comparison between tocotrienol and omeprazole on gastric growth factors in stress-exposed rats

AIM To investigate and compare the effects of tocotrienol and omeprazole on gastric growth factors in rats exposed to water-immersion restraint stress(WIRS).METHODS Twenty-eight male Wistar rats were randomly assigned to four groups of seven rats. The two control groups were administered vitamin-free palm oil(vehicle) and the two treatment groups were given omeprazole(20 mg/kg) or tocotrienol(60 mg/kg) by oral gavage. After 28 d of treatment, rats from one control group and both treated groups were subjected to WIRS one time for 3.5 h. Gastric lesions were measured and gastric tissues were obtained to measure vascular endothelial growth factor(VEGF), epidermal growth factor(EGF), basic fibroblast growth factor(b FGF), and transforming growth factor-alpha(TGF-α) m RNA expression. RESULTS Rats exposed to WIRS for 3.5 h demonstrated the presence of considerable ulcers in the form of gastric erosion. The lesion index in the stressed control(S) group was increased(P < 0.001) compared to the tocotrienol treated and omeprazole treated groups. Stress led to a decrease in gastric VEGF(P < 0.001), b FGF(P < 0.001) and TGF-α(P < 0.001) m RNA levels and caused an increase in EGF m RNA(P < 0.001) that was statistically significant compared to the nonstressed control group. Although both treatment agents exerted similar ulcer reducing ability, only treatment with tocotrienol led to increased expression of VEGF(P = 0.008), b FGF(P = 0.001) and TGF-α(P = 0.002) m RNA.CONCLUSION Tocotrienol provides gastroprotective effects in WIRSinduced ulcers. Compared to omeprazole, tocotrienol exerts a similar protective effect, albeit through multiple mechanisms of protection, particularly through up-regulation of growth factors that assist in repair of gastric tissue injuries.

GAPDH expression as a measurement of transfection efficiency for p^16INK4agene silencing (siRNA) in senescent human diploid fibroblasts

Human diploid fibroblasts (HDFs) undergo a limited number of cell divisions in culture. After certain population doublings, they reach a state of irreversible growth arrest known as replicative senescence. Senescent HDFs showed several molecular and cytological changes such as large flat morphology, expression of senescence-associated β-galactosidase (SA β-gal) activity and altered gene expression. Small interfering RNA (siRNA) has been demonstrated to be a potential research tool to analyse gene function and pathway. Expression of an appropriate housekeeping or reference gene can be used as a measurement of transfection efficiency in siRNA. Therefore this study was designed to determine the suitability of GAPDH expression as a measurement of transfection efficiency for p16INK4a gene silencing in HDFs aging model. GAPDH knockdown with an appropriate transfection reagent was measured by quantitative real time RT-PCR while cellular senescence was characterized based on morphological changes, expression of SA β-gal and p16INK4a expression levels. Our findings showed that GAPDH knockdown represents silencing efficiency and down regulation of p16INK4a in senescent transfected HDFs caused morphological alterations which results in the formation of spindle shaped fibroblasts. This study demonstrated the suitability of GAPDH expression as a measurement of transfection efficiency for p16INK4a gene silencing in HDFs aging model.