Oxidative Stress and Its Consequences in the Blood of Rats Irradiated with UV: Protective Effect of Cannabidiol

Abstract

UVA/UVB radiation disturbs the redox balance of skin cells, and metabolic consequences can be transferred into the blood and internal tissues, especially after chronic skin exposure to UV radiation. Therefore, the aim of this study was to evaluate the effect of cannabidiol (CBD), an antioxidant and anti-inflammatory phytocannabinoid, on oxidative stress and its consequences in the blood of nude rats whose skin was exposed to UVA/UVB radiation for 4 weeks. It was shown that CBD penetrated the blood and in UVB-irradiated rats was preferentially located in the membranes of polymorphonuclear leukocytes, which promoted reduction of ROS generation and up-regulation of antioxidant ability by increasing the activity of glutathione reductase and thioredoxin reductase, while the level of reduced glutathione decreased by UV radiation. Consequently, reduction in UV-induced lipid peroxidation, assessed as 4-hydroxynonenal (4-HNE) and 8-isoprostane (8-isoPGF2α) as well as protein modifications, estimated as 4-HNE-protein adducts and protein carbonyl groups, was observed. CBD, by countering the UV-induced down-regulation of 2-arachidonylglycerol, promoted its antioxidant/anti-inflammatory effects by reducing CB1 and increasing PPARγ receptor activation and consequently ROS and TNF-α down-regulation. The results suggest that CBD applied topically to the skin minimizes redox changes not only at the skin level, but also at the systemic level.

Keywords: UV radiation; antioxidant therapy; blood plasma; cannabidiol; endocannabinoids; in vivo model; lipid peroxidation; nude rats; oxidative stress; polymorphonuclear leukocytes (PMNs).

Figure 1

The level of CBD in blood plasma and PMNs (cytosol and membranes fraction) of nude rats in the following groups: treated with CBD (every 12 h) for 4 weeks; irradiated with UVA (every 48 h) and treated with CBD (every 12 h) for 4 weeks. irradiated with UVB (every 48 h) and treated with CBD (every 12 h) for 4 weeks. The mean values for six rats in each group ± SD are shown: x—differences vs. CBD group, p < 0.05; a—differences vs. UVA + CBD treated group.

Figure 2

ROS levels in nude rat whole blood and PMNs in the following groups, in the following groups: control; treated with CBD (every 12 h) for 4 weeks; irradiated with UVA (every 48 h) for 4 weeks; irradiated with UVA (every 48 h) and treated with CBD (every 12 h) for 4 weeks; irradiated with UVB (every 48 h) for 4 weeks; irradiated with UVB (every 48 h) and treated with CBD (every 12 h) for 4 weeks. The mean values for six rats in each group ± SD are shown: x—differences vs. control group, p < 0.05; b—differences vs. UVB treated group, p < 0.05.

Figure 3

The activity of superoxide dismutase (Cu, Zn-SOD) as well as the level of thioredoxin (Trx) and the activity of thioredoxin reductase (TrxR) in the blood plasma of nude rats in the following groups: control; treated with CBD (every 12 h) for 4 weeks; irradiated with UVA (every 48 h) for 4 weeks; irradiated with UVA (every 48 h) and treated with CBD (every 12 h) for 4 weeks irradiated with UVB (every 48 h) for 4 weeks; irradiated with UVB (every 48 h) and treated with CBD (every 12 h) for 4 weeks. The mean values for six rats in each group ± SD are shown: x—differences vs. control group, p < 0.05; a—differences vs. UVA treated group, p < 0.05; b—differences vs. UVB treated group, p < 0.05.

Figure 4

The level of glutathione (GSH) and the activity of the GSH-dependent enzymes (glutathione peroxidase (GSH-Px) and glutathione reductase (GSSG-R) in the blood plasma of nude rats, in the following groups: control; treated with CBD (every 12 h) for 4 weeks; irradiated with UVA (every 48 h) for 4 weeks; irradiated with UVA (every 48 h) and treated with CBD (every 12 h) for 4 weeks; irradiated with UVB (every 48 h) for 4 weeks; irradiated with UVB (every 48 h) and treated with CBD (every 12 h) for 4 weeks. The mean values for six rats in each group ± SD are shown: x—differences vs. control group, p < 0.05; a—differences vs. UVA treated group, p < 0.05; b—differences vs. UVB treated group, p < 0.05.

