Estudo da morfologia e status oxidativo em rim de ratos com nefropatia isquêmica após tratamento com células-tronco mesenquimais de tecido adiposo / Study of morphology and oxidative status in kidney of rats with ischemic nephropathy after treatment with adipose tissue mesenchymal stem cells

A nefropatia isquêmica é uma doença renal crônica provocada pela redução do fluxo sanguíneo renal que pode progredir para a doença renal terminal, cujo tratamentos disponíveis se baseiam em terapias substitutivas da função renal, como diálise ou transplante renal. No entanto, devido ao alto custo dos tratamentos e a carência de órgãos, se faz necessária a busca por novas terapias, como as células-tronco (CT). Apesar do potencial terapêutico das CT em doenças crônicas, não está claro se essas células mantêm seus efeitos benéficos em órgãos lesionados por tempo prolongado. O objetivo desse estudo foi avaliar os efeitos precoces e tardios do tratamento com células-tronco adiposas (CTA) sobre a morfologia e o status oxidativo em rins de ratos com nefropatia isquêmica. A isquemia renal foi induzida pelo modelo 2rins-1clip (2R1C) e, depois de um mês da clipagem da artéria renal, foram injetadas 106 células-tronco na região subscapsular do rim afetado. Após 15 e 30 dias da injeção das CTA, a morfologia renal foi verificada por meio da análise macroscópica, microscópica e ultraestrutural. Além disso, o status oxidativo foi avaliado no tecido renal através da mensuração da atividade das enzimas antioxidantes catalase e glutationa peroxidase; e de marcadores biológicos de dano oxidativo, como proteínas carboniladas, 3-Nitrotirosina e 4-Hidroxinonenal. Por imunoperoxidase foi possível localizar as células-tronco adiposas GFP+ foram rastreadas e encontradas tanto 15 dias, quanto 30 dias após a injeção na região subcapsular. A restauração da arquitetura renal foi evidenciada 15d após o uso das células, onde detectamos redução na deposição de fibras colágenas no parênquima renal, o que não foi observado 30d após o uso das células. Os resultados também foram confirmados através da análise da ultraestrutura renal que mostraram restauração da arquitetura renal no grupo de 15d, não evidenciada no grupo de 30d. Quanto a análise do status oxidativo, somente os animais com nefropatia isquêmica mais prolongada apresentaram estresse oxidativo com redução da atividade da enzima antioxidante catalase no tecido renal. Além disso, foi observado dano proteico e lipídico, sem melhora dessa condição nos animais 30d após o tratamento com as células-tronco. No modelo de nefropatia isquêmica avaliado, o tratamento com CTA mostrou benefícios na morfologia renal a curto prazo, mas não tardiamente, apesar da permanência dessas células no tecido. Acreditamos que o estresse oxidativo, evidenciado somente no tecido renal com isquemia mais prolongada, possa ter dificultado a ação das células-tronco, contribuindo para tais achados. Esses resultados abrem perspectivas para o aprofundamento do estudo quanto à caracterização dos mecanimos de ação das CTA nas respostas anti-fibrogênicas, assim como o estabelecimento do número, frequência, vias de administração e melhor momento para uso dessas células no tratamento de doenças renais crônicas.

