Ceramides with 2-hydroxylated, very long-chain polyenoic fatty acids in rodents: From testis to fertilization-competent spermatozoa.
Sphingolipids from rodent testis and spermatozoa are known to contain non-hydroxylated (N-) and 2-hydroxylated (2-OH) very-long-chain polyunsaturated fatty acids (VLCPUFA). In this study, the contribution of species with each type of fatty acids to the total ceramides (Cer) and sphingomyelins (SM) was investigated in rat and mouse testis and in rat spermatozoa. The major VLCPUFA in both lipids of testis were N- and 2-OH versions of 28:4n-6, 30:5n-6 and 32:5n-6 in the rat, and predominantly of 30:5n-6 in the mouse. Absent altogether from rat pre-puberal testes, SM and Cer with N-VLCPUFA appeared 10 days earlier than those with 2-OH VLCPUFA in postnatal development, in association with germ cell differentiation. Conversely, in adult fertile rats that were gradually deprived of germ cells in vivo after treatment with doxorubicin, SM and Cer with N-VLCPUFA decreased earlier than their 2-OH counterparts, and neither was present in aspermatogenic testes. In rat epididymal spermatozoa, the content of Cer prevailed over that of SM and 2-OH VLCPUFA prevailed over N-VLCPUFA in both lipids. In mature gametes, the acrosomal reaction resulted in an almost complete hydrolysis of the species of SM that contain both types of VLCPUFA to produce the corresponding Cer. Ceramides are biosynthetic precursors of SM in the testis, but themselves final products in spermatozoa. VLCPUFA-rich SM and Cer are thus produced in germ cells with the teleological objective of fulfilling their ultimate physiological role in spermatozoa that are apt and ready to fertilize an oocyte.
Zanetti
Samanta R
SR
Instituto de Investigaciones Bioquímicas de Bahía Blanca, Consejo Nacional de Investigaciones Científicas y Técnicas and Universidad Nacional del Sur, 8000 Bahía Blanca, Argentina.
de Los Ángeles Monclus
María
M
Rensetti
Daniel E
DE
Fornés
Miguel W
MW
Aveldaño
Marta I
MI
D020101:Acrosome Reaction / Q000502:physiology; D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D002518:Ceramides / Q000032:analysis*; D002855:Chromatography, Thin Layer; D004317:Doxorubicin / Q000494:pharmacology; D005231:Fatty Acids, Unsaturated / Q000032:analysis*; D005260:Female; D005306:Fertilization; D008055:Lipids / Q000737:chemistry; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D051381:Rats; D017208:Rats, Wistar; D013075:Sperm Capacitation / Q000502:physiology; D013094:Spermatozoa / Q000737:chemistry* / Q000502:physiology; D013109:Sphingomyelins / Q000032:analysis*; D013737:Testis / Q000737:chemistry* / Q000166:cytology / Q000187:drug effects; D013997:Time Factors
D000903:Antibiotics, Antineoplastic; D002518:Ceramides; D005231:Fatty Acids, Unsaturated; D008055:Lipids; D013109:Sphingomyelins; D004317:Doxorubicin