This study aims to evaluate the genetic basis and activity of
lecithin cholesterol acyltransferase (LCAT) in a novel Mongolian gerbil model for
hyperlipidemia. Gerbils may be susceptible to high fat and
cholesterol (HF/HC) diets, which can rapidly lead to the development of
hyperlipidemia. Approximately 10-30% of gerbils that are over 8months old and fed controlled diets spontaneously develop
hyperlipidemia. Using the HF/HC diet model, we detected
triglycerides (TG), total
cholesterol (TC), HDL (
high density lipoprotein)-C,
LDL (
low density lipoprotein)-C and LCAT in both old (>8months) and young gerbils. The TC and HDL-C levels were two times higher in old gerbils compared with young gerbils (P<0.01). However, in the old group the LCAT activity fell slightly compared with the normal
lipidemia group. It is reasonable to hypothesize that this may be associated with single nucleotide polymorphisms of the LCAT gene. We cloned this gene to investigate the sensitivity of the gerbil to the HF/HC diet and spontaneous
hyperlipidemia. The entire LCAT gene was cloned by splicing sequences of RACE (rapid amplification of
cDNA ends) and nest-PCR products (AN: KC533867.1). The results showed that the 3683base pair gene consists of six exons and five introns. The LCAT
protein consists of 444
amino acid (AA) residues, which are analogous to the human LCAT gene, and includes 24
signal peptide AA and 420 mature
protein AA. Expression of LCAT was detected in the kidney, spleen and adrenal tissue, apart from the liver, by immunohistochemistry. The abundance of the
protein was greater in the older group compared with the control group. Polymorphisms were analyzed by PCR-SSCP (PCR-single-strand conformation polymorphism) but none were found in 444 animals of the ZCLA closed population (a Chinese cultured laboratory gerbil population).