БИОЛОгические науки/5.Молекулярная биология

Dvorshchenko K.O., Dranitsina A.S., Ostapchenko L.I.

Taras Shevchenko Kyiv National University, Kyiv, Ukraine

Expression of Gast and ChgA genes in rat liver during long-term gastric hypochlorhydria and its correction with administration of multiprobiotic

Long-term gastric hypoacidity is accompanied by disturbance of the digestive processes, dysbiosis, hypergastrinemia, and is one of the risk factor of gastric tumors [1]. Long-term inhibition of gastric acid secretion can causes pathological changes in liver cells. Firstly, gastric hypochlorhydria reduces the stimulating effect of cholecystokinin and secretin (which are excreted to the duodenum under the influence of hydrochloric acid) on bile secretion. Secondly,

bacterial infections with reduced gastric acidity can be cause of metabolic liver diseases. According to a scientific literature, expression of Gast and ChgA genes is associated with development of neuroendocrine tumors, including liver [2, 3].

Formerly we have shown that multiprobiotic "Symbiter acidophilic" concentrated (“Symbiter”) prevented morphological changes in liver, evoked by prolonged hypoacidity. Multiprobiotic “Symbiter” – the concentrated biomass of living cells of multicomponent symbiotic probiotic bacteria (Bifidobacterium, Lactobacillus, lactic streptococci and propionic acid bacteria).

The aim of the study was to determine the expression of Gast and ChgA genes in rat liver in conditions of long-term hypoacidity, evoked by omeprazole and the effect of multiprobiotic “Symbiter” on this process.

Materials and methods. Experiments were carried out on white non-strain male rats with initial weight around 180-200 g. All animals were divided into four groups. Rats injected abdominally with 0,2 ml of physiological solution and 0,5 ml of water for injections orally were used as a control (first group). Animals of second group were treated with the same dose of “Symbiter” orally (0,14 ml/kg) during 28 days. Hypoacidity (third group) was modeled by everyday intraperitoneal injection of omeprazole (14 mg/kg) during 28 days. Fourth experimental group simultaneously with omeprazole obtained “Symbiter” orally (0,14 ml/kg). Number of animals in each experimental group was 7.

Total RNAs from rat liver were isolated accordingly to modification of the procedure of Chomczynski et al. (1987). The expression of above mentioned genes was analyzed by semiquantitative RT-PCR. Statistical processing of experimental data was performed with analysis of varience. Probability of difference between control and test measurements was assessed with Student’s t-test.

Results and discussion. mRNA of Gast and ChgA genes was not detected in rat liver of control group and the group of rats injected with “Symbiter” (Fig. 1, 2).

Fig. 1. Level of gastrin mRNA in rat liver upon long-term gastric hypochlorhydria and with administration of multiprobiotic “Symbiter”.

М – molecular mass marker; 1 – control; 2 – Symbiter; 3 – omeprazole; 4 – omeprazole + Symbiter; N-PCR – negative PCR control.

At the same time, upon long-term gastric hypoacidity expression of this genes was observed, since its mRNA was revealed in the samples of rat livers. It was shown that prolonged inhibition of gastric secretion of hydrochloric acid by omeprazole caused appearance of Gast and ChgA genes expression in liver (Fig. 1, 2).

At combined introduction of animal “Symbiter” with omeprazole, the expression of Gast and ChgA genes decreased by 3.1 and 1.2 times accordingly relative to the group of rats injected with omeprazole (Fig. 1, 2).

Fig. 2. Level of chromogranin A mRNA in rat liver upon long-term gastric hypochlorhydria and with administration of multiprobiotic “Symbiter”.

М – molecular mass marker; 1 – control; 2 – Symbiter; 3 – omeprazole; 4 – omeprazole + Symbiter; N-PCR – negative PCR control.

The long-term hypoacidity of gastric juice is accompanied with the changes in expression of Gast and ChgA genes in the liver tissue that indicates the potential risk of cell transformation. Symbiter promoted

partial restoration of the investigated genes in liver via normalization microbiota in the gastrointestinal tract and diminishing of serum gastrin level.

Literature.

1. Canani R., Terrin G. Gastric acidity inhibitors and the risk of intestinal infections // Curr. Opin. Gastroenterol. – 2010. – Vol. 26, №1. – P. 31-35.

2. Harris J., Gilliam A., McKenzie A. et al. The biological and therapeutic importance of gastrin gene expression in pancreatic adenocarcinomas // Cancer Res. – 2004. – Vol. 64. – P. 5624-5631.

3. Massironi S., Fraquelli M., Paggi S. et. al. Chromogranin A levels in chronic liver disease and hepatocellular carcinoma // Dig. Liver. Dis. – 2009. – Vol. 41, №1. – P. 31-35.