Adiponectin protects rat heart from left ventricular remodeling induced by chronic intermittent hypoxia via inhibition of TGF-β/smad2/3 pathway.

OBJECTIVE: Obstructive sleep apnea syndrome (OSAS) is associated with many cardiovascular disorders. Chronic intermittent hypoxia (CIH) is the primary player in OSAS of the many associated factors. This study was in order to investigate the effects of the Adiponectin (Ad) on left ventricular remodeling induced by CIH.

METHODS: Forty-five rats were randomly divided into three groups: normal control (NC) group, CIH group and CIH plus Ad supplemented (CIH + Ad) group. After 35 days' CIH exposure, masson analysis was used to detect the left ventricular fibrosis and western blot was used to measure the protein expression of collagen I, collagen III and TGF-β/smad2/3 pathway. Gene analysis by RT-PCR was used to study the MMP2 and TIMP2.

RESULTS: After CIH exposure, the fibrosis of left ventricular in CIH group was significantly remarkable than that in both NC and CIH + Ad groups (P<0.05), although statistical difference existed between NC and CIH + Ad groups (P<0.05). In addition, the protein expression of collagen I as well as collagen III and the ratio of mRNA levels of MMP2/TIMP2 were the highest in CIH group but the lowest in NC group, with CIH + Ad group in between. There was a significant difference among three groups (all P<0.05). The TGF-β/smad2/3 pathway was activated obviously in CIH group, but less noticeably in CIH + Ad group (P<0.05) with a significant difference in the two groups.

CONCLUSIONS: The present study showed that Ad could ameliorate the left ventricular remodeling induced by CIH via inhibition of the expression of TGF-β/smad2/3 pathway.