Evaluation of Dysmorphogenesis in Embryonic Kidney Induced by Calcium Channel Blockers

Polycystic kidney disease is a common inherited disorder, characterized by formation of multiple fluidfilled cysts in kidney culminating into progressive renal failure. Abnormal proliferation of tubular epithelial cells consequent to genetic mutations associated with PKD1 gene together with disruption in calcium (Ca 2+ )i homeostasis is the hallmark of cystic epithelium. In this regard we sought to exploit microscopy as a tool to assess the ultra-structural alterations both at surface and organelle level. Cystogenesis was induced in mouse metanephroi, (embryonic day, E13.5) using 8-bromocyclic 3’5’-cyclic adenosine monophosphate (8-BrcAMP). Phase contrast microscopy exhibited numerous dilated tubules in metanephroi which continued to enlarge for five days in culture. The effects of 8-Br-cAMP on renal tubular epithelium/cyst epithelium were assessed by histopathological and electron microscopic analysis. Transmission electron microscopy revealed ultra-structural changes like increased vacuolation, swollen and deformed mitochondria, chromatin condensation and disrupted cell membrane in tubular epithelial cells of 8-Br-cAMP treated metanephroi as compared to control. Exposure to Ca 2+ channel blockers, nifedipine and gadolinium, further augmented 8-BrcAMP induced tubular dilations as assessed by histopathological and ultra-structural examinations. Calcium channel brokers augment cAMP induced cystogenesis, possibly through mitochondrial alterations.