase 2 (TIMP-2) and collagen I in the cardiac tissues were determined by Western blotting. RESULTS：Compared with control group, the cardiac functions were deteriorated in diabetes group (P<0.05), which was improved in treatment group as compared with diabetes group (P<0.05). Compared with control group, the formation of collagen and ROS increased significantly in diabetes group (P<0.05), which was decreased in treatment group as compared with diabetes group (P<0.05). Compared with control group, the expression level of MMP-2 in the cardiac tissues was deceased and TIMP-2 was increased significantly in diabetes group (P<0.05), but reversed significantly in treatment group (P<0.05).CONCLUSION:Shenmai injection attenuates cardiac fibrosis in the rats with DCM by inhibiting the generation of ROS.     

Oxidative stress and P53 involve in fluctuant high glucose-induced apoptosis of renal tubular epithelial cells

AIM: To explore the mechanism of fluctuant high blood glucose-induced apoptosis of renal tubular epithelial cells. METHODS: Cultured human renal tubular epithelial cells (HK-2) were treated with stable high glucose or fluctuant high glucose. Antioxidant and specific inhibitor of P53 were applied for identifying the role of oxidative stress and P53 in fluctuant high glucose-induced apoptosis of renal tubular epithelial cells. Additionally, SD rats were randomly divided into normal control group (A), stable high blood glucose group (B) and fluctuant high blood glucose group (C). Diabetic rats were induced by intraperitoneal injection of streptozocin(STZ,65 mg/kg), and the fluctuant high blood glucose animal model was induced by intraperitoneal injection of ordinary insulin and glucose at different time points every day. The activity of superoxide dismutase (SOD) and the content of malonaldehyde (MDA) were detected by the method of colorimetry. The protein expression of NADPH oxidase 4(Nox4) and P53 were examined by immunohistochemistry and Western blotting. Apoptosis was assessed by flow cytometry and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL). RESULTS: The cultured HK-2 cells treated with fluctuant high glucose had significantly higher apoptotic rate and expression level of P53 protein than those in the cells treated with stable high glucose. Compared with the culture solution of the cels treated with stable high glucose, the SOD activity was decreased and the concentration of MDA was increased in the culture solution of the cells treated with fluctuant high glucose. The antioxidant and specific inhibitor of P53 significantly inhibited the p-P53 expression and decreased the apoptotic rate. After 12 experimental weeks, the cell apoptotic index and protein expression of Nox4 and p-P53 in the kidney tubular epithelial cells isolated from the diabetic rats were significantly increased in C group as compared with B group. CONCLUSION: Oxidative stress and P53 are involved in fluctuant high glucose-induced apoptosis of renal tubular epithelial cells.     

Expression and probable role of extracellular signal-regulated protein kinases in renal fibrosis associated with diabetic in mice

AIM: To investigate the expression and probable role of extracellular signal-regulated protein kinase (ERK1/2) in renal fibrosis associated with diabetic in mice.METHODS: Male homozygous C57BL/6 mice were divided at random into control group (intraperitoneally injected with citrate buffer) and diabetes group (received 5 consecutive daily intraperitoneal injections of streptozotocin at dose of 50 mg·kg^-1·d^-1).All mice were followed up for 16 weeks.Diabetes was confirmed by serum glucose levels exceeding 16.7 mmol/L.Mice were killed at 0,4,8,12 and 16 weeks respectively after streptozotocin injection.The kidney tissues were obtained from diabetic and control mice.Serum glucose,kidney weight/body weight (KW/BW),24 h albumin excretion rate (UAE) and the serum creatinine (Scr) were measured.The kidney tissue was used for histological and morphometric studies of glomerular size,glomerular matrix expansion (PAS),and the expression of TGF-β₁,phosphorylated ERK1/2 and collagen Ⅲ by immunohistochemical staining.RESULTS: The serum level of glucose in streptozotocin -induced diabetic mice increased significantly.The kidney weight/body weight ratio,glomerular volume and glomerular matrix expansion in diabetic mice were obviously higher than those in control mice.Serum creatinine and 24 h albumin excretion rate in diabetic mice increased significantly compared with control mice.TGF-β₁,phosphorylated ERK1/2 and collagen Ⅲ levels were obviously increased in the kidney of diabetic mice compared with those in control mice (P<0.01).TGF-β₁ expression was positively related to the expression of phosphorylated ERK1/2.CONCLUSION: The overexpression of phosphorylated ERK1/2 in diabetic kidney may play an important role in the development of renal fibrosis associated with diabetic nephropathy in mice.     

Expression and modulation of connective tissue growth factor in renal interstitial fibrosis

CTGF, a member of the CCN family of immediate early genes, is a recently discovered profibrotic growth factor, which is involved in many pathophysiologic procedures. CTGF acts as a downstream effector of TGF-β acting on interstitial cells to enhance the progression of fibrotic renal diseases. It has been shown that CTGF gene expression can be induced or blocked by some kinds of cytokine and drugs. It is an interesting candidate target for future intervention strategies of renal interstitial fibrosis.