All-Trans Retinoic Acid supplementation prevents cardiac fibrosis and cytokines induced by Methylglyoxal.

Methylglyoxal (MG), a metabolic intermediate of glycolysis is a precursor for endogeneous production of advanced glycation end-products. The increased production of MG have negative influence over the structure and function of different biomolecules and thus plays an important role in the pathogenesis of diabetic cardiac complications. Retinoic acid (RA), an active metabolite of vitamin A, has a major role in preventing cardiac remodeling and ventricular fibrosis. Hence, the objective of the present study was to determine whether rats administered with all-trans retinoic acid (RA) could attenuate MG induced pathological effects. Wistar rats were divided into 4 groups. Group 1 rats were kept as control; Group 2 rats were administrated with MG (75 mg/kg/day) for 8 weeks. Group 3 rats were given RA (Orally, 1.0 mg/kg/day) along with MG; Group 4 rats received RA alone. Cardiac antioxidant status, induction of fibrosis, AGE receptor (RAGE) and cytokines expression was evaluated in the heart tissues. Administration of MG led to depletion of antioxidant enzymes, induction of fibrosis (p < 0.001), up-regulated expression of RAGE (3.5 fold), TGF-ß (4.4 fold), SMAD2 (3.7 fold), SMAD3 (6.0 fold), IL-6 (4.3 fold) and TNF-α (5.5 fold) in the heart tissues compared to control rats. Moreover, the exogenous administration of MG caused significant (p < 0.001) increase in the circulating CML levels. Whereas, RA treatment prevented the induction of fibrosis and restored the levels of cytokines and RAGE expression. Methylglyoxal-induced fibrosis can lead to pathological effects in the heart tissues. RA attenuates the effects of MG in the heart, suggesting that it can be of added value to usual diabetic therapy.

Shensongyangxin protects against pressure overload­induced cardiac hypertrophy.

Shensongyangxin (SSYX) is a medicinal herb, which has long been used in traditional Chinese medicine. Various pharmacological activities of SSYX have been identified. However, the role of SSYX in cardiac hypertrophy remains to be fully elucidated. In present study, aortic banding (AB) was performed to induce cardiac hypertrophy in mice. SSYX (520 mg/kg) was administered by daily gavage between 1 and 8 weeks following surgery. The extent of cardiac hypertrophy was then evaluated by pathological and molecular analyses of heart tissue samples. In addition, in vitro experiments were performed to confirm the in vivo results. The data of the present study demonstrated that SSYX prevented the cardiac hypertrophy and fibrosis induced by AB, as assessed by measurements of heart weight and gross heart size, hematoxylin and eosin staining, cross­sectional cardiomyocyte area and the mRNA expression levels of hypertrophic markers. SSYX also inhibited collagen deposition and suppressed the expression of transforming growth factor ß (TGFß), connective tissue growth factor, fibronectin, collagen Ⅰα and collagen Ⅲα, which was mediated by the inhibition of the TGFß/small mothers against decapentaplegic (Smad) signaling pathway. The inhibitory action of SSYX on cardiac hypertrophy was mediated by the inhibition of Akt signaling. In vitro investigations in the rat H9c2 cardiac cells also demonstrated that SSYX attenuated angiotensin II­induced cardiomyocyte hypertrophy. These findings suggested that SSYX attenuated cardiac hypertrophy and fibrosis in the pressure overloaded mouse heart. Therefore, the cardioprotective effect of SSYX is associated with inhibition of the Akt and TGFß/Smad signaling pathways.

The potential of asiaticoside for TGF-ß1/Smad signaling inhibition in prevention and progression of hypoxia-induced pulmonary hypertension.

AIMS: Asiaticoside (AS) is a saponin monomer extracted from the medicinal plant Centella asiatica, which has a variety of biological effects. We intended to investigate the effects of asiaticoside on a hypoxia-induced pulmonary hypertension (HPH) rat model and examine the possible effects of asiaticoside on TGF-ß1/Smad signaling in vivo and in vitro. MAIN METHODS: The rat HPH model was established by hypoxic exposure and asiaticoside was administered for four weeks. Parameters including the mean pulmonary artery pressure (mPAP), the right ventricular hypertrophy (RVH) and the percentage of medial wall thickness were used to evaluate the development of HPH. TGF-ß1, TGF-ß receptor, Smad2/3 and phospho-Smad2/3 expressions were detected and the proliferation, migration and apoptosis of pulmonary arterial smooth muscle cells (PASMCs) adjusted by asiaticoside under the hypoxic condition were evaluated. KEY FINDINGS: Our data indicate that asiaticoside attenuated pulmonary hypertension, pulmonary vascular remodeling and RV hypertrophy in HPH rats, which was probably mediated by restraining the hypoxia-induced overactive TGF-ß1/Smad2/3 signaling and inhibiting the proliferation by inducing apoptosis of the PASMCs. SIGNIFICANCE: Given the preventative potential in animal models and in vitro, we propose asiaticoside as a promising protective treatment in HPH.

TGFß/Smad signalling in psoriatic epidermis models exposed to salt water soaks and narrowband ultraviolet B radiation.

