REGENERATION OF TACTILE LAMELLAR CORPUSCLES OF THE RAT AFTER POSTNATAL FREEZE INJURY

Tactile lamellar corpuscles were studied after freeze injury of rat to e pads under normal conditions and following permanent denervation in 1- to 65-day-old animals In the innervated skin, digital corpuscles re differentiated in all age groups examined during development and matur ation. Characteristic of the reinnervated skin was a great diversity i n the shape and size of newly formed corpuscles. Small corpuscles with only 1-3 lamellae around their terminals and well-developed corpuscle s of about normal size with up to 15 lamellae were sometimes found wit hin the same sample of skin. The regenerated corpuscles were reduced i n number; they reappeared in only 50% of dermal papillae in the toe pa ds after freeze injury in 7-week-old rats, compared with approximately 100% of dermal papillae that contained lamellar corpuscles in normal toe-pad skin. In denervated toes, occasional corpuscular lamellar stru ctures appeared first after freeze injury applied to 34-day-old rats. In the toe pads denervated and injured by freezing in 42- and 49-day-o ld rats, lamellar structures redifferentiated in 10% of the papillae, and in 23.5% after freeze in about jury applied to 3-month-old rats. U nsatisfactory preservation of basal laminae at the former sites of the corpuscles and in the acellular peripheral nerve stumps, and/or insuf ficient migration of Schwann cells, may be responsible for the absence or abortive regeneration of lamellar structures in denervated skin of food pads after freeze injury in young rats.