[Effects of glutathione on plasma heat shock protein 70 of acute gastric mucosal injury in rats exposed to positive acceleration].

Objective: To explore the change of plasma heat shock protein 70 (HSP70) in rats exposed to acute gastric mucosal injury under the condition of positive acceleration (+Gz) and elucidate the effects of glutathione (GSH) and the corresponding protective mechanisms.

Methods: A total of 40 male SD rats were randomly by computer randomization into 4 groups of ethanol control, +5 Gz value exposure, +10 Gz value exposure and GSH protection (n = 10 each). GSH protection group received adaptive feeding for 7 days and then an intraperitoneal injection of GSH for 3 consecutive days. All 4 groups fasted for 24 hours within 10 days, water deprivation for 12 hours and a gastric lavage of anhydrous ethanol (0.4 ml/100 g) for 1 hour, ethanol control group had no acceleration,+5 Gz value exposure group at + 5 Gz and the latter two groups respectively at +10 Gz for around 3 min.Each group underwent anesthesia of pentobarbital after centrifuge immediately. Abdominal aortic blood samples were collected and gastric tissues harvested for observation of mucosal injury. Mucosal damage index was calculated by the GUTH method. And the plasma content of HSP70 was measured by radioimmunoassay.

Results: (1) Gastric mucosa of each groups rats were injured. Damage was significantly reduced by GSH pretreatment, ethanol control group had less injury, the injury of +5 Gz value exposure group was aggravated compared with the control group (gastric mucosal injury index: 25.4 (14.0-30.0) vs 10.0 (9.2-13.9), P = 0.001); +10 Gz value exposure group mucosal injury was heaviest (47.2 (41.5-60.1)) . There were diffuse hyperemia, edema and erosion with a large area of bleeding spots and flat mucosal folds.It had statistically significant differences with the first two groups (all P < 0.01); GSH protection group was lightest at 9.5 (7.5-14.1). Compared with the +10 Gz value exposure group, mucosal damage was milder (P < 0.01).(2) The plasma levels of HSP70 of +5 Gz value exposure had no significant differences with the control and ethanol groups ((6.5 ± 0.5) ng/ml, P = 0.897); HSP70 plasma level ((5.9 ± 0.5) ng/ml) of +10 Gz value exposure was significantly lower than those of the first two groups (P = 0.018,0.014); GSH protection group ((7.0 ± 0.5) ng/ml) was significantly higher than the level of +10 Gz value exposure group (P < 0.01).

Conclusions: +Gz exposure may cause the altered levels of plasma HSP70.High +Gz value exposure reduces its content and aggravates gastric mucosal injury. And glutathione reduces the injury of gastric mucosa through elevated plasma HSP70.