Sleep deprivation increase the expression of inducible heat shock protein 70 in rat gastric mucosa

Acute sleep deprivation preconditions the heart against ischemia/ reperfusion injury: the role of central GABA-A receptors

OBJECTIVES

Central γ-aminobutyric acid (GABA) neurotransmission modulates cardiovascular functions and sleep. Acute sleep deprivation (ASD) affects functions of various body organs via different mechanisms. Here, we evaluated the effect of ASD on cardiac ischemia/reperfusion injury (IRI), and studied the role of GABA-A receptor inhibition in central nucleus of amygdala (CeA) by assessing nitric oxide (NO) and oxidative stress.

MATERIALS AND METHODS

The CeA in sixty male Wistar rats was cannulated for saline or bicuculline (GABA-A receptor antagonist) administration. All animals underwent 30 min of coronary occlusion (ischemia), followed by 2 hr reperfusion (IR). The five experimental groups (n=12) included are as follows: IR: received saline; BIC+IR: received Bicuculline; MLP+IR: received saline, followed by the placement of animals in an aquarium with multiple large platforms; ASD+IR: underwent ASD in an aquarium with multiple small platforms; and BIC+ASD+IR: received bicuculline prior to ASD.

RESULTS

Bicuculline administration increased the malondialdehyde levels and infarct size, and decreased the NO metabolites levels and endothelial nitric oxide synthase (eNOS) gene expression in infarcted and non-infarcted areas in comparison to IR group. ASD reduced malondialdehyde levels and infarct size and increased NO metabolites, corticosterone levels and eNOS expression in infarcted and non-infarcted areas as compared to the IR group. Levels of malondialdehyde were increased while levels of NO metabolites, corticosterone and eNOS expression in infarcted and non-infarcted areas were reduced in the BIC+ASD+IR as compared to the ASD+IR group.

CONCLUSION

Blockade of GABA-A receptors in the CeA abolishes ASD-induced cardioprotection by suppressing oxidative stress and NO production.

Relationship between heat shock protein 70 and stress ulcer

Biologic cells produce a series of stress reaction after being attacked by various kinds of physical and chemical factors, which induces the expression of heat shock proteins (HSPs). As the most conservative protein of HSPs, HSP70 family was studied most. Stress can induce gastric mucosal damage and reduce the protective function of mucosal barrier, resulting in the formation of stress ulcer. At the same, stress can accelerate the synthesis of HSP70, but in turn, HSP70 can prevent the occurrence of stress ulcer, inhibit the apoptosis of gastric mucosal cells and promote the healing of gastric ulcer. In this article, we reviewed the regulation and main classification of HSPs, the expression of HSPs and its role in stress ulcer, and several drugs (targeting on the induction of HSP expression) for the protection of gastric mucosa.

Protective effect of HSP70 on gastric mucosal cells against apoptosis

AIM: To investigate whether HSP70 can protect gastric mucosal cells from apoptosis induced by chronic emotional stress.

METHODS: Seventy mice were randomly devided into control group (n = 16), heat shock stress group (HS, n = 18), psychological stress group (PS, n = 18), heat shock stress plus psychological stress group (HPS, n = 18). Mice in HS, PS and HPS groups were subjected to heat shock stress, psychological stress, and heat shock stress plus psychological stress respectively. Apoptosis of gastric mucosal cells and the expression level of HSP70 were detected by TUNEL technique and immunohistochemical staining respectively after 1, 2, and 3 mo.

RESULTS: After 1 mo, apoptotic cells among the 4 groups were not significant. After 2 mo, apoptotic rate in PS group was significantly higher than control group (3.7 ± 1.9% vs 1.3 ± 1.4%, P = 0.017 < 0.05), SH group (3.7 ± 1.9% vs 1.2 ± 1.6%, P = 0.010 < 0.05), and HPS group (3.7 ± 1.9% vs 1.3 ± 1.1%, P = 0.012 < 0.05). After 3 mo, apoptotic rate in PS group was significantly higher than that in control group (4.1 ± 3.9% vs 1.0 ± 1.1%, P = 0.025 < 0.05), HS group (4.1 ± 3.9% vs 0.4 ± 0.7%, P = 0.009 < 0.05), and HPS group (4.1 ± 3.9% vs 1.4 ± 1.5%, P = 0.046 < 0.05). After 1 mo, HSP70 level was significantly higher in HS group and HPS group than that in control group (64 ± 11% vs 20 ± 11%, P = 0.00 < 0.05; 72 ± 6% vs 20 ± 11%, P = 0.00 < 0.05) and psychological stress group (64 ± 11% vs 34 ± 15%, P = 0.00 < 0.05; 72 ± 6% vs 34 ± 15%, P = 0.00 < 0.05). After 2 mo, HSP70 level was significantly higher in HS and HPS group than that in control group (84 ± 13% vs 25 ± 15%, P = 0.00 < 0.05; 87 ± 7% vs 25 ± 15%, P = 0.00 < 0.05) and PS group (84 ± 13% vs 46 ± 30%, P = 0.02 < 0.05; 87 ± 7% vs 46 ± 30%, P = 0.01 < 0.05). After 3 mo, HSP70 level was also significantly higher in HS and HPS group than those in control group (61 ± 16% vs 16 ± 9%, P = 0.02 < 0.05; 65 ± 29% vs 16 ± 9%, P = 0.01 < 0.05) and PS group (61 ± 16% vs 33 ± 29%, P = 0.09 < 0.05; 65 ± 29% vs 33 ± 29 %, P = 0.046 < 0.05). HSP70 level was negatively correlated with apoptotic rate of gastric mucosal cells (r = -0.320, P = 0.008 < 0.05).

