Lycium barbarum polysaccharide attenuates cardiac hypertrophy, inhibits calpain‑1 expression and inhibits NF‑κB activation in streptozotocin‑induced diabetic rats

Abstract

Cardiac hypertrophy is one of the key structural changes that occurs in diabetic cardiomyopathy. Previous studies have indicated that the activation of NF-κB by calpain-1, a Ca 2+ -dependent cysteine protease, serves an important role in cardiac hypertrophy. The aim of the present study was to assess the effect of 30 and 60 mg/kg Lycium barbarum polysaccharide (LBP) treatment, the major active ingredient extracted from Lycium barbarum , on cardiac hypertrophy in streptozotocin (STZ) induced diabetic rats. In addition, the present study examined the possible underlying mechanisms of this effect by assessing calpain-1 expression and the NF-κB pathway. The mRNA expression of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) was determined by reverse transcription-quantitative PCR. Western blotting was used to detect the protein expressions of calpain-1, interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), intercellular adhesion molecule-1 (ICAM-1), vascular adhesion molecule-1 (VCAM-1) and toll-like receptor-4 (TLR-4) in the heart tissue. The results revealed that compared with non-diabetic rats, diabetic rats exhibited cardiac hypertrophy. Cardiac hypertrophy was defined by the following: Dysfunction of the cardiac hemodynamics, an increase in the ratios of left ventricular weight/body weight and heart weight/body weight and the increased expressions of ANP and BNP, which serve as hypertrophic markers in cardiac tissue. However, all of these changes were attenuated in diabetic rats treated with LBP. In addition, the protein expression of calpain-1 was increased in the heart tissue of diabetic rats compared with that of non-diabetic rats, where it was inhibited by LBP. LBP also decreased the protein expression of certain inflammatory mediators, IL-6, TNF-α, ICAM-1, VCAM-1 and TLR-4 in diabetic heart tissue. Furthermore, LBP treatment reduced the production of reactive oxygen species, upregulated the protein expression of endothelial nitric oxide synthase and downregulated the protein expression of inducible nitric-oxide synthase. Additionally, LBP increased the protein expression of p65, the subunit of NF-κB and inhibitory protein кB-α in the cytoplasm and reduced p65 expression in the nucleus. In conclusion, LBP improves cardiac hypertrophy, inhibits the expression of calpain-1 and inhibits the activation of NF-κB in diabetic rats.

Curcumin and its analog alleviate diabetes-induced damages by regulating inflammation and oxidative stress in brain of diabetic rats

“…Meanwhile, there was some data manifesting that curcumin could decrease serum TNF-α levels in diabetes rats [ 36 ]. According to the results of Western blot and IHC staining in this study, we can conclude that p65 mainly works by entering the nucleus in the cerebral cortex of diabetic rats which is consistent with previous findings [ 37 ]. Similarly, curcumin or A13 could effectively reduce the level of p65 in the nucleus of diabetes rat.…”

Curcumin and its analog alleviate diabetes-induced damages by regulating inflammation and oxidative stress in brain of diabetic rats​

“…Meanwhile, there was some data manifesting that curcumin could decrease serum TNF-α levels in diabetes rats [36]. According to the results of Western blot and IHC staining in this study, we can conclude that p65 mainly works by entering the nucleus in the cerebral cortex of diabetic rats which is consistent with previous ndings [37]. Similarly, curcumin or A13 could effectively reduce the level of p65 in the nucleus of diabetes rat.…”

Lycium barbarum polysaccharides inhibit ischemia/reperfusion-induced myocardial injury via the Nrf2 antioxidant pathway

“…LBP, a member of the Solanaceae, is the major active ingredient extracted from Lycium barbarum and contains 6 monosaccharides, galactose, rhamnose, glucose, mannose, arabinose, xylose and 18 different amino acids, and exerts a large variety of beneficial effects, such as immunomodulation, anti‑inflammation and anti-aging [ 31 ]. Recently study further demonstrated that LBP attenuated cardiac hypertrophy and improved cardiac function in diabetic rats [ 32 ]. Accordingly, we speculated that LBP might play important cardioprotective roles in myocardial I/R rats by inhibiting oxidative stress.…”