Abstract:

Ｏｂｊｅｃｔｉｖｅ：To investigate the effects of mitophage on macrophage polarization in rats with DN.
Ｍｅｔｈｏｄｏｌｏｇｙ：In vivo, DN model rats were established by intraperitoneal injection with streptozocin (STZ). Rats were sacrificed respectively at 8w、12w、18w、24w for histological and molecular analysis. In vitro, RAW2647 cells were cultured with 30 mM glucose with or without mitophage inhibitor (3MA) and activator (rapamycin) intervention. Mitophagyrelated proteins expression of LC3, Beclin1, p62, VDAC, iNOS (M1 marker) and MR (M2 marker) were detected by immunofluorescence and Western Blot.
Ｒｅｓｕｌｔｓ：Macrophage phenotype and mitophage had no obvious change in renal tissue of DN at 8th weeks. However, macrophages were exhibited to M1 phenotype at 12 weeks after induction of DN and displayed a lower level of mitophagy. Additionally, iNOS expression was positive correlated with the p62 expression (r=0894, P<005), while negative correlated with LC3 (r=-0617, P<005). Electronic microscopic analysis showed mitochondria swelling, crista decrease and lysosome reduction in DN rats compared with NC rats. Moreover, RAW2647 macrophages switched to M1 phenotype under high glucose conditions. Meanwhile, mitophagy was downregulated in such high glucose induced M1 macrophages. Furthermore, macrophages expressed more iNOS and lower MR when impaired mitophagy by 3MA. Rapamycin could significantly blocke highglucose induced iNOS and enhance MR expression.

Ｃｏｎｃｌｕｓｉｏｎ：
Mitophage may participate in the regulation of M1/M2 macrophage phenotype in diabetic nephropathy.

Key words: mitophage, macrophage, M1/M2 phenotype, diabetic nephropathy