[Protective effect of Ligustri Lucidi Ait Polysaccharide against lipopolysaccharide-induced inflammatory injury of Sertoli cells in rats].

OBJECTIVE: To explore the effect of Ligustri Lucidi Ait Polysaccharide (LLP) on lipopolysaccharide (LPS)-induced inflammatory injury of Sertoli cells. METHODS: Rat Sertoli cells were isolated and cultured in vitro and then divided into five groups, blank control, LPS, LPS + low-dose LLP, LPS + medium-dose LLP, and LPS + high-dose LLP. After 48 hours of treatment, the proliferation of the cells was detected by CCK-8, their apoptosis determined by FMC, and the levels of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) activity and malondialdehyde (MDA) in the supernatant of the cell culture medium measured by ultraviolet spectrophotometry. The contents of IL-1α, IL-6 and TGF-ß in the culture medium were detected by ELISA before and after removal of LPS. RESULTS: The proliferation of the cells showed statistically significant differences among different groups (F = 153.93, P < 0.01), markedly reduced in the LPS group as compared with the blank control (P < 0.01), but remarkably increased in the high- and medium-dose LLP groups in comparison with the LPS group (both P < 0.01), and so did the apoptosis of the cells (F = 64.06, P < 0.01), significantly increased in the LPS group as compared with the blank control (P < 0.05), but markedly decreased in the high- and medium-dose LLP groups in comparison with the LPS group (both P < 0.01). Statistically significant differences were also observed among different groups in the levels of SOD (F = 56.07, P < 0.01), CAT (F = 41.57, P < 0.01), GSH-Px activity (F = 238.46, P < 0.01), and MDA (F = 285.31, P < 0.01), with decreased SOD, CAT and GSH-Px activity (P < 0.01) and increased MDA (P < 0.01) in the LPS group as compared with the control, but elevated SOD and CAT in the high- and medium-dose LLP groups and increased GSH-Px activity and decreased MDA concentration in all the three LLP groups in comparison with the LPS group (P < 0.01). Before the removal of LPS, the contents of IL-1α, IL-6 and TGF-ß in the culture medium were markedly higher in the LPS than in the control group (all P < 0.01), that of IL-1α was increased significantly in the high- and medium-dose LLP groups (P < 0.01 and P < 0.05) while those of IL-6 and TGF-ß showed no statistically significant differences in the three LPS groups as compared with the LLP group (P > 0.05). After the removal of LPS, the contents of IL-1α and IL-6 were remarkably reduced (t = 25.26 and 61.43, P < 0.01) and that of TGF-ß increased (t = －18.16, P < 0.01), even more significantly in the LLP+LPS groups (P < 0.01). CONCLUSIONS: Ligustri Lucidi Ait Polysaccharide plays a protective role in LPS-induced inflammatory injury of Sertoli cells by reducing cell apoptosis and regulating the contents of IL-1α, IL-6 and TGF-ß from Sertoli cells in inflammation.

Akt associates with nuclear factor kappaB and plays an important role in chemoresistance of gastric cancer cells.

The ubiquitously expressed serine-threonine kinase Akt and the transcription factor NF-kappaB both are involved in cell proliferation and apoptosis. Furthermore, the activation of Akt or NF-kappaB has been suggested to associate with chemo-resistance of human tumors. The exact mechanism and interreaction of Akt and NF-kappaB pathway on chemoresistance in gastric cancer is still unknown. We explored the function of Akt and NF-kappaB pathway on chemoresistance in human gastric cancer cells. MTT method was used to analyze the influence of chemotherapeutics and the combined use of wortmannin or MG-132 on the growth of SGC-7901 cells. Apoptosis of SGC-7901 was detected by TUNEL and Annexin V/PI methods. The protein level of NF-kappaB was analyzed by immunocytochemical staining. EMSA was used to confirm the increased nuclear translocation of RelA. The protein level of p-Akt and p-IkappaBalpha were analyzed by Western blotting. Etoposide and doxorubicin suppressed the growth of SGC-7901 time and dose-dependently. Combined use of wortmannin or MG-132 can suppress growth further. Chemotherapeutics induced apoptosis of SGC-7901 and activated Akt and NF-kappaB, combined use of wortmannin or MG-132 induced apoptosis further and attenuated the activation of NF-kappaB. The combined use of wortmannin attenuated the activation of Akt, but combined use of MG-132 did not attenuate the activation of Akt. The activation of NF-kappaB is a branch mechanism of Akt anti-apoptosis effects. The chemotherapeutics induced apoptosis and induced the activation of Akt and NF-kappaB in SGC-7901 cell, suppression the activation of Akt or NF-kappaB can increase the effects of chemotherapeutics. NF-kappaB is a downstream target of Akt.

