Deshbhratar Shantaj M., Mahaley Jyotsna A., Raut Sonali R., Hile Vijay K. and Bhiwgade Dayanand A
The present investigation deals with the holistic information & knowledge of the interhaemal membrane of the megachiropteran bat, Cynopterus sphinx gangeticus during early (trilaminar, neural groove) & full-term stages of development. The morphology and histology of the definitive placenta of Pteropodidae bat, Cynopterus comprised of a discoidal, symmetrical and labyrinthine with haemodichorial condition. The orientation of the embryonic mass of the blastocyst was mesometrial and the attachment of the blastocyst being circumferential along with superficial attachment. The ultra-structural studies on the interhaemal membrane reflected that, initially the placenta was endotheliochorial in origin with the presence of maternal endothelium that persisted till the neural groove stage. The maternal endothelium was well-developed with large irregularly shaped blood lacunae which beared a unicellular layer of endothelial cells and later eroded & the maternal blood space came in direct confluence with syncytiotrophoblast. Free-floating amoeboid-shaped cells were also noted in the Maternal Blood Space. The interstitial membrane became highly inconspicuous by the subsequent developing stage. Most uniquely the intrasyncytial lamina was absent and later noticed only at few sites as a double-layered discontinuous membrane with homogenous maternal inside during the full-term stage. As such the conventional history of conversion of the interstitial membrane into intra-syncytial lamina did not hold true in this case. Occasional “Blebbing” or ballooning of the intra-syncytial lamina was also noted. The cytotrophoblast immensely vacuolated and sometimes it was such greatly attenuated at sites that it resembled a haemomonochorial condition with the presence of only syncytiotrophoblast. Certain binucleate cytotrophs or Giant cells were also observed. The confirmative absence of maternal endothelium and the presence of syncytio & cytotrophoblast at full-term stage resolved that the placenta is haemodichorial and thus the ambiguity of it being haemomonochorial or haemodichorial is finally resolved.