CONCLUSION: Chronic emotional stress can induce apoptosis of gastric mucosal cells while HSP70 can protect them from apoptosis.

Computer-assisted visualization and quantitation of experimental gastric lesions in rats

INTRODUCTION

Photography is commonly used to evaluate macroscopic morphology of experimental gastric lesions. The conventional methods for quantitation of these lesions tend to be highly subjective, error-prone, and tedious. This study reports a simple and novel method for visualization of experimental gastric lesions by direct scanning of stomach samples and their quantitation by using computer-assisted image analysis.

METHODS

Gastric mucosal lesions were produced by indomethacin or ethanol in male Wistar rats. The stomachs were removed, opened along the greater curvature, and washed. The flattened stomach samples were sandwiched within a transparent plastic folder and scanned. The captured image was saved and subjected to lesion quantitation using a freely accessible image analysis program, Scion Image. A macro subroutine was optimized for automation of the entire procedure for ease in frequent applications.

RESULTS

The images obtained by direct scanning of stomach samples showed excellent morphologic visualization of gastric lesions. The standard spots having variable areas of same density, or same areas of variable densities, showed a direct relation with signal intensity (pixels). A linear correlation was observed between measured and actual values of the known standard areas. The representative samples of indomethacin- and ethanol-induced gastric ulcers showed the total lesion areas of 4.62+/-0.74 and 169.26+/-13.23 mm(2), respectively.

DISCUSSION

Direct scanning of stomach samples is a simple, cost-effective, rapid, and efficient procedure for morphologic evaluation of experimental gastric lesions. The output images of scanned stomach samples are superior to scanned photographs, and can be instantly used for quantitative assessment of mucosal injury using the image analysis program.

Significance of changes of gastrointestinal peptides in blood and ileum of experimental spleen deficiency rats

AIM: To explore the mechanism of spleen deficiency (SD) by studying the relationship of gastro-intestinal peptides level and ileal electro-mechanical activity of SD rats and cold restrain rats.

METHODS: (1) spleen deficiency (SD) model was established by feeding Houpou:Zhishi: Dahuang in the ratio of 3:3:2, 3 ml/time, for 42 days. (2) The cold restrain stress model: Animals were restrained on grille and placed in a cool water at 18 °C for 3 h. (3) Substance P (SP) and vasoactive intestinal peptide (VIP) levels in all layers of initial part of ileum and blood in rats were measured by radioimmunoassays (RIA) while changes of electric activity and motility in ileum of rats were recorded with electrode and strain gauge.

RESULTS: SP levels in ileum and blood of experimental SD rats were significantly higher than that of the control groups (9.89 ± 5.65 vs 1.22 ± 1.18, P < 0.005, in ileum; 22.7 ± 3.95 vs 6.60 ± 1.47, P < 0.001, in blood) while the VIP levels of the SD rats were significantly lower than that of the controls (3.50 ± 2.01 vs 9.10 ± 4.91, P < 0.05, in ileum; 229.8 ± 62.4 vs 560.4 ± 151.3, P < 0.001, in blood). As compared with the controls, the average frequency of slow electric waves (21.3 ± 0.96 vs 18.2 ± 2.28, P < 0.05) and motility (21.5 ± 0.58 vs 18 ± 2.65, P < 0.005) of SD rats increased obviously and the frequency of fast waves of SD rat also increased. In spontaneous recovery cases, SP levels recovered significantly (compared with the SD groups, 2.99 ± 0.62 vs 9.89 ± 5.65, P < 0.001, in ileum; 14.4 ± 4.22 vs 22.7 ± 3.95, P < 0.001, in blood) but did not drop to normal. After the SD rats treated with Chinese herbs (Jiawei Sijun zi Tang), SP improved (compared with SD cases, 2.20 ± 1.25 vs 9.89 ± 5.65, (P < 0.001), in ileum; 10.7 ± 1.88 vs 22.7 ± 3.95, (P < 0.001), in blood) and VIP in blood also improved (compared with SD rats, 485.7 ± 229.0 vs 229.8 ± 62.4, P < 0.01) while the amplitude of motility decreased apparently (compared with the SD rats, 0.64 ± 0.096 vs 0.89 ± 0.15, P < 0.01). The ileal SP levels of cool stress didn’t change while the ileal VIP levels of cool stress became significantly lower than that of the control groups (2.87 ± 0.87 vs 9.10 ± 4.91, P < 0.01). The blood SP levels of cool stress were significantly higher (15.60 ± 1.83 vs 6.60 ± 1.47, P < 0.001) whereas the blood VIP levels of cool stress were significantly lower than that of the control group (153.4 ± 70.46 vs 560.4 ± 151.30, P < 0.001).

CONCLUSION: Changes of SP and VIP levels in initial part of ileum and blood of SD rats and cool stress rats may be closely related to the gastrointestinal motility disorders presented in SD and cool stress rats. the Chinese herbs (Jiawei Sijun zi Tang) currently used have partially therapeutic effect.