Melatonin reduces inflammatory injury through inhibiting NF-kappaB activation in rats with colitis.

Proinflammatory mediators are important in the pathogenesis of IBD, which are regulated by activation of NF-kappaB. The aim of this study was to investigate whether melatonin reduces inflammatory injury and inhibits proinflammatory molecule and NF-kappaB in rats with colitis. Rat colitis model was established by TNBS enema. NF-kappaB p65, TNF-alpha, ICAM-1, and IkappaBalpha in colon tissue were examined by immunohistochemistry, EMSA, RT-PCR, and Western blot analysis. Expression of proinflammatory molecule and activation of NF-kappaB were upregulated and IkappaB level decreased in rats with colitis. Melatonin reduces colonic inflammatory injury through downregulating proinflammatory molecule mediated by NF-kappaB inhibition and blockade of IkappaBalpha degradation.

Effects of garlicin on apoptosis in rat model of colitis.

AIM: To investigate the effects of garlicin on apoptosis and expression of bcl-2 and bax in lymphocytes in rat model of ulcerative colitis (UC). METHODS: Healthy adult Sprague-Dawley rats of both sexes, weighing 180+/-30 g, were employed in the present study. The rat model of UC was induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS) enema. The experimental animals were randomly divided into garlicin treatment group (including high and low concentration), model control group, and normal control group. Rats in garlicin treatment group and model control group received intracolic garlicin daily at doses of 10.0 and 30.0 mg/kg and equal amount of saline respectively 24 h after colitis model was induced by alcohol and TNBS co-enema. Rats in normal control group received neither alcohol nor only TNBS but only saline enema in this study. On the 28th d of the experiment, rats were executed, the expression of bcl-2 and bax protein was determined immunohistochemically and the apoptotic cells were detected by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate fluorescence nick end labeling (TUNEL) method. At the same time, the rat colon mucosal damage index (CMDI) was calculated. RESULTS: In garlicin treatment group, the positive expression of bcl-2 in lymphocytes decreased and the number of apoptotic cells was more than that in model control group, CMDI was lower than that in model control group. The positive expression of bax in lymphocytes had no significant difference. CONCLUSION: Garlicin can protect colonic mucosa against damage in rat model of UC induced by TNBS enema.

Expression and significance of nuclear factor kappaB p65 in colon tissues of rats with TNBS-induced colitis.

AIM: To investigate the role of NF-kappaB in the pathogenesis of TNBS-induced colitis in rats. METHODS: Thirty-two healthy adult Sprague-Dawley (SD) rats were randomly divided into four groups of eight each: normal, NS, model I, model II groups in our study. Rat colitis model was established through 2-,4-,6-trinitrobenzene sulfonic acid (TNBS) enema. At the end of four weeks, the macroscopical and histological changes of the colon were examined and mucosa myeloperoxidase (MPO) activities assayed. NF-kappaB p65 expression was determined by Western blot assessment in cytoplasmic and nuclear extracts of colon tissue, and the expressions of TNF-alpha and ICAM-1 protein in colon tissue were examined by immunohistochemistry. The relativities between expression of NF-kappaB p65 and other parameters were analyzed. RESULTS: TNBS enema resulted in pronounced pathological changes of colonic mucosa in model II group (macroscopic and histological injury indices 6.25+/-1.39 and 6.24+/-1.04, respectively), which were in accordance with the significantly elevated MPO activity (1.69+/-0.11). And the nuclear level of NF-kappaB and expression of TNF-alpha, ICAM-1 in rats of model II group were higher than that of normal control (9.7+/-1.96 vs 1.7+/-0.15, 84.09+/-14.52 vs 16.03+/-6.21, 77.69+/-8.09 vs 13.41+/-4.91 P<0.01), Linear correlation analysis revealed that there were strong correlations between the nuclear level of NF-kappaB and the tissue positive expression of TNF-alpha and ICAM-1, MPO activities, macroscopical and histological indices in TNBS-induced colitis, respectively (r = 0.8235, 0.8780, 0.8572, 0.9152, 0.8247; P<0.05). CONCLUSION: NF-kappaB plays a pivotal role in the pathogenesis of ulcerative colitis, which might account for the up-regulation the expression of TNF-alpha and ICAM-1.