الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 182 |  |  |
| | | from | 182 | | |
Abstract
The current study aims to evaluate the in vitro and in vivo anti-carcinogenic activity of two brown seaweed Turbinaria ornata and Padina pavonia ethanolic extracts against AOM-induced carcinogenesis in mice. In addition, the suppressive effect of these extracts against the adverse effects of AOM in liver and kidney has been investigated.
Materials and methods:
Total phenolic content in both algal extract was estimated. For in vitro study, cytotoxic activity of the Turbinaria ornata and Padina pavonia ethanolic extracts were evaluated against HCT-116 cell line using cell viability assay.
For in vivo study, Twenty four mice were used to study the protective effects of the brown seaweeds, T. ornata and P. pavonia, against AOM-induced colon carcinogenesis. Colon carcinogenesis was induced by intraperitoneal injections of 10 mg/kg AOM once a week for two consecutive weeks. According to the study protocol, animals were divided into four groups as follows:
group 1 (Control): Mice received two intraperitoneal injections of saline and orally administered the vehicle 1% carboxymethylcelluose (CMC).
group 2 (AOM): Mice received AOM and orally administered 1% CMC.
group 3 (AOM + T. ornata): Mice received AOM + 100 mg/kg body weight T. ornata extract suspended in 1% CMC.
group 4 (AOM + P. pavonia): Mice received AOM + 100 mg/kg body weight P. pavonia extract suspended in 1% CMC.
At the end of experiment, mice were anesthetized by ether inhalation and blood samples were collected. Collected blood samples were left to coagulate then centrifuged at 3000 rpm for 15 minutes to separate serum. Colon, liver and kidney samples were excised and immediately perfused with ice-cold saline. Frozen tissue samples (10% w/v) were homogenized in chilled saline and the homogenates were centrifuged using Centurion Scientific K3 cooling centrifuge (UK) to separate the nuclear debris. Aliquots of the clear homogenate were prepared and used for determination of different biochemical markers. Colon, liver and kidney samples were flushed with saline and then fixed in 10% buffered formalin for at least 24 h. After fixation, the specimens were dehydrated in ascending series of ethanol, cleared in xylene, and embedded in paraffin wax. Blocks were made and 4μm thick sections were cut by a sledge microtome. The paraffin embedded liver tissue sections were deparaffinised using xylene and ethanol. The slides were washed with phosphate buffered saline (PBS) and stained with hematoxylin and eosin (H&E). The stained slides were examined under light microscope. Other colon and liver samples were frozen in liquid nitrogen and kept for RNA isolation.
Results:
The amount of total phenolics in T. ornata was significantly higher than in P. pavonia. Both extracts showed in vitro anti-proliferative efficacy; T. ornata seemed to be more potent. Both extracts demonstrated marked cytotoxicity but T. ornata was more potent than P. pavonia. The results revealed significant elevation in colon, liver and kidney lipid peroxidation and NO levels in the AOM-induced group compared to the normal control mice. Oral administration of both algal extracts significantly decreased lipid peroxidation and NO levels in the AOM-induced mice compared to the AOM-induced control mice. On the contrary, GSH content in colon, liver and kidney of the AOM-induced mice showed a significant decrease when compared to the non-induced mice. Oral administration of T. ornata as well as P. pavonia markedly alleviated GSH levels when compared to AOM-induced mice; T. ornata produced more potent effect. Similarly, SOD and GPx activities of the AOM-induced mice were significantly reduced compared to untreated control mice. Oral administration of either T. ornata or P. pavonia produced a significant elevation of SOD and GPx activity.
Both PPARγ and p53 were significantly downregulated and NF-B was markedly upregulated in the colon and liver of AOM-induced mice compared to the untreated control mice. Oral supplementation of either T. ornata or P. pavonia produced a significant upregulation in the expression of PPARγ and p53 compared to AOM-induced control mice, whereas NF-B mRNA expression was significantly downregulated. Supplementation of either T. ornata or P. pavonia extracts to AOM-administered mice produced marked improvement in the colon, liver and kidney architecture.
Treatment of mice with AOM induced marked impairment of liver function evidenced by a significant elevation of serum AST and ALT compared to normal mice. Oral supplementation of T. ornata as well as P. pavonia significantly ameliorated the altered serum aminotransferases. Similarly, total bilirubin concentration revealed a significant increase in serum of AOM-administered mice when compared to the normal ones. Treatment of AOM-induced mice with T. ornata and P. pavonia markedly decreased the elevated serum bilirubin levels; T. ornata seemed to be more potent. On the other hand, serum albumin of the AOM group of mice was significantly declined and treatment with either tested algal extracts noticeably ameliorated the diminished albumin levels.
AOM administration to mice significantly increased serum urea levels when compared to the normal control mice. Oral supplementation of T. ornata extract markedly decreased the elevated serum urea when compared to the AOM control mice. Similarly, treatment of AOM-induced mice with P. pavonia significantly ameliorated serum urea level.
Serum uric acid showed a significant increase following AOM administration. Treatment of AOM-administered mice with P. pavonia extract significantly improved serum uric acid levels when compared to AOM control mice. T. ornata supplementation ameliorated serum uric acid levels, however, the decrease is non-significant compared to AOM control mice. Mice administered AOM showed a significant, increase in serum creatinine levels and both tested extracts produced a non-significant effect compared to the AOM group of mice.
Conclusion:
The current study suggests that T. ornata and P. pavonia, though their antioxidant and anti-inflammatory effects are able to attenuate colon and liver inflammation by downregulating NF-κB expression. Furthermore, the protective effects of both algae against AOM-initiated carcinogenesis were attributed, at least in part, to their ability to upregulate colonic PPARγ and p53 expression.