Effects of cadmium exposure on medaka (<i>Oryzias latipes</i>) testes

Abstract

Adult male medaka (Oryzias latipes) were exposed to 10 ppm of cadmium for 96 h, and the testes were examined histopathologically. Numerous apoptotic cells were found in the spermatogonia and spermatocytes at 72 and 96 h after initiation of cadmium exposure, and the pyknotic index, TUNEL-positive rate, and cleaved caspase-3-positive rate in the spermatogonia and spermatocytes of the cadmium-treated group were higher compared with the control group. No significant difference between the control and cadmium-treated groups was found in the phospho-histone H3-positive rate in the spermatogonia and spermatocytes. No edematous, hemorrhagic, or necrotic changes were observed within the testes in the cadmium-treated group. These results suggest that spermatogonia and spermatocytes in medaka testes are highly sensitive to cadmium. Exposure to 10 ppm of cadmium induced histopathologic changes in the testes that were similar to those described in rodents exposed to low doses of cadmium.

Effects of cadmium exposure on Iberian ribbed newt (<i>Pleurodeles waltl</i>) testes

“…The results of the present study revealed that a 50 mg/kg exposure to cadmium induces significant apoptosis of spermatogonia and spermatocytes in the testes of adult Iberian ribbed newts, indicating that germ cells in these differentiation stages are highly sensitive to cadmium. The histopathologic findings of the present study are similar to those reported for cadmium-exposed frogs, such as B. melanostictus and R. hexadactyla Lesson , and fish, such as O. latipes 24 , 25 , 26 . To our knowledge, this is the first report of the histomorphologic characteristics of cadmium-induced testicular dysfunction in newts.…”

“…injection of 50 mg/kg of cadmium induced apoptosis of the spermatogonia and spermatocytes in Iberian ribbed newts. The observed histopathologic findings in the testes of newts exposed to cadmium were similar to those reported for testes of several frogs, such as Bufo melanostictus and Rana hexadactyla Lesson 24 , 25 , and fish, such as Oryzias latipes 26 .…”

Mechanisms of Cadmium-Induced Testicular Injury: A Risk to Male Fertility

“…Cadmium-induced testis showed increased activity of caspase 3 and 9, which increases the number of morphological signs of apoptosis, including chromatin decondensation and marginalization in primary spermatocytes, loss of the nuclear envelope in the spermatogonium, disruption of mitochondrial membrane potential (MMP), degradation of cytoplasmic organelles, and DNA distribution [ 102 ]. The testicles of rats [ 103 ], fish [ 104 ], and lizard [ 105 ] all showed evidence of cadmium-induced spermatogonia and spermatocyte apoptosis. The concentration-dependent effect of cadmium on human embryonic germ cell apoptosis was revealed by immune signaling detection of caspase 3 in testicular tissue [ 106 ].…”

Cadmium as a testicular toxicant: A Review

“…Various morphological characteristics of apoptosis, eg, chromatin condensation and marginalization in primary spermatocytes, degeneration of cytoplasmic organelles, disappeared nuclear envelope in spermatogonium, and fragmentation of DNA were observed in Cd‐intoxicated testes of freshwater crab ( Sinopotamon henanense ), along with increased activities of caspase‐3 and ‐9 in a concentration‐dependent manner (Wang et al, 2011). Other morphological and ultrastructural studies have also reported Cd‐induced apoptosis of spermatogonia and spermatocytes in rodents (Boujelben, Abdennabi, Guermazi, & Elfeki, 2018; Niknafs et al, 2015), fish (Hirako, Takeoka, Furukawa, & Sugiyama, 2017) and newt (Hirako et al, 2017) testis, respectively. A concentration‐dependent effect of Cd on apoptosis of human fetal germ cells was illustrated by immunohistochemical detection of caspase‐3 in testicular tissue under in vitro conditions (Angenard et al, 2010).…”