Patatin-like phospholipase domain containing 5 (PNPLA5) is a neotype neutral lipase with dual activity of anabolism and catabolism in vitro and in vivo, which has a low mRNA expression level in humans and mice.  PNPLA5, which is localized to lipid droplets and required for efficient autophagy by optimal initiation, has been speculated to possess triglyceride hydrolase activity, and has been associated with low density lipoprotein cholesterol (LDL-C).  Above all, PNPLA5 is a relatively new gene, which is reported less about its biological function research, especially the function research in the rats is still blank.  In this study, we examined the spatiotemporal expression profile of PNPLA5 and found that it was expressed at low levels in most organs of Sprague Dawley (SD) rats, but was present at very high levels in the skin and testes.  To further determine the biological function of PNPLA5 in mammals, we generated PNPLA5-knockout SD rats using the clustered regularly-interspaced short palindromic repeats (CRISPR)/Cas9 system.  PNPLA5-null rats were viable, but showed a variety of phenotypic abnormalities, such as abnormal bleeding, and varied hematobiochemical parameters including increased serum total cholesterol (TC), triglycerides and high density lipoprotein cholesterol (HDL-C) level, and reduced LDL-C level, compared with wild-type control rats.  These data are consistent with an important role for PNPLA5 in lipid metabolism, providing a new target gene and animal model for treatment of cardiovascular diseases in the future.

Skin grafting has been used as one of the most reliable tests to determine the genetic stability of laboratory animal such as mice and rats inbred line, but no identification of swine inbred lines by skin grafting has been reported. At present, Wuzhishan miniature pig (WZSP) inbred line has acquired the F24 individuals in China. In order to verify whether WZSP inbred line had been cultivated successfully, allogeneic skin grafts and related research were performed on F20 individuals of WZSP inbreeding population, compared with a control group of autologous transplantation. We observed the transplant recipients’ wounds, detected peripheral blood-related indicators interleukin-2, 4 and 10, CD4+ and CD8+ lymphocytes, and conducted hematoxylin-eosin (HE) and Masson’s staining of skin to judge whether the immune rejection reactions occurred within 28 days after transplantation. Chr. 7 genomic heterozygosity of 48 WZSP individuals from F20 to F22 was analyzed by high-density single nucleotide polymorphism (SNP) chips (60 000 SNPs). The result showed that there were no significant differences in graft skin, the plasma interleukin-2, 4, 10, CD4+ and CD8+, HE and Masson’s staining results between the allograft and autograft groups, and no immune rejection occurred on the allograft group. We found that 11 genes in Chr. 7 of major histocompatibility complex (MHC) I and MHC II were homozygous which confirmed that immune antibody of the allograft and autograft groups were highly identical and also provided a theoretical basis to no immune rejection occurred on the allograft in the inbred WZSP. The result proved that the WZSP inbred line had been cultivated successfully for the first time in the world. The test methods also provide a scientific basis for the identification of swine and mammal inbred lines.