[Pharmacological studies on chemical protectors against radiation. II. Influence of x-irradiation on body weight of mouse]

Protective effect of dendrodoine analog, an aminothiazole derivative against X-radiation induced hepatocellular damage in mice

This study evaluated the radioprotective effect of dendrodoine analog (DA) against radiation-induced damage in the liver of mice. The study was divided into two phases; in the first phase, the effective concentration of DA was fixed by performing a survival study. In the second phase, the fixed effective concentration of DA was orally administered to mice to evaluate its radioprotective efficacy by performing various assays. The results indicated that the radiation-induced decrease in the activities of antioxidant enzymes, increase in thiobarbituric acid reactive substances (TBARS) and comet parameters were altered by pre-administration with the effective concentration of DA which restored the antioxidant status to near normal and decreased the level of the TBARS and comet parameters. The histopathological examinations further confirmed the hepatoprotective effect of DA in mice. Thus, the current study showed DA to be an effective radioprotector against radiation induced damage in the liver of mice.

Prophylactic effect of flaxseed oil against radiation-induced hepatotoxicity in mice

Flaxseed (linseed, Linum usitatissimum, Linaceae) is widely used for its edible oil in many parts of the world. The present study investigates the radioprotective and antioxidative potential of flaxseed oil (FO). Swiss albino mice were administered FO orally once daily for 15 consecutive days, then exposed to a single dose of 5 Gy of gamma radiation. Lipid peroxide, reduced glutathione and total protein were estimated in the liver. Aspartate aminotransferase (AST), alanine aminotransferase (ALT), acid and alkaline phosphatase estimations in serum were also carried out. Radiation-induced increases in the levels of lipid peroxidation (LPO), AST, ALT and acid phosphatase were significantly ameliorated by flaxseed oil pretreatment, and radiation-induced depletion in the level of glutathione (GSH) and alkaline phosphatase activities was significantly inhibited by flaxseed oil administration. The lifespan was increased in the flaxseed oil treated irradiated mice in comparison with their respective control mice, with survival data showing an LD(50/30) (lethal dose for 50% of animals after 30 days) of 7.1 and 10 Gy for control and FO treated irradiated mice, respectively, and produced a dose reduction factor for flaxseed oil (DRF) of 1.40. Radiation-induced deficits in body and organ weight were significantly reduced or prevented in flaxseed oil pretreated mice. The protection afforded by flaxseed oil may be attributed to the constituents of the oil, which include omega-3 essential fatty acids and phytoestrogenic lignans, which appear to play an important role in free radical scavenging and singlet oxygen quenching. The study does not rule out the possibility of a prophylactic potential of flaxseed oil against radiation-induced degenerative changes in liver.

Evaluation of radioprotective effects of Rajgira (Amaranthus paniculatus) extract in Swiss albino mice

The radioprotective efficacy of aqueous extract of Rajgira (Amaranthus paniculatus) leaves against whole body gamma radiation was studied in Swiss albino mice. The oral administration of Rajgira extract at 800 mg/kg body weight/day for 15 consecutive days before whole body exposure to radiation was found to be effective with the LD50/30 values of 6.33 and 8.62 Gy for irradiation alone and Rajgira+irradiation group, respectively, giving a dose reduction factor of 1.36. This effect of Rajgira accompanied the increased endogenous spleen colonies and the spleen weight without any side effect or toxicity, as well as the modulation of the radiation-induced decrease of reduced glutathione and the radiation-induced increase in lipid peroxidation assessed in the liver and the blood.

Modulatory influence of Adhatoda vasica Nees leaf extract against gamma irradiation in Swiss albino mice

The radiomodulatory influence of ethanolic extract of Adhatoda vasica Nees leaf extract against radiation-induced hematological alterations in peripheral blood of Swiss albino mice was studied at various post-irradiation intervals between 6 h to 30 days. Oral administration of A. vasica leaf extract (800 mg/kg body weight) prior to whole body irradiation showed a significant protection in terms of survival percentage and hematological parameters. Mice exposed to radiation (8.0 Gy) without A. vasica leaf extract pre-treatment exhibited signs of radiation sickness like anorexia, lethargicity, ruffled hairs and diarrhoea and such animals died within 25 days post-irradiation. The dose reduction factor (DRF = 1.6) for A. vasica leaf extract was calculated from LD50/30 values. A significant decline in hematological constituents (RBCs, WBCs, Hb and Hct) was evident till day 15 and no animal could survive beyond day 25. Conversely, animals pre-treated with A. vasica leaf extract showed 81.25% survival till 30 days after exposure and a gradual recovery was noted in the hematological values. However, these hematological values remained significantly below the normal even till day 30. A significant decrease in blood reduced glutathione (GSH) content and increase in lipid peroxidation (LPO) level was observed in control animals (Radiation alone). However, A. vasica leaf extract pretreated irradiated animals exhibited a significant increase in GSH content and decrease in LPO level. A significant increase in the serum alkaline phosphatase activity and decrease in acid phosphatase activity was observed in A. vasica leaf extract pretreated irradiated animals during the entire period of study.

