Aloe polysaccharides mediated radioprotective effect through the inhibition of apoptosis

Radiomodulatory effects of Aloe vera on hepatic and renal tissues of X-ray irradiated mice

The present study was aimed to explore the protective role of Aloe vera gel extract against hepatic and renal damage caused by X-ray exposure to mice. Male balb/c mice were divided into four groups: control, Aloe vera gel extract [AV] (50 mg/ kg b.w on alternate days for 30 days), X-ray (2 Gy) and AV + X-ray. X-ray irradiation enhanced the serum levels of liver function indices and chromosomal abnormalities in liver. Kidney function markers were found to be deranged and were accompanied by reduced glomerular filtration rate indicating renal dysfunction. Irradiation caused histopathological and biochemical alterations in both tissues which was associated with enhanced reactive oxygen species (ROS), lipid peroxidation (LPO) levels, lactate dehydrogenase (LDH) activity and enhanced apoptosis as revealed by TUNEL assay and DNA fragmentation. The administration of Aloe vera gel extract to X-ray exposed animals significantly improved their hepatic and renal function parameters which were associated with a reduction in ROS/LPO levels, LDH activity and chromosomal abnormalities as compared to their irradiated counterparts. In vitro assays revealed effective radical scavenging ability of Aloe vera gel extract, which may be linked to its potential in exhibiting antioxidant effects in in vivo conditions. This data suggested that Aloe vera may serve to boost the antioxidant system, thus providing protection against hepatic and renal damage caused by X-ray.

Protective role of Aloe vera against X-ray induced testicular dysfunction

The present investigation was carried out to evaluate the possible radioprotective potential of an Aloe vera extract against whole-body X-ray irradiation-induced testicular alterations in mice. Male balb/c mice were divided into four groups: control, A. vera, X-ray and A. vera pre-treated + X-ray irradiated. Histopathological examination revealed significant structural alterations in testes after X-ray exposure, which was also associated with the presence of apoptotic cells as assessed by TUNEL assay. X-ray irradiation resulted in elevation in the levels of reactive oxygen species, lipid peroxidation, a reduction in glutathione concentration and enhanced activities of antioxidant enzymes such as glutathione reductase, glutathione peroxidase, catalase, superoxide dismutase and glutathione-S-transferase. Sperm count/motility and testosterone levels were significantly decreased in the irradiated group. Irradiated animals pre-treated with A. vera extract revealed an improvement in antioxidant status, inhibition of lipid peroxides, apoptotic cell formation and enhanced testicular parameters when compared to the X-ray-exposed group. These findings suggest that A. vera extract could ameliorate X-ray-induced damage due to its free radical scavenging properties and its potential to boost cellular antioxidant defence machinery.

In vitro and in vivo protective effects of granulocyte colony-stimulating factor against radiation-induced intestinal injury

Intestinal injury is a major cause of death after high-dose radiation exposure. The use of granulocyte-colony stimulating factor (G-CSF) to treat radiation injury has focused on enhancing recovery from hematopoietic radiation syndrome. We evaluated G-CSF for its ability to protect against radiation-induced intestinal injury in rat intestinal epithelial cells (IEC-6) and BALB/c mouse models. For in vitro tests, pre-radiation addition of G-CSF to IEC-6 prevented cytotoxicity and the loss of cell viability. Pre-radiation G-CSF treatment also reduced radiation-induced cleavage of caspase-3 and p53 in IEC-6. For in vivo tests, examination 12 h after abdominal irradiation showed that G-CSF-treated mice were protected against apoptosis of the jejunal crypts. G-CSF-treated mice also showed attenuated intestinal morphological changes 3.5 days after abdominal radiation (10 Gy). G-CSF also reduced the levels of proinflammatory cytokines interleukin-6 and tumor necrosis factor-α after radiation. This study showed that G-CSF may protect against radiation-induced intestinal damage through its anti-apoptotic and anti-inflammatory effects. These results suggest that G-CSF is promising candidate for protection against intestinal mucosal injury following irradiation.

The synergistic effects of traditional Chinese herbs and radiotherapy for cancer treatment

Traditional Chinese medicine (TCM) has been demonstrated to have potent cytotoxic activity against certain malignant tumors. Ionizing radiation (IR) is one of the most effective methods used in the clinical treatment of cancer. The drawback of a single formula is that it limits the treatment efficacy for cancer, while comprehensive strategies require additional theoretical support. However, a combination of different antitumor treatment modalities is advantageous in restricting the non-specific toxicity often observed with an extremely high dose of a single regimen. The induction of apoptotic cell death is a significant process in tumor cells following radiotherapy or chemotherapy, and resistance to these treatments has been linked to a low propensity for apoptosis. Autophagy is a response of cancer cells to IR or chemotherapy, and involves the prominent formation of autophagic vacuoles in the cytoplasm. In this review, the synergistic effects of TCM and radiotherapy are summarized and the underlying mechanisms are illustrated, providing new therapeutic strategies for cancer.

