Oxidative stress disturbs energy metabolism of mitochondria in ethanol-induced gastric mucosa injury

Abstract

Aim: To study the role of mitochondrial energy disorder in the pathogenesis of ethanol-induced gastric mucosa injury.

Methods: Wistar rats were used in this study. A gastric mucosal injury model was established by giving the rats alcohol. Gross and microscopic appearance of gastric mucosa and ultrastructure of mitochondria were evaluated. Malondiadehyde (MDA) in gastric mucosa was measured with thiobarbituric acid. Expression of ATP synthase (ATPase) subunits 6 and 8 in mitochondrial DNA (mtDNA) was determined by reverse transcription polymerase chain reaction (RT-PCR).

Results: The gastric mucosal lesion index was correlated with the MDA content in gastric mucosa. As the concentration of ethanol was elevated and the exposure time to ethanol was extended, the content of MDA in gastric mucosa increased and the extent of damage aggravated. The ultrastructure of mitochondria was positively related to the ethanol concentration and exposure time. The expression of mtDNA ATPase subunits 6 and 8 mRNA declined with the increasing MDA content in gastric mucosa after gavage with ethanol.

Conclusion: Ethanol-induced gastric mucosa injury is related to oxidative stress, which disturbs energy metabolism of mitochondria and plays a critical role in the pathogenesis of ethanol-induced gastric mucosa injury.

Figure 1

Gross appearance of gastric mucosa in rats with ethanol-induced acute gastric mucosa injury 2 h after administration of normal sodium (A), 40% (W/W) ethanol (B), 70% (W/W) ethanol (C), and 100% (W/W) ethanol (D), respectively.

Figure 2

Histological changes in gastric mucosa of rats with ethanol-induced acute gastric mucosa injury (× 100) 2 h after administration of normal sodium (A), 40% (W/W) ethanol (B), 70% (W/W) ethanol (C), and 100% (W/W) ethanol (D), respectively.

Figure 3

Gross changes in gastric mucosa of rats with ethanol-induced chronic gastric mucosa injury 3 wk after administration of normal sodium (A), 25% (W/W) ethanol (B), and 45% (W/W) ethanol (C), respectively; 6 wk after administration of normal sodium (D), 25% (W/W) ethanol (E), and 45% (W/W) ethanol (F), respectively; 9 wk after administration of normal sodium (G), 25% (W/W) ethanol (H), and 45% (W/W) ethanol (I), respectively.

Figure 4

Histological changes in gastric mucosa of rats with ethanol-induced chronic gastric mucosa injury (HE stain) 3 wk after administration of normal sodium (A), 25% (W/W) ethanol (B), and 45% (W/W) ethanol (C), respectively; 6 wk after administration of normal sodium (D), 25% (W/W) ethanol (E), and 45% (W/W) ethanol (F), respectively; 9 wk after administration of normal sodium (G), 25% (W/W) ethanol (H), and 45% (W/W) ethanol (I), respectively.

Figure 5

Changes in mitochondrial ultra-structure of rats with ethanol-induced acute gastric mucosa injury 2 h after administration of normal sodium (A), 40% (W/W) ethanol (B) 70% (W/W) ethanol (C), and 100% (W/W) ethanol (D), respectively. Arrows indicate swollen and collapsed mitochondria and dissolved and diminished mitochondrial cristae.

Figure 6

Changes in mitochondrial ultra-structure of rats with ethanol-induced chronic gastric mucosa injury 3 wk after administration of normal sodium (A), 25% (W/W) ethanol (B), and 45% (W/W) ethanol (C), respectively; 6 wk after administration of normal sodium (D), 25% (W/W) ethanol (E), and 45% (W/W) ethanol (F), respectively; 9 wk after administration normal sodium (G), 25% (W/W) ethanol (H), and 45% (W/W) ethanol (I), respectively.

Figure 7

RT-PCR for expression of mtDNA ATPase subunits 6 and 8 mRNA in rates with ethanol-induced acute gastric mucosa injury. M: 100 bp DNA ladder was a RT-PCR product of β-actin mRNA (upper row, 300 bp); lanes 1-4: RT-PCR products of mtDNA ATPase subunit 6 mRNA after treatment with normal sodium, 40% (W/W) ethanol, 70% (W/W) ethanol, and 100% (W/W) ethanol, respectively; lanes 5-8: RT-PCR products of mtDNA ATPase subunit 8 mRNA after treatment with normal sodium, 40% (W/W) ethanol, 70% (W/W) ethanol, and 100% (W/W) ethanol, respectively.

Figure 8

RT-PCR for expression of mtDNA ATPase subunit 6 mRNA in rats with ethanol-induced chronic gastric mucosa injury. M: 100 bp DNA ladder of RT-PCR products of β-actin mRNA (upper row, 300 bp); lanes 1-9: RT-PCR products of mtDNA ATPase subunit 6 mRNA 3 wk after treatment with normal sodium, 25% (W/W) ethanol, and 45% (W/W) ethanol, respectively; 6 wk after treatment with normal sodium, 25% (W/W) ethanol, and 45% (W/W) ethanol, respectively; 9 wk after treatment with normal sodium, 25% (W/W) ethanol, and 45% (W/W) ethanol, respectively.

Figure 9

RT-PCR for expression of mtDNA ATPase subunit 8 mRNA in rats with ethanol-induced chronic gastric mucosa injury. M: 100 bp DNA ladder of RT-PCR products of β-actin mRNA (upper row, 300 bp); lanes 1-9: RT-PCR products of mtDNA ATPase subunit 8 mRNA 3 wk after treatment with normal sodium, 25% (W/W) ethanol, and 45% (W/W) ethanol, respectively; 6 wk after treatment with normal sodium, 25% (W/W) ethanol, and 45% (W/W) ethanol, respectively; 9 wk after treatment with normal sodium, 25% (W/W) ethanol, and 45% (W/W) ethanol, respectively.