RNA preparation and reverse transcription polymerase chain reaction (RT-PCR)
Gastric biopsy specimens were homogenized by using QIAshredder (QIAGEN) and total RNA was isolated using RNeasy mini spin column (QIAGEN) and subjected to semi-quantitative RT-PCR. Ten nanograms of total RNA was reversed transcribed and RT-PCR was performed using One-Step RT-PCR kit (QIAGEN) to detect IL-8, IL-1β, TNFα and Cox- 2 mRNA. Total RNA was reverse transcribed at 50 °C for 30 min, and 30 cycles of 45 s denaturation at 94 °C, 45 s of annealing at 64 °C and 1 min extension at 72 °C were employed. Primer sequences are shown in Table 1. PCR reaction products were electrophoresed on 2% agarose gel, stained with ethidium bromide and quantified by UV translumi- nator image documentation system using GeneSnap program. The levels of PCR products specific to cytokines were normalized relative to glyceraldehydes 3-phosphate dehydrogenase (GAPDH) amplicon.
Statistical analysis
Statistical analysis was performed using Fisher's exact test and t- test (paired and unpaired).