AIM OF THE STUDY: This study aimed to elucidate the possible mechanism(s) of antidiarrhoeal activity of methanol leaf extract of Combretum hypopilinum (MECH) in mice.
MATERIALS AND METHODS: Phytochemical screening and acute toxicity study were conducted according to standard methods. Adult mice were orally (p.o) administered distilled water (10 ml/kg), MECH (1000 mg/kg) and loperamide (5 mg/kg). The probable mechanisms of antidiarrhoeal activity of MECH were investigated following pretreatment with naloxone (2 mg/kg, subcutaneously), prazosin (1 mg/kg, s.c), yohimbine (2 mg/kg, intraperitoneally), propranolol (1 mg/kg, i.p), pilocarpine (1 mg/kg, s.c) and isosorbide dinitrate (150 mg/kg, p.o) 30 min before administration of MECH (1000 mg/kg). The mice were then subjected to castor oil-induced intestinal motility test.
RESULTS: The oral median lethal dose (LD50) of MECH was found to be higher than 5000 mg/kg. There were significant (p
MATERIALS AND METHODS: Thirty five female Sprague Dawley rats at age 21-day old were divided into 4 groups; Group 1 (control, n=10), Group 2 (PF4, n=5), Group 3 (rapamycin, n=10) and Group 4 (rapamycin+PF4, n=10). MNU was administered intraperitionally, dosed at 70 mg/kg body weight. The rats were treated when the tumors reached the size of 14.5 ± 0.5 mm and subsequently sacrificed after 5 days. Rapamycin and PF4 were administered as focal intralesional injections at the dose of 20 μg/lesion. The tumor tissue was then subjected to histopathological examinations for morphological appraisal and immunohistochemical assessment of the pro-apoptotic marker, Bax and anti-apoptotic markers, Bcl-2 and survivin.
RESULTS: The histopathological pattern of the untreated control cohort showed that the severity of the malignancy augments with mammary tumor growth. Tumors developing in untreated groups were more aggressive whilst those in treated groups demonstrated a transformation to a less aggressive subtype. Combined treatment resulted in a significant reduction of tumor size without phenotypic changes. Bax, the pro-apoptotic marker, was significantly expressed at higher levels in the rapamycin-treated and rapamycin+PF4-treated groups compared to controls (p<0.05). Consequently, survivin was also significantly downregulated in the rapamycin-treated and rapamycin+PF4-treated group and this was significantly different when compared to controls (p).
CONCLUSIONS: In our rat model, it could be clearly shown that rapamycin specifically affects Bax and survivin signaling pathways in activation of apoptosis. We conclude that rapamycin plays a critical role in the induction of apoptosis in MNU-induced mammary carcinoma.
METHODS: BCR-ABL positive K562 CML cells were treated with TQ. Cytotoxicity was determined by Trypan blue exclusion assay. Apoptosis assay was performed by annexin V-FITC/PI staining assay and analyzed by flow cytometry. Transcription levels of BCR ABL, JAK2, STAT3, STAT5A and STAT5B genes were evaluated by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Protein levels of JAK2 and STAT5 were determined by Jess Assay analysis.
RESULTS: TQ markedly decreased the cell proliferation and induced apoptosis in K562 cells (P < 0.001) in a concentration dependent manner. TQ caused a significant decrease in the transcriptional levels of BCR ABL, JAK2, STAT3, STAT5A and STAT5B genes (P < 0.001). TQ induced a significant decrease in JAK2 and STAT5 protein levels (P < 0.001).
CONCLUSION: our results indicated that TQ inhibited cell growth of K562 cells via downregulation of BCR ABL/ JAK2/STAT3 and STAT5 signaling and reducing JAK2 and STAT5 protein levels.