The role of transforming growth factor-ß1 (TGFß1) and Smad signalling has not been established in psoriasis treatment. We aimed to investigate the effect of combined treatment with salt water soaks and ultraviolet radiation on the expression of TGFß1/Smad signalling proteins in a psoriatic model. We studied mRNA expression (real-time RT-PCR) of TGFß1, TGFß receptor type I (TGFßRI), Smad2, Smad3, Smad4, Smad7, minichromosome maintenance protein 7, and involucrin in normal as well as psoriatic epidermis models (PEM) which were treated for three consecutive days with differently concentrated salt water solutions [(3% NaCl; 30% NaCl, 30% Dead Sea salt water (DSSW)] and subsequent narrowband ultraviolet B (NB-UVB). In PEM, TGFß1 and Smad3 was significantly increased as compared to normal epidermis models. By contrast, TGFßRI mRNA was significantly decreased in PEM. Significant increase of mRNA levels of TGFß1, TGFßRI, Smad2 and Smad3 was predominantly observed in non-irradiated and irradiated PEM pre-treated with 30% NaCl and/or DSSW which was paralleled by increase of involucrin mRNA. In PEM pre-treated with DSSW, TGFßRI, Smad2, Smad3, Smad4, and Smad7 mRNA was significantly higher in irradiated PEM when compared to non-irradiated samples. It has been shown that TGFß1/Smad signalling is altered in a psoriatic model and may play a role in the mode of action of salt water soaks and NB-UVB phototherapy of psoriasis.

The TGF-ß1/Smad/CTGF pathway and corpus cavernosum fibrous-muscular alterations in rats with streptozotocin-induced diabetes.

Diabetes-associated erectile dysfunction is associated with increased extracellular matrix deposition and reduced smooth muscle content in the corpus cavernosum. The mechanisms of these processes are not well understood. In this study, we investigated fibromuscular changes in the corpus cavernosum of rats with streptozotocin-induced diabetes to determine the mechanisms underlying pathologic changes in penile structure and function. Forty 8-week-old Sprague-Dawley rats were randomly distributed into control and diabetic groups. Diabetes was induced by a one-time intraperitoneal injection of streptozotocin 60 mg/kg. Twelve weeks later, erectile function was measured by cavernous nerve electrostimulation with real-time intracorporal pressure assessment. The penis was harvested for histologic examination (Masson trichrome stain, picrosirius red stain, Hart elastin stain, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling, and immunohistochemistry) and Western blot. Diabetes significantly attenuated erectile response to cavernous nerve electrostimulation. Diabetic animals exhibited a decreased smooth muscle/collagen ratio in the corpus cavernosum. The ratio of collagen I to II fibers was significantly lower in the corpora of diabetic rats compared with controls. Cavernous elastic fibers were fragmented in diabetic rats. There was up-regulation of the transforming growth factor ß1/Smad/connective tissue growth factor signaling pathway in diabetic rats. Phospho-Smad2 expression was higher in smooth muscle cells and fibroblasts of diabetic rats, as was the apoptotic index. The up-regulation of the transforming growth factor ß1/Smad/connective tissue growth factor signaling pathway might play an important role in diabetes-induced fibrous-muscular structural changes and deterioration of erectile function.

[Effect of Kangxianling on Smads signal pathway molecules in rats with adriamycin induced nephropathy].

OBJECTIVE: To study the effect and mechanism of Kangxianling (KXL, a Chinese compound recipe) in treating adriamycin (ADR) induced renal fibrosis rats. METHODS: Forty-five male SD rats were randomly divided into 4 groups, the normal group (n = 7), the sham operative group (n = 8), the model group (n = 15), and the treatment group (n = 15). Model of renal interstitial fibrosis was established in rats by unilateral nephrectomy and intravenous injection of ADR twice at a 30-day interval, and the rats in the treatment group treated with KXL once a day for 72 days. Body weight, serum creatinine (SCr), blood urea nitrogen (BUN) levels and endogenous creatinine clearance rate (CCr) of animals were analyzed at the end of the 4th and the 8th week after operation. Rats were sacrificed after 72 days of treatment and their kidney obtained for pathological examination with HE and PASM staining. And protein expression levels of transforming growth factor beta (TGF-beta) receptor I (TbetaR I), TGF-beta receptor II (TbetaR II), Smad2 and Smad7 were determined by Western blotting. RESULTS: Levels of SCr and BUN in animals of the model group were significantly higher and CCr lower than those in the normal group (P < 0.05). Pathological examination of kidney in the model group showed thickened glomerular/tubular basement membrane with segmental sclerosis and hyaline degeneration; atrophy of the renal tubule around the sclerotic glomeruli and part of them disappeared; hypertrophy of partial glomeruli with surrounding severe dilated tubules; obvious glomeruli centering phenomena; severe tubular epithelial cell degeneration, necrosis with protein cast; fibrous tissue proliferation and large amount of inflammatory cell interstitial infiltration. The protein expression of TbetaR I and Smad2 in kidney tissue of the model group were significantly up-regulated, while that of TbetaR II and Smad7 unchanged. After KXL intervention, level of BUN lowered, SCr tended to normal and the endogenous SCr was raised to some degree. The renal pathological status in the treatment group was significantly improved and with markedly lowering of TbetaR I and Smad2 protein expression. CONCLUSION: KXL could inhibit the protein expression of TbetaR I and Smad2 in kidney tissue, so as to alleviate the renal fibrosis induced by adriamycin and improve the renal function.