Stresses caused by ionizing radiation can also damage tissues and organs through the circulatory system. In this study, we aimed to determine the radioprotective effect of propolis, a natural and powerful antioxidant product, against oxidative liver damage caused by cranial irradiation. Thirty-two male albino Sprague–Dawley rats, divided into four groups, were designed as sham group, irradiation (IR) group, propolis plus IR, control group of propolis. Biochemical parameters were measured in liver tissue of rats. While Total enzymatic superoxide scavenging activity (TSSA) and non-enzymatic superoxide scavenging activity (NSSA), glutathione peroxidase (GSH-Px) activities of all groups were statistically significantly higher than rats receiving only-irradiation, Glutathione-S-transferase (GST) activity in the IR group was significantly lower than in the sham control group and IR + propolis group. Superoxide dismutase (SOD) activity in the IR group was found to be significantly higher than both the sham control group and the propolis control group, but lower than the IR + propolis group. Malondialdehyde level and xanthine oxidase activity were higher in the IR group than in the other groups. Compared to the sham control group, in the group treated with propolis, a significant elevation in antioxidant parameters, specifically TSSA, NSSA, SOD, and GST activities, was noted, with corresponding increases of 32.3%, 23.2%, 47.6%, and 22.6%, respectively. Our findings show that propolis can be a radioprotective agent against ionized radiation damage by increasing antioxidant activity and reducing oxidant stress in liver tissue.

In the realm of radiation oncology, the observation of the radiation-induced bystander effect (RIBE) has raised concerns about off-target tissue effects caused by radiation. The concept of RIBE encompasses the response of non-irradiated tissue to radiation exposure. This study investigated the impact of cranial irradiation on oxidative/nitrosative stress and inflammatory responses in liver tissue. Thirty-two male Sprague-Dawley rats were divided into four groups: sham, irradiation (IR), propolis plus IR, and propolis control. The IR group received an initial 1 ml oral dose of saline via an orogastric tube. Subsequently, the IR and IR plus propolis groups received a single dose of 5 Gy (Gy) gamma irradiation to the entire cranium. The IR plus Propolis Group received propolis (80 mg kg/day) via an orogastric tube one hour before IR, and this procedure was continued daily for 10 days. Liver tissue was analyzed for biochemical parameters at the study’s conclusion. In the IR group, total antioxidant status (TAS), total sulfhydryl groups (-SH) levels, paraoxonase (PON) and arylesterase (ARYL) activities were significantly diminished compared to all other groups, while nitric oxide synthase (NOS) activity, nitric oxide (NO^•), lipid hydroperoxide (LOOH), oxidative stress index (OSI), and total oxidant status (TOS) values were elevated. Conversely, ceruloplasmin (Cp) levels were markedly higher in the IR group than in the Sham and propolis control groups. These results suggest that propolis may serve as a radioprotective agent against radiation-induced bystander effects by enhancing antioxidant activity and mitigating oxidative/nitrosative stress in liver tissue.

Radiation-induced bystander effect (RIBE) contributes to oxidative and nitrosative stress in non-irradiated tissues following ionizing radiation (IR). This study investigated the protective effects of propolis and caffeic acid phenethyl ester (CAPE) against RIBE-mediated renal injury after total cranial irradiation in rats. Forty-eight male Sprague–Dawley rats were assigned to six groups: IR, IR + propolis, IR + CAPE, propolis control, CAPE control, and sham. A single 5 Gy cranial gamma irradiation was administered. Propolis (80 mg/kg/day, orally) and CAPE (10 μmol/kg/day, intraperitoneally) were given for 10 days. Renal antioxidant (SOD, GSH-Px, GST), oxidative (XO, MDA), and nitrosative (NOS, NO) parameters were evaluated. Multivariate analyses, including principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA), were performed. IR significantly decreased SOD activity and increased XO, MDA, NOS, and NO levels. Both propolis and CAPE effectively reversed these alterations, with propolis showing a more pronounced effect on oxidative stress markers. GSH-Px and GST activities remained unchanged. The findings suggest that propolis and CAPE attenuated oxidative/nitrosative changes in kidney tissue, consistent with a possible bystander-associated systemic response.

Background: This study aimed to evaluate the effect of tannic acid on colonic anastomosis in a sepsis model induced by cecal abrasion. Materials and methods: Thirty Sprague-Dawley rats were used. The animals were randomly divided into three groups of ten: Group 1 (n:10): Colonic anastomosis + 0.9% isotonic NaCl. Group 2 (n:10): Cecal ligation and puncture + Colonic anastomosis + 0.9% isotonic NaCl. Group 3 (n:10): Cecal ligation and puncture + Colonic anastomosis + Tannic Acid group. The rats were sacrificed on the fifth postoperative day, and the resected colon segments, bursting pressure, hydroxyproline levels, and histopathologic features of the anastomosis were evaluated. Results: The bursting pressure value was statistically significantly higher in Group 3, where tannic acid was administered (p < 0.05). Group 2 and Group 3, in which peritonitis was induced, had moderate levels of fibroblastic activity, inflammatory cell infiltration, neovascularisation, and collagen; whereas, they were higher in Group 1. Although the inflammation value dropped in Group 3 compared to Groups 1 and 2, there was no statistical difference in Group 2. The hydroxyproline values were 2.046 ± 1.1411 mcg/gr and 5.9730 ± 4.35900 mcg/gr tissues, respectively, in Groups 2 and 3, where septic conditions prevailed, and a statistically significant difference was found (p < 0.05). Conclusion: This experimental study revealed that the use of tannic acid during anastomosis has a positive effect on wound healing, acting through higher colonic anastomotic bursting pressures and higher tissue hydroxyproline levels.