Conclusion
Melittin may offer protection against kidney injury, probably by regulating podocyte autophagy. These results provide the theoretical basis for applying melittin in CRF therapy.
Methods
A 5/6 nephrectomy model (5/6 Nx) of renal failure was established on rats for in vivo assays, and mouse podocyte clone 5 (MPC5) mouse podocyte cells were treated with angiotensin II (AngII) to establish an in vitro podocyte damage model. The 24-h urine protein, serum creatinine, and blood urea nitrogen levels were evaluated after one, 2, and 4 weeks. Hematoxylin and eosin staining, Masson staining, and periodic acid-Schiff staining were used to examine the pathological changes in kidney tissues. A cell counting kit 8 assay was used to assess the cell viability. Reverse transcription polymerase chain reaction and Western blot were used to assess the mRNA and protein levels in the cells, respectively.
Results
In the rat 5/6 Nx, melittin reduced the 24-h urinary protein excretion and the serum creatinine and blood urea nitrogen levels. Furthermore, the renal pathology was improved in the melittin-treated 5/6 Nx rats. Melittin promoted podocin, nephrin, Beclin 1, and the LC3II/LC3I ratio and inhibited phosphorylated mammalian target of rapamycin (mTOR)/mTOR in 5/6 Nx-induced rats and AngII-induced MPC5 mouse podocyte cells. Moreover, inhibiting autophagy with 3-MA weakened the effects of melittin on podocin, nephrin, and the LC3II/LC3I ratio in podocytes.