Study on pre-treatment of melatonin against radiation-induced oxidative stress in mice

Antioxidants are part of the primary cellular defense against radiation-generated free radicals. Reports on low-level chronic administration of melatonin with its antiradiation influence are scanty. Although compelling logic suggests that melatonin may be effective for a variety of disorders, the mode and optimal dose of melatonin are still not clear. Most studies have used doses of supraphysiological blood levels. Present investigation reported that pre-treatment with the lower concentration of melatonin (0.1mg/kg b.w./day) for 15 consecutive days affords potential protective effect against radiation-induced oxidative stress and mortality in mice. Radiation-induced augmentation in the levels of lipid peroxidation, glutathione disulphide (GSSG) and acid phosphatase was significantly ameliorated by melatonin pre-treatment. Radiation-induced depletion in the level of reduced glutathione (GSH), as well as glutathione peroxidase (GSH-Px) and alkaline phosphatase activities, was inhibited significantly by melatonin administration. Regression analysis of survival data yielded LD(50/30) as 7.16 and 11Gy for control (irradiation alone) and experimental (melatonin-treated irradiated) mice, respectively, and produced a dose reduction factor (DRF), 1.53. Radiation-induced deficit in the body and organ weight also got inhibited significantly in the melatonin pre-treated mice. The findings support property of melatonin as a free radical scavenger and singlet oxygen quencher and indicate the antioxidative properties of melatonin against the gamma radiation.

Radioprotection of Swiss albino mice by plant extract Mentha piperita (Linn.)

The oral administration of Mentha extract (ME) before exposure to gamma radiation was found to be effective in increasing the frequency of radiation-induced endogenous spleen colonies. A significant increase in the weight of the spleen was observed in animals of the Mentha and radiation combined group in comparison to the irradiation-alone group on day 10 of postirradiation. Furthermore, a significant increase in the body weight of animals in the Mentha and radiation combined group was observed in all the radiation doses studied. A regression analysis of survival data yielded LD50/30 as 6.48 +/- 0.07 and 11.59 +/- 0.21 Gy for the irradiation-alone and the Mentha and radiation combined group, respectively, and produced a dose reduction factor (DRF) of 1.78. Significant increases in total erythrocyte and leucocyte counts, hemoglobin concentration, and hematocrit values were observed in the animals of the Mentha and radiation combined group in comparison to the hematological values observed in the irradiation-alone group at all radiation doses studied (6, 8, and 10 Gy). A dose-dependent decrease in reduced glutathione (GSH) content and an increase in lipid peroxidation (LPO) levels were observed in control animals. However, the animals of the Mentha and radiation combined group exhibited a significant increase in GSH content and a decrease in LPO level, but the values remained below normal. A significant increase in the serum alkaline phosphatase activity was observed in the animals of the Mentha and radiation combined group during the entire period of study, and normal range was evident at 24 h (6 Gy) and day 5 (8 Gy). However, this level could not be restored even at day 30 in 10 Gy exposed animals. Measured acid phosphatase activity in the animals of the Mentha and radiation combined group was found to be significantly lower than the respective controls and attained normal value at day 5 (6 and 8 Gy) and day 20 (10 Gy).

Radiomodulatory in?uence ofRajgira (Amaranthus paniculatus) leaf extract in Swiss albino mice

Radiomodulatory effect of Rajgira leaf extract against 6, 8 and 10 Gy gamma radiation has been evaluated by 30 day survival of Swiss albino mice. Animals of control groups (untreated irradiated) showed diarrhoea, ruffled hairs, epilation, facial edema and consistent decrease in body weight. These signs were less severe/absent in experimental groups (Rajgira treated irradiated), and recovery in body weight was also early and faster. Thirty day survivability was 66 per cent in control group, exposed to 6 Gy, whereas no animal survived beyond 14 and 10 days after irradiation with 8 and 10 Gy gamma rays respectively. However, 100, 60 and 25 percent survivability was observed in experimental groups at 6, 8 and 10 Gy respectively. Regression analysis of survival data showed that the LD50/30 values were 6.33 and 8.62 Gy for control and experimental animals respectively. The dose reduction factor (DRF) was computed as 1.36. A significant decrease in GSH content and increase in LPO level was observed in control animals, whereas in Rajgira pretreated irradiated animals the level of GSH was recorded significantly higher but LPO level decreased significantly. The results from the present study suggest that Rajgira pretreatment provide protection against gamma irradiation in mice.