Objective: This study aimed to investigate the effects of kefir supplementation on blood glucose regulation and renal Toll-like receptor (TLR-2 and TLR-4) expression in a rat model of diabetes, providing insights into the potential anti-inflammatory mechanisms of probiotic-fermented foods.

Material and Method: Thirty-five rats included in the study were randomly assigned to four groups: control (C), kefir-treated (K), diabetic (D), and kefir-treated diabetic (DK). To prevent hyperglycemia-related complications, D and DK rats received 1–3 units/day of insulin aspart according to uniform clinical criteria, while K and C groups received no insulin. Blood glucose levels of the rats were measured, after which they were sacrificed, and their kidneys were collected and stored at −80°C to preserve tissue integrity. And then rat kidneys were analyzed. RNA was extracted and reverse-transcribed to cDNA. Quantitative real-time PCR was performed to assess TLR-2 and TLR-4 expression.

Results: In diabetic rats, blood glucose levels were significantly elevated compared to the control group (D group: 460 ± 61.3 mg/dL; C group: 96.8 ± 10.2 mg/dL, p < 0.001). Kefir supplementation significantly reduced glucose levels in the DK group (DK group: 291.1 ± 44.2 mg/dL; compared to the D group, p < 0.001), whereas no significant difference was observed between the C and K groups (p = 0.441). Renal expression of TLR-2 and TLR-4 was markedly upregulated in diabetic rats (p <0.001), with TLR-2 and TLR-4 expression significantly attenuated following kefir treatment (p <0.001).

Conclusion: Kefir supplementation reduces blood glucose and renal TLR-2 and TLR-4 gene expression in diabetic rats, highlighting its therapeutic potential against diabetic nephropathy.

Kefir Experimental diabetes mellitus Blood glucose Rat kidney TLR-2 and TLR-4 gene expression