Investigation of the efficacy of bromelain treatment against methotrexate intoxication

Methotrexate (MTX) is an antimetabolite that antagonises folic acid metabolism by inhibiting various enzymes responsible for nucleotide synthesis. MTX blocks the synthesis of tetrahydrofolate, leading to the arrest of cell division and protein synthesis. With this effect, it is often used in cancer treatment to prevent the development of tumour cells. In addition, since the drug has immunosuppressive properties, it is also used in the treatment of diseases such as psoriasis and rheumatoid arthritis. Despite its widespread use, MTX treatment causes significant side effects such as hepatoxicity and nephrotoxicity. The most important reason for this is that MTX increases oxidative stress in the organism. Many antioxidant compounds are used to reduce the cytotoxic effect of MTX administration. In this study, it was tried to determine the effectiveness of bromelain (BRM) treatment against MTX induced nephrotoxicity. In the study, 42 female rats were used. The rats were randomly selected and divided into 6 groups. These groups were control, MTX, BRM20 (20 mg/kg/day BRM, p.o.), BRM40 (40 mg/kg/day BRM, p.o.), MTX+BRM20 (20 mg/kg/day BRM, p.o.) and MTX+BRM40 (40 mg/kg/day BRM, p.o.) groups, respectively. The study lasted for a total of 5 days. The control group was not treated and sacrificed at the end of the study. MTX, MTX+BRM20 and MTX+BRM40 groups were administered 20 mg/kg/i.p. single dose MTX on the first day of the study and sacrificed at the end of the study. In addition, all groups except the control and MTX groups were administered BRM orally at the indicated concentrations every day (for 5 days) throughout the study and sacrificed at the end of the study. At the end of the study, rats were anaesthetised, blood was collected by cardiac punction and kidney tissues were isolated. In serum samples, urea, creatinine and blood urea nitrogen were analysed using a commercial kit in an autoanalyzer. In the kidney tissues, malondialdehyde (MDA) level to determine lipid peroxidation, protein carbonyl levels to determine protein oxidation, 8-hydroxy deoxy guanosine (8-OH dG) level to determine DNA oxidation, Superoxide dismutase (SOD), catalase, glutathione peroxidase (GSH-Px) and glutathione reductase (GSH-Rx) activities and reduced glutathione (GSH) levels were measured to determine the antioxidant status and nitric oxide (NOx) and prostaglandin E2 (PGE2) levels were measured to observe the inflammatory response. In addition, the expression levels of interleukin 1-beta (IL-1β), tumour necrosis factor-alpha (TNF-α) and nuclear factor kappa beta (NF-κB) proteins in kidney tissue were examined by immunoblot method. The data obtained were expressed as mean±standard deviation and the data with a p value of 0.05 or less were considered statistically significant. One-way analysis of variance (ANOVA) and Tukey test were used for the evaluation of biochemical parameters. MTX administration impaired renal function tests, increased lipid peroxidation, protein and DNA oxidation and inflammatory response in renal tissue and weakened the antioxidant defence system. Bromelain administration prevented oxidative stress and inflammation in renal tissue. In conclusion, it was observed that MTX treatment caused damage in the renal tissue and bromelain administration could prevent the nephrotoxicity.