Ischemic nephropathy is a chronic kidney disease caused by reduced kidney blood flow that can progress to end stage kidney disease, whose available treatments are based on kidney function replacement therapies, such as dialysis or kidney transplantation. However, due to the high cost of treatments and the lack of organs, it is necessary to search for new therapies, such as stem cells (SC). Despite the therapeutic potential of SC in chronic diseases, it is unclear whether these cells maintain their beneficial effects on injured organs for a long time. The aim of this study was to evaluate the early and late effects of adipose-derived stem cells (ADSC) treatment on the morphology and oxidative status in kidneys of rats with ischemic nephropathy. Renal ischemia was induced by the 2kidneys-1clip (2K1C) model and, after a month of clipping the renal artery, 106 stem cells were injected into the subscapsular region of the affected kidney. After 15 and 30 days of ADSC injection, renal morphology was verified by macroscopic, microscopic, and ultrastructural analysis. In addition, oxidative status was assessed in renal tissue by measuring the activity of the antioxidant enzymes catalase and glutathione peroxidase; and biological markers of oxidative damage, such as carbonylated proteins, 3-nitrotyrosine and 4-hydroxynonenal. By immunoperoxidase, it was possible to locate GFP + adipose-derived stem cells that were tracked and found both 15 days and 30 days after injection in the subcapsular region. The restoration of the renal architecture was evidenced 15d after the use of the cells, where we detected a reduction in the deposition of collagen fibers in the renal parenchyma, which was not observed 30d after the use of the cells. The results were also confirmed by analyzing the renal ultrastructure, which showed restoration of the renal architecture in the 15d group, not evidenced in the 30d group. Regarding the analysis of oxidative status, only animals with more prolonged ischemic nephropathy presented oxidative stress with reduced activity of the antioxidant enzyme catalase in renal tissue. In addition, protein and lipid damage was observed, with no improvement in this condition in the animals 30d after treatment with stem cells. In the evaluated ischemic nephropathy model, treatment with ADSC showed benefits in renal morphology in the short term, but not late, despite the permanence of these cells in the tissue. We believe that oxidative stress, evidenced only in renal tissue with more prolonged ischemia, may have hindered the action of stem cells, contributing to such findings. These results open perspectives for further study on the characterization of ADSC mechanisms of action in anti-fibrogenic responses, as well as the establishment of the number, frequency, routes of administration and the best time to use these cells in the treatment of chronic kidney diseases.

Flax lignan concentrate attenuate hypertension and abnormal left ventricular contractility via modulation of endogenous biomarkers in two-kidney-one-clip (2K1C) hypertensive rats

ABSTRACT The present investigation was designed to study the effect of flax lignan concentrate obtained from Linum usitatissimum L., Linaceae, in two-kidney, one clip (2K1C) hypertension model in Wistar rats. 2K1C Goldblatt model rats were divided randomly into six groups: sham, 2K1C control, captopril (30 mg/kg), flax lignan concentrate (200, 400 and 800 mg/kg). Flax lignan concentrate and captopril were administered daily for eight consecutive weeks. Sham-operated, and 2K1C control rats received the vehicle. Treatment with flax lignan concentrate (400 and 800 mg/kg) significantly and dose-dependently restored the hemodynamic parameters systolic blood pressure, diastolic blood pressure, mean arterial blood pressure and left ventricular functions. The flax lignan concentrate significantly restored the elevated hepatic, renal and cardiac marker enzymes in the serum. It also restored the organs weights (kidney and heart), serum electrolyte level and histological abnormalities. Furthermore, flax lignan concentrate significantly elevated the level of biochemical markers that is enzymatic antioxidants superoxide dismutase, glutathione and decreased malondialdehyde in the heart and kidney tissues. Meanwhile, we found that plasma nitric oxide and plasma nitric oxide synthase contents were significantly increased in the flax lignan concentrate-treated group, and plasma endothelin-1 and renal angiotensin-II levels were significantly lower than 2K1C hypertensive group. In conclusion, the antihypertensive and antioxidant effect of flax lignan concentrate were dose-dependent and at the highest dose (i.e. 800 mg/kg) similar to those of captopril (30 mg/kg). It is suggested that flax lignan concentrate reduced blood pressure by reduction of renal angiotensin-II level, inhibition of plasma endothelin-1 production, induction of the nitric oxide, nitric oxide synthase and in vivo antioxidant defense system.

