Intervention Effects Of SAA On Atheroselerosls In ZDF Rats And Research Of The Related Anti-inflammatory Mechanism

Objective To observe the intervention effects of SAA on atheroselerosls in ZDF rats and study inhibition effects of SAA on inflammation reaction and NLRP3 inflammasome during the plaque formation period for exploring the mechanism of SAA resisting atherosclerosis,which can support theoretical basis and experimental basis for SAA preventing and treating cardiovascular disease.Methods 24 male ZDF rats of 8-week old were taken.After 4 weeks’ high-fat diets continuously feeding,ZDF rats were divided into 4 groups according to weights,fasting blood-glucose and blood lipids.The 4 groups included model group(NS 5mL/kg),low-dose SAA group(SAA 0.5 mg/kg),high-dose SAA group(SAA 1 mg/kg)and positive group(ATV 5mg/kg),and another 6 male ZL rats of the same weeks as normal group.Except for normal group,other groups were given 6.0×104 IU/kg VD3 by intraperitoneal injection(injecting 3 times every 3 days)for inducing type 2 diabetes mellitus complicated with early atherosclerosis animal model in ZDF rats.The rats were given the corresponding drugs per day at the same day until to the 6th week.Normal group was fed with commom diets,and the rest were fed with high-fat diets.Fasting blood-glucose,blood lipid and hsCRP content were tested after 0,2,4,6 weeks of administration.Glycated hemoglobin and insulin levels in serum were detected at the 0th and 6th of administration,and atherosclerosis index,insulin resistance index and insulin sensitive index were calculated.Serum inflammatory mediators,adhesion factor and lipid peroxidation levels were detected after 6 weeks of administration.The rats were killed after anesthesia and aortic roots were used for HE staining to observe process of atherosclerosis.The states of aortic macrophage infiltration were observed by immunohistochemical staining.RT-PCR and Western Blot were for detecting mRNA and prorein expression of NLRP3 inflammasome and related proteins respectively,such as TLR4,NLRP3,Caspase-1,NF-κB and IL-1β.Results:(1)Compared to the normal group,blood glucose,HbAlc and insulin were significantly rised(P<0.05).Both blood glucose and insulin in drug groups weren’t decreased notably(P>0.05),but HbAlc level in High-dose SAA group was notably lower than model group after 6 weeks of administration(P<0.05).(2)Compared to the normal group,CHOL,TG,LDL-C and HDL-C were significantly increased in model group(P<0.05).CHOL and LDL-C were remarkably reduced during 4-6 weeks and TG was remarkably reduced at 6th week in High-dose SAA group(P<0.05).In addition,AI in model group was obviously higher than normal group(P<0.05),which was significantly decreased in Low-dose SAA group and High-dose SAA group(P<0.05).(3)Aortic roots of model group rats formed typical early atherosclerosis plaque,comapanied with foam cell aggregating and calcification partly.But it was improved in different degrees in low-dose and high-dose SAA.(4)Difference of hsCRP wasn’t observed between model group and normal group before modeling(0 week)(P>0.05),whereas it was notably increased during 2～6 weeks and it in low-dose SAA and high-dose SAA was significantly lower than model group after 4～6 weeks’ administration(P<0.05).Adhesion molecules and chemokine were obviously rised in model group(P<0.05),while all of them were decreased significantly after 6-week’ administration of SAA(P<0.05).(5)Compared to normal group,SOD in serum of model group was notably decreased and ox-LDL and MDA content were notably increased(P<0.05).After drug administration,ox-LDL in low-dose and high-dose SAA was reduced(P<0.05)and SOD in high-dose SAA was increased(P<0.05).(6)Expression difference of toll-like receptor 4 among groups wasn’t significantly observed(P>0.05).Expression levels of NLRP3,cleaved caspase-1,p-NF-κB、IL-1β were notably rised(P<0.05).P-NF-κB and IL-1β were decreased in low-dose group(P<0.05),and NLRP3,schizolytic caspase-1,p-NF-κB and IL-1β were also notably reduced in high-dose SAA(P<0.05).Conclusions:(1)Type 2 diabetes mellitus complicated with atheroselerosls of ZDF rats model can be induced successfully by high-fat diets combined with VD3 intraperitoneal injection.(2)SAA has the function of resisting atheroselerosls formation in ZDF,which may be associated with phamacological effects of reducing blood fat,anti-oxidation and anti-inflammatory.(3)SAA can obviously inhibit expression of NLRP3 inflammasome and related,inflammatory factors,suggesting that functional mechanism of SAA of reducing inflammation response may be through inhibiting expression of NLRP3 inflammasome,and therefore retards atherosclerosis formation.