Developmental sequence of events of fore-limb in DDY mouse embryo were observed to obtain the data on shape ; on histology with special reference to the apical ectodermal ridge(AER), programmed cell death(PCD) and chondro-osteogenesis and ; on
changes
of glycoconjugates.
Fore-limb buds appeared between the day 9.5 and 10 of gestation(plug day=0) and distal ends grew into paddle-like plates from day 11, plates condensed to form digital rays on day 12, webbed fingers on day 13 and fingers were separated on day 14.
Well developed AER appeared with the beginning of elevation of buds and decreased in size from day 11 and remained remnants on day 12.5 of gestation. Proximal core mesenchyme began to condense form day 11 and transformed to precartilaginous zone
12
hours later, chondrified from day 12.5 and ossified from day 15 and these phenomena proceeded proximo-distal sequence. Programmed cell death happened only between the day 10.5 to 11.5 and were confined to the proximal and middle zone of
mesenchyme,
which comes into question how PCD in metioned area and time correlate with subsequent morphogenses.
PAS positive reactivity was gradually increased in the epithelium, AER and cartilaginous zone with the development proceed but that of mesenchyme was weak throughout the period, and in comparison with PAS reactivity, PAPS reactivity to the
epithelium
was always less but no difference in cartilaginous zone which suggest that amount and component of glycoconjugates are variable and tissue / stage-specific in the developing limb.
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