Fig. 5.

a–j Representative transmission electron micrographs from female CD-1 mice necropsied at 26 week of age following transplacental exposure to vehicle, AZT, 3TC or AZT/3TC on days 12–18 of gestation. a (20,000×): Control mouse cardiac muscle; mitochondria have representative sizes, cristae numbers, matrix density; b (25,000×): representative clusters of enlarged mitochondria seen occasionally in control mouse cardiac muscle. c, d 3TC-exposed mouse cardiac muscle; c (20,000×): increased numbers of mitochondria with reduced cristae numbers, increased metrical granularity; d (30,000×): enlarged mitochondria with reduced matrix density, cristae numbers, a few mitochondria have marked reduction in cristae numbers; sarcomeres have markedly reduced myofilament and Z-line density and increased myofilament and Z-line disorganization. e, f (30,000×): AZT-exposed mouse cardiac muscle. e mitochondria have reduced numbers, marked size variation, reduced matrix density and cristae numbers; sarcoplasm is increased with increased granularity; sarcomeres have markedly reduced myofilament and Z-line density and increased myofilament and Z-line disorganization; f enlarged mitochondria have moderate loss of matrix density; sarcomeres have reduced myofilament and Z-line density. g, j AZT/3TC-exposed mouse cardiac muscle; g (30,000×): mitochondria have increased matrix density, cristae have increased density; sarcomeres have reduced myofilament and Z-line density; h (30,000×) enlarged mitochondria have dense matrices and cristae; sarcomeres have multi-focal areas of disorganization of myofilaments and Z-lines; i (15,000×): mitochondria have markedly reduced cristae numbers, increased metrical granularity; j (30,000×): a single markedly enlarged mitochondrion with markedly reduced cristae numbers and a length equivalent to approximately five sarcomeres; sarcomeres have multifocal disorganization of Z-lines