Effects of thymosin β4 on neuronal apoptosis in a rat model of cerebral ischemia‑reperfusion injury

Effects of Thymosin β4 on Myocardial Apoptosis in Burned Rats

The aim of this study was to investigate the effects of thymosin β4 on myocardial apoptosis following burns. Fifty healthy Sprague Dawley (SD) rats were randomly divided into the normal control group, resuscitation group the low-dose Tβ4 (thymosin β4) group (2g), the medium-dose Tβ4 group (6g), and the high-dose Tβ4 group (18g). The rats were immersed in 95°C hot water for 18 seconds, and then the model of 30% body surface area (TBSA) III° scald was established. The resuscated rats were injected with lactate Ringer's solution for antishock rehydration, while the Tβ4 treatment group was injected with lactate Ringer's solution for antishock rehydration, and the animals were sacrificed 6 h after scald. The degree of histopathological damage was observed by HE (hematoxylin and eosin) staining. Western blot was used to detect STAT1 and STAT3 protein expression levels. Real-time PCR was used to detect mRNA expressions of STAT1 and STAT3. The results showed that the apoptosis rate of the resuscitation group was significantly higher than that of the control group (P < 0.01). Compared with the resuscitation group, the apoptosis rate of thymosin β4 in the treatment group was significantly reduced (P < 0.01). Compared with the normal control group, the expression of STAT1 protein was increased and the expression of STAT3 protein was decreased in model group rats after ischemia and reperfusion. Compared with the model group, the expression of STAT1 protein decreased and the expression of STAT3 protein increased after ischemia-reperfusion in the thymosin β4 treatment group. Thymosin β4 may protect the myocardium by downregulating STAT1 and upregulating STAT3 expression and inhibiting myocardial apoptosis induced by ischemia and reperfusion after severe scald injury.

Progress on the Function and Application of Thymosin β4

Thymosin β4 (Tβ4) is a multifunctional and widely distributed peptide that plays a pivotal role in several physiological and pathological processes in the body, namely, increasing angiogenesis and proliferation and inhibiting apoptosis and inflammation. Moreover, Tβ4 is effectively utilized for several indications in animal experiments or clinical trials, such as myocardial infarction and myocardial ischemia-reperfusion injury, xerophthalmia, liver and renal fibrosis, ulcerative colitis and colon cancer, and skin trauma. Recent studies have reported the potential application of Tβ4 and its underlying mechanisms. The present study reveals the progress regarding functions and applications of Tβ4.

Thymosin‑β 4 induces angiogenesis in critical limb ischemia mice via regulating Notch/NF‑κB pathway

Thymosin‑β 4 (Tβ4) has been reported to exert a pro‑angogenic effect on endothelial cells. However, little is known on the role and underlying mechanisms of Tβ4 on critical limb ischemia (CLI). The present study aimed therefore to investigate the mechanisms and pro‑angiogenic effects of Tβ4 in CLI mice. Tβ4 overexpression lentiviral vector was first transfected into HUVEC and CLI mice model, and inhibitors of Notch pathway (DAPT) and NF‑κB pathway (BMS) were also applied to HUVEC and CLI mice. Subsequently, MTT, tube formation and wound healing assays were used to determine the cell viability, angiogenesis and migratory ablity of HUVEC, respectively. Western blotting, reverse transcription, quantitative PCR, immunofluorescence and immunohistochemistry were used to detect the expression of the angiogenesis‑related factors angiopoietin‑2 (Ang2), TEK receptor tyrosine kinase 2 (tie2), vascular endothelial growth factor A (VEGFA), CD31 and α‑smooth muscle actin (α‑SMA) and the Notch/NF‑κB pathways‑related factors NOTCH1 intracellular domain (N1ICD), Notch receptor 3 (Notch3), NF‑κB and p65 in HUVEC or CLI mice muscle tissues. The results demonstrated that Tβ4 not only enhanced the cell viability, angiogenesis and migratory ability of HUVEC but also promoted the expression of Ang2, tie2, VEGFA, N1ICD, Notch3, NF‑κB, and phosphorylated (p)‑p65 in HUVEC. In addition, Tβ4 promoted the expression of CD31, α‑SMA Ang2, tie2, VEGFA, N1ICD and p‑p65 in CLI mice muscle tissues. Treatment with DAPT and BMS had opposite effects of Tβ4, whereas Tβ4 reversed the effect of DAPT and BMS. The findings from the present study suggested that Tβ4 may promote angiogenesis in CLI mice via regulation of Notch/NF‑κB pathways.