Evaluation of radioprotective efficacy and possible mechanism of action of Aloe gel

The present study was undertaken to determine the optimum effective dose, dose reduction factor (DRF) and possible mechanism of action of Aloe gel. Three different doses of gel (250, 500 and 750 mg/kg body weight) were tested against 8 Gy induced damage in Swiss albino mice. A dose of 750 mg/kg body weight of Aloe was found the most effective while, 250 mg/kg body weight was the least effective in providing protection, as observed in the form of higher concentrations of blood GSH and vitamin C and lower level of serum LPO than irradiated animals at 1h post irradiation and higher percent of survivors up to day 30 post irradiation. Treatment of mice with Aloe before irradiation with different doses of gamma radiation (6-12 Gy) delayed the onset and reduced the severity of signs of radiation sickness. The LD(50/30) was calculated as 6.77 and 10 Gy for untreated irradiated and Aloe treated irradiated animals, respectively and its dose reduction factor was also calculated as 1.47. Aloe gel scavenged the free radicals, DPPH•, ABTS(+•) and NO in a concentration dependent manner in vitro and therefore, scavenging of free radicals seems to be its important mechanism of action.

Aloe vera oral administration accelerates acute radiation-delayed wound healing by stimulating transforming growth factor-β and fibroblast growth factor production

BACKGROUND

Delayed wound healing is a significant clinical problem in patients who have had previous irradiation. This study investigated the effectiveness of Aloe vera (Av) on acute radiation-delayed wound healing.

METHODS

The effect of Av was studied in radiation-exposed rats compared with radiation-only and control rats. Skin wounds were excised on the back of rats after 3 days of local radiation. Wound size was measured on days 0, 3, 6, 9, and 12 after wounding. Wound tissues were examined histologically and the expressions of transforming growth factor β-1 (TGF-β-1) and basic fibroblast growth factor (bFGF) were examined by immunohistochemistry and reverse-transcription polymerase chain reaction.

RESULTS

Wound contraction was accelerated significantly by Av on days 6 and 12 after wounding. Furthermore, the inflammatory cell infiltration, fibroblast proliferation, collagen deposition, angiogenesis, and the expression levels of TGF-β-1 and bFGF were significantly higher in the radiation plus Av group compared with the radiation-only group.

CONCLUSIONS

These data showed the potential application of Av to improve the acute radiation-delayed wound healing by increasing TGF-β-1 and bFGF production.

A new approach to postoperative peritoneal adhesions: prevention of peritoneal trauma by aloe vera gel

OBJECTIVE

Covering peritoneal surfaces with aloe vera gel may prevent peritoneal trauma and hence postoperative peritoneal adhesions.

STUDY DESIGN

Forty Wistar albino out-bred female rats (mean weight, 180+/-25 g; mean age, 6 months) were divided into four groups. In Group 1, 0.1 mL aloe vera gel was injected into the peritoneal cavities. In Group 2, peritoneal adhesions were induced. In Group 3, adhesions were induced and the modeled area was covered by 0.1 mL aloe vera gel. In Group 4, the area was covered with aloe vera gel prior to adhesion induction. The rats were sacrificed on postoperative day 10 and the adhesions were scored both microscopically and macroscopically.

RESULTS

The mean macroscopic adhesion score in the four groups was 0, 5.8+/-0.42, 5.2+/-0.79, and 1.1+/-1.2 respectively, with the difference between Group 4 and Groups 2 (p<0.001) and 3 (p<0.05) statistically significant. The mean histopathological fibrosis values were significantly higher in Group 3 than in Group 4 (2.6+/-0.51 vs 1.2+/-0.91, p=0.002).

CONCLUSION

Aloe vera gel can effectively decrease adhesion formation if applied before, but not after, after peritoneal trauma. This effect is likely due not to its chemical properties but to its viscosity, providing a covering to prevent peritoneal trauma.

Radioprotective effects of fucoidan on bone marrow cells: improvement of the cell survival and immunoreactivity

Fucoidan is a sulfated polysaccharide purified from brown algae including Fucus vesiculosus and has a variety of biological effects including mobilization of hematopoietic progenitor cells. Recently, we demonstrated that fucoidan stimulates the antigen-presenting functions of dendritic cells. In this study, we investigated the radioprotective effects of fucoidan on bone marrow cells (BMCs), which are the main cellular reservoir for the hematopoietic and immune system. To evaluate the effects of fucoidan, we assayed cell viability and immune responses. In a viability assay, fucoidan significantly increased the viability of BMCs. Based on the results of flow cytometric analysis, the increased viability of fucoidan-treated BMCs was attributed to the inhibition of radiation-induced apoptosis. Furthermore, fucoidan altered the production of immune-related cytokines from BMCs and increased the capability of BMCs to induce proliferation of allogeneic splenocytes. Taken together, our study demonstrated that fucoidan has radioprotective effects on BMCs with respect to cell viability and immunoreactivity. These results may provide valuable information, useful in the field of radiotherapy.

Modulation of apoptosis of eckol against ionizing radiation in mice

To investigate the radioprotective potential of eckol, a component of the seaweed Ecklonia cava, against radiation in vivo, we evaluated the effect of eckol on cyto- and histo-protective capability of the lymphocytes and intestine against damage induced by a single whole body irradiation (WBI) in vivo. Here, we ascertained that eckol protected the lymphocytes' viability and rescued intestinal cells from radiation-induced apoptosis by decreasing the amount of pro-apoptotic p53 and Bax and increasing that of anti-apoptotic Bcl-2. These findings indicate that the overexpression of anti-apoptotic protein, which may lead to resistance to DNA damage, is involved deeply in protection of gastrointestinal cells after irradiation. Thus, eckol that can protect cells and tissues against ionizing radiation may have considerable potential as adjuncts to successful radiotherapy.