Effects of hydrogen sulfide on arterial vasodilatation function of renal hypertensive rats / 中国药理学通报

Aim To investigate the modulation effects of NaHS on arterial vasodilatation functions of renal hy-pertensive rats .Methods Two-kidney , one-c lip ( 2K1C ) renovascular hypertension was induced .Rats were randomly divided into four group:sham group , two-kidney one-clip model ( 2K1C ) group, 2KIC +NaSH( H2 S donor ) group, PPG group.The systolic blood pressure ( SBP ) was measured before the opera-tion and each week after the operation .The carotid ar-tery was collected for morphometric parameters ( outer radius, wall thickness, the radio of wall thickness to outer radius) and the tension of the carotid artery was observed with the isolated artery ring technique .Immu-nohistochemistry was used to determine the protein ex-pression of eNOS , ET-1 protein in carotid artery .Re-sults The blood pressure of 2K1C group and PPG group was higher than that of sham group ( P<0.05) . Compared with 2K1C group,the blood pressure and the rat arteria carotis communis of the radio of wall thick-ness to outer radius of 2K1C+NaHS group decreased significantly , while the relaxation of carotid artery to ACh in NaHS group increased .According to the immu-nohistochemistry results , eNOS expression was upregu-lated while ET-1 was downregulated in 2K1C +NaHS group as compared with 2K1C group.Conclusions Chronical administration of NaHS can decrease blood pressure in renovasocular hypertensive rats .The anti-hypertensive effect of H 2 S maybe associated with im-provement of the arterial functions .

Epidermal growth factor receptor involvement in cardiovascular remodeling in renovascular hypertensive rats / 中国药理学通报

Aim To determine the possibilities and mechanisms of EGFR, a receptor protein tyrosine kinase associated with many important cellular processes re-sponsible for cardiovascular remodeling in renovascular hypertensive rats. Methods 2K1C hypertensive rats were used in the present study. Blood pressure was measured with the tail-cuff method. LVMI and his-topathological changes in the cardiovascular system were analysed. EGFR expressions of aorta and myocar-dium as well as phosphorylation levels of ERK in hy-pertensive rats were detected by immunohistochemistry and Western blot analysis, respectively. Results Sys-tolic blood pressure was markedly increased 2 weeks after 2K1C surgery. Cardiovascular remodeling induced by hypertension was confirmed by elevated LVMI, pro-liferation of collagen fibers in myocardial interstitium, histopathological changes in cardiovascular system and increased IMT of thoracic aorta 6 weeks after 2 K1 C surgery. Compared with sham rats, EGFR expression in the ventricular myocardium of 2 K1 C rats was signifi-cantly increased at 6 weeks ( P<0. 05 ) , and the EG-FR/GAPDH ratio was higher in 2 K1 C rats with higher systolic blood pressure ( P < 0. 05 ) . Phosphorylation level of ERK 1/2 was upregulated correspondingly in 2 K1 C rats ( P <0. 01 ) . Increased EGFR expression was also found in aortas of 2K1C rats, particularly in tunica intima and media. Conclusion EGFR and its down-stream kinases ERK 1/2 are involved in cardio-vascular remodeling in association with the severity of hypertension in renovascular hypertensive rats.

Time-course effects of aerobic exercise training on cardiovascular and renal parameters in 2K1C renovascular hypertensive rats

