Changes in Lipids Containing Long- and Very Long-Chain Polyunsaturated Fatty Acids in Cryptorchid Rat Testes1

Abstract

The aim of the present study was to examine the effects of experimental cryptorchidism on rat testicular phospholipids and neutral lipids that contain long-chain (C(18)-C(22)) and very long-chain (VLC) (C(24)-C(32)) polyunsaturated fatty acids (PUFA). The weight of the cryptorchid testis was nearly half that of the contralateral control at postsurgical Days 7-10 owing to the depletion of germ cells. Concomitantly, the amounts of major glycerophospholipids (GPL) and sphingomyelin (SM) per testis decreased. Both these lipids lost their characteristic long-chain and very long-chain PUFA, notably 22:5n-6 and 28:4n-6, respectively, which suggests that these species are linked to the membranes of germ cells. In contrast, the amounts and concentrations of triglycerides (TG; triacylglycerols and 1-O-alkyl-2,3-diacylglycerols) and cholesterol esters (CE) increased several fold in the surviving cells (mainly Sertoli cells) in the cryptorchid testis. All these neutral lipids, but especially CE, accumulated large amounts of the major PUFA of the testis, 22:5n-6, as well as pentaenes with longer carbon chains (i.e., 24:5n-6 in TG and 28:5n-6 in CE). This accretion suggests that neutral lipids may store preformed PUFA coming from dying germ cell GPL and also VLCPUFA no longer needed as a source of PUFA destined to assemble new germ cell GPL. The lipid adjustments observed in cryptorchidism suggest a possible role for Sertoli cell CE in the turnover and conservation of PUFA within seminiferous tubules.

Altered Lipid Homeostasis in Sertoli Cells Stressed by Mild Hyperthermia

“…phagocytosis, intracellular lipid transport, or metabolism, were temporarily disturbed by these exposures. This delay sharply contrasted with the results of experimental cryptorchidism [9]. In this case, the increase in neutral lipids levels occurred at much faster rates and then decreased, all in the time frame of a few days.…”

“…Previous work from our laboratory showed that, in vivo , the heat-stressed rat testis undergoes an intense depletion of lipids that are exclusive of germ cell membranes, as shown after experimental cryptorchidism [9] and after experimental hyperthermia [10]. In both models, glycerophospholipids (GPL) rich in long-chain polyunsaturated fatty acids (PUFA) like 20:4n-6 and 22:5n-6, and sphingomyelins (SM) rich in very long chain PUFA (VLCPUFA) like 28:4n-6 and 30:5n-6, disappeared as the last mature germ cells abandoned the testis and seminiferous tubules became almost exclusively populated by SC.…”

Biosynthesis of very long-chain fatty acids (C>24) in Atlantic salmon: Cloning, functional characterisation, and tissue distribution of an Elovl4 elongase

“…Salmon Elovl4 showed high efficiency in the elongation of C20 and C22 PUFA substrates that led to the production of n-3 and n-6 polyenes containing up to C36. The VLC-PUFA are FA uniquely found in specific lipid molecules of retina (Alvedaño, 1987(Alvedaño, , 1988), brain (Robinson et al, 1990), and testis (Furland et al, 2003(Furland et al, , 2007aZadravec et al, 2011).…”

Transient Scrotal Hyperthermia Induces Lipid Droplet Accumulation and Reveals a Different ADFP Expression Pattern between the Testes and Liver in Mice

“…Recently, it has been demonstrated in vitro that lipid β-oxidation is a major pathway for the production of ATP, and that phagocytosis of apoptotic spermatogenic cells increases ATP production and lipid droplet accumulation in the Sertoli cells of mouse testes [36]. In cryptorchid rat testes, which could be considered as hyperthermic, the amount and concentration of triglycerides and cholesterol esters increased several fold [37]. In the current study, we found that transient scrotal hyperthermia induced lipid droplet accumulation in murine testes.…”