Vitamin - a and limb regeneration in stages of the egyptian toad, bufo regularis Reuss-histological study

Abstract

The histogenesis of regenerated limbs, of both control and treated /larvae/ with 30 I.U./ml of retinol palmitate for 3 days, was studied in two larval stages (viz. stages 53 & 54) of the anuran amphibian, Bufo regularis Reuss. Some histological changes took place in the amputated limbs of treated larvae in two phases: (a) during treatment and (b) after cessation of treatment and thereafter. In (a): the wound epidermal superficial layer became corrugated, basement membrane was not discernible, local haemorrhage was extensive and blastema call accumulation was inhibited. In (b): the epidermal surface maintained its irregularity for some days and contained numerous large vocuolated cells. Also, cells from the dedifferentiated stump tissues underwent active proliferation leading to the establishment of a large blastema, particularly in the case of the earlier stage. Cellular condensations in these blastemas were mostly unevenly distributed; they appeared more closely packed together posteriorly than anteriorly along the antero-posterior axis. Histological observations concerning blastema cells and theair active proliferation after cessation of treatment, were confirmed quantitatively through the blastema volume in both stages.

اختص هذا البحث بدراسة تاثيرفيتامين "ألما على تجدد الطرف الخلفي لطورين يرقيين للعلجوم المصري (برمائيات لاذيلية) وذلك بعمل فحرص نسيجية لكل من يرقات مجموعة ضابطة دس قات مجموعة معالجة بفيتامين "أ" (تركيز 30 وحدة دولية/ملليلتما لمدة ثلاثة أيام بعد البترعند منتسف المساق .