Exercise training (Ex) has been recommended for its beneficial effects in hypertensive states. The present study evaluated the time-course effects of Ex without workload on mean arterial pressure (MAP), reflex bradycardia, cardiac and renal histology, and oxidative stress in two-kidney, one-clip (2K1C) hypertensive rats. Male Fischer rats (10 weeks old; 150–180 g) underwent surgery (2K1C or SHAM) and were subsequently divided into a sedentary (SED) group and Ex group (swimming 1 h/day, 5 days/week for 2, 4, 6, 8, or 10 weeks). Until week 4, Ex decreased MAP, increased reflex bradycardia, prevented concentric hypertrophy, reduced collagen deposition in the myocardium and kidneys, decreased the level of thiobarbituric acid-reactive substances (TBARS) in the left ventricle, and increased the catalase (CAT) activity in the left ventricle and both kidneys. From week 6 to week 10, however, MAP and reflex bradycardia in 2K1C Ex rats became similar to those in 2K1C SED rats. Ex effectively reduced heart rate and prevented collagen deposition in the heart and both kidneys up to week 10, and restored the level of TBARS in the left ventricle and clipped kidney and the CAT activity in both kidneys until week 8. Ex without workload for 10 weeks in 2K1C rats provided distinct beneficial effects. The early effects of Ex on cardiovascular function included reversing MAP and reflex bradycardia. The later effects of Ex included preventing structural alterations in the heart and kidney by decreasing oxidative stress and reducing injuries in these organs during hypertension.

Combined aliskiren and L-arginine treatment has antihypertensive effects and prevents vascular endothelial dysfunction in a model of renovascular hypertension

Angiotensin II is a key player in the pathogenesis of renovascular hypertension, a condition associated with endothelial dysfunction. We investigated aliskiren (ALSK) and L-arginine treatment both alone and in combination on blood pressure (BP), and vascular reactivity in aortic rings. Hypertension was induced in 40 male Wistar rats by clipping the left renal artery. Animals were divided into Sham, 2-kidney, 1-clip (2K1C) hypertension, 2K1C+ALSK (ALSK), 2K1C+L-arginine (L-arg), and 2K1C+ALSK+L-arginine (ALSK+L-arg) treatment groups. For 4 weeks, BP was monitored and endothelium-dependent and independent vasoconstriction and relaxation were assessed in aortic rings. ALSK+L-arg reduced BP and the contractile response to phenylephrine and improved acetylcholine relaxation. Endothelium removal and incubation with N-nitro-L-arginine methyl ester (L-NAME) increased the response to phenylephrine in all groups, but the effect was greater in the ALSK+L-arg group. Losartan reduced the contractile response in all groups, apocynin reduced the contractile response in the 2K1C, ALSK and ALSK+L-arg groups, and incubation with superoxide dismutase reduced the phenylephrine response in the 2K1C and ALSK groups. eNOS expression increased in the 2K1C and L-arg groups, and iNOS was increased significantly only in the 2K1C group compared with other groups. AT1 expression increased in the 2K1C compared with the Sham, ALSK and ALSK+L-arg groups, AT2 expression increased in the ALSK+L-arg group compared with the Sham and L-arg groups, and gp91phox decreased in the ALSK+L-arg group compared with the 2K1C and ALSK groups. In conclusion, combined ALSK+L-arg was effective in reducing BP and preventing endothelial dysfunction in aortic rings of 2K1C hypertensive rats. The responsible mechanisms appear to be related to the modulation of the local renin-angiotensin system, which is associated with a reduction in endothelial oxidative stress.

Expression of MMP-9 and the intervention effect of telmisartan on vascular remodeling of 2K1C Hypertension Rats / 中国基层医药

Objective To explore the expression and mechanisms of MMP-9 in vascular remodeling of two-kidney and one-cliped hypertension rats. Methods Male Wistar rats were randomly divided into sham operation group( n = 10), two-kidney and one-clip model (2KIC) group ( n = 10) and telmisartan group ( n = 7 ). Telmisartan group were injected with telmisartan every day. The blood pressure was determined every week. The morphologic change of carotid artery and thoracic aorta was observed with HE stainning 8 weeks after treatment with telmisartan.Arteries was performed to evaluate the expression of MMP-9 with immunohistochemisty. Results The blood pressure,vessel wall,and the expression of MMP-9 in model group were significantly higher than that of control group.Telmisartan nearly normalized arterial pressure and suppressed all these changes. Conclusion MMP-9 was related to vascular remodeling and Telmisartan could regulate vascular remodeling in 2-kidney and 1-cliped hypertension rats by inhibiting the pathway of MMP-9.