Figure 5

The level of vitamins E, A, C in the blood plasma of nude rats in the following groups: control; treated with CBD (every 12 h) for 4 weeks; irradiated with UVA (every 48 h) for 4 weeks; irradiated with UVA (every 48 h) and treated with CBD (every 12 h) for 4 weeks; irradiated with UVB (every 48 h) for 4 weeks; irradiated with UVB (every 48 h) and treated with CBD (every 12 h) for 4 weeks. The mean values for six rats in each group ± SD are shown: x—differences vs. control group, p < 0.05.

Figure 6

The level of NF-κB (p52) and product of its transcriptional activity—TNF-α as well as phospho-Nrf2 (p68) and product of its transcriptional activity—HO-1 in nude rats PMNs in the following groups: control; treated with CBD (every 12 h) for 4 weeks; irradiated with UVA (every 48 h) for 4 weeks; irradiated with UVA (every 48 h) and treated with CBD (every 12 h) for 4 weeks; irradiated with UVB (every 48 h) for 4 weeks; irradiated with UVB (every 48 h) and treated with CBD (every 12 h) for 4 weeks. The mean values for six rats in each group ± SD are shown: x—differences vs. control group, p < 0.05; a—differences vs. UVA treated group, p < 0.05; b—differences vs. UVB treated group, p < 0.05.

Figure 7

The level of 8-isoPGF_2α and 4-HNE in the blood plasma of nude rats in the following groups: control; treated with CBD (every 12 h) for 4 weeks; irradiated with UVA (every 48 h) for 4 weeks; irradiated with UVA (every 48 h) and treated with CBD (every 12 h) for 4 weeks; irradiated with UVB (every 48 h) for 4 weeks; irradiated with UVB (every 48 h) and treated with CBD (every 12 h) for 4 weeks. The mean values for six rats in each group ± SD are shown: x—differences vs. control group, p < 0.05; a—differences vs. UVA treated group, p < 0.05; b—differences vs. UVB treated group, p < 0.05.

Figure 8

The level of 4-HNE-protein adducts and protein carbonyl groups (CBO) in the blood plasma of nude rats in the following groups: control; treated with CBD (every 12 h) for 4 weeks; irradiated with UVA (every 48 h) for 4 weeks; irradiated with UVA (every 48 h) and treated with CBD (every 12 h) for 4 weeks; irradiated with UVB (every 48 h) for 4 weeks; irradiated with UVB (every 48 h) and treated with CBD (every 12 h) for 4 weeks. The mean values for six rats in each group ± SD are shown: x—differences vs. control group, p < 0.05; a—differences vs. UVA treated group, p < 0.05; b—differences vs. UVB treated group, p < 0.05.

Figure 9

Endocannabinoids level AEA and 2-AG in the blood plasma of nude rats in the following groups: control; treated with CBD (every 12 h) for 4 weeks; irradiated with UVA (every 48 h) for 4 weeks; irradiated with UVA (every 48 h) and treated with CBD (every 12 h) for 4 weeks; irradiated with UVB (every 48 h) for 4 weeks; irradiated with UVB (every 48 h) and treated with CBD (every 12 h) for 4 weeks. The mean values for six rats in each group ± SD are shown: x—differences vs. control group, p < 0.05; a—differences vs. UVA treated group, p < 0.05; b—differences vs. UVB treated group, p < 0.05.

Figure 10

Endocannabinoids receptors expression CB1, CB2 and PPARγ in the PMNs of nude rats in the following groups: control; treated with CBD (every 12 h) for 4 weeks; irradiated with UVA (every 48 h) for 4 weeks; irradiated with UVA (every 48 h) and treated with CBD (every 12 h) for 4 weeks; irradiated with UVB (every 48 h) for 4 weeks; irradiated with UVB (every 48 h) and treated with CBD (every 12 h) for 4 weeks. The mean values for six rats in each group ± SD are shown: x—differences vs. control group, p < 0.05; a—differences vs. UVA treated group, p < 0.05; b—differences vs. UVB treated group, p < 0.05.