Cell lines

Hela cells

Preparation Method

HeLa cells, labelled with 3H~thymidine (0.05 pic/ml, 1,850 mc/mM) for 20 hours,

Reaction Conditions

Cells were incubated with bleomycin A2 (8 or 40 μg/ml) for 6 hours at 37℃.

Applications

Bleomycin can cause the single-strand scission. The sulfhydryl compound is necessary for bleomycin A2 to cause scission in DNA strand as in the case of decreasing Tm of DNA. Unless EDTA was added to the cell suspension, more marked scission of DNA was demonstrated. The enhancement of DNA degradation seemed to occur during the extraction procedure.

Animal models

D1CC×D1BC tg mice，bred on a DBA/1J background

Preparation Method

Bleomycin was mixed with an equal amount of microbubbles (Ultrasound Contrast Agent SV-25) and administered via the i.t. route by a spray nebulizer (40 μl/mouse, 1.28 mg/kg body weight) before sonoporation on the chest by 1.0 W/cm2 for 1 min (Sonitron GTS Sonoporation System). Mice were anesthetized with isoflurane and the chest hair was shaved for sonoporation.

Dosage form

0.512 mg/ml in normal saline

Applications

Bleomycin is most commonly used to develop pulmonary fibrosis in animal models. In animal models, administration of single or multiple doses of bleomycin by either intra-tracheal (i.t.) instillation, osmotic pump, intravenous route, or intranasal delivery induces pulmonary fibrosis, results in significant dose-dependent mortality.

• Allergol Immunopath 50.2 (2022): 104-114.

Bleomycin is produced by Streptomyces verticillis. The Bleomycin molecule has two main structural components; a bithiazole component which partially intercalates into the DNA helix, parting the strands, as well as pyrimidine and imidazole structures, which bind iron and oxygen forming an activated complex capable of releasing damaging oxidants in close proximity to the polynucleotide chains of DNA. This may lead to chain scission or structural modifications leading to release of free bases or their propenal derivatives. It has potent tumor killing properties which have gained it an critical role in cancer chemotherapy. It causes little marrow suppression, but the major adverse is pulmonary toxicity effect.^[1]

In vitro, Bleomycin reacts with DNA which has previously been treated with a sulfhydryl compound, and cause a decrease in its melting temperature (Tm). In the reactions in vitro, strand scission in DNA has been confirmed which indicate that in the presence of a sulfhydryl compound in vitro, Bleomycin binds to DNA, and causes single-strand scission. The scission of DNA may be the cause of the inhibition of thymidine incorporation into DNA of growing cells and the inhibition of cell division.^[2]

In vivo study demonstrated that Bleomycin-induced pulmonary toxicity and fibrosis could be significantly affected by Soluble epoxide hydrolase (sEH) inhibitors AUDA. In vivo, AUDA significantly improved Bleomycin -induced decline in lung function and body weight, and inhibited inflammatory cell accumulation and the mRNA and protein expression of interleukin (IL)-1β, TGF-β1, and matrix metalloproteinase 9 (MMP-9) in lung tissue.^[3]

References:
[1]. John H. et al. Mechanisms of Bleomycin-induced lung damage. Arch Toxicol (1991) 65:81-94.
[2]. Suzuki H, et al. On the mechanism of action of Bleomycin: scission of DNA strands in vitro and in vivo. J Antibiot (Tokyo). 1969 Sep;22(9):446-8.
[3]. Xin-wei D, et al. Soluble epoxide hydrolase inhibitor AUDA decreases Bleomycin-induced pulmonary toxicity in mice by inhibiting the p38/Smad3 pathways. Toxicology 389 (2017) 31–41.