P-171 Poster of distinction

Early pancreas transplantation improves the motor nerve conduction in sciatic and caudal nerves of alloxan-induced diabetic rats

C.T. Spadella¹, S. Alberti¹, A.N. Lucchesi¹, L.A. Resende^2
1 School of Medicine of Botucatu, Surgery and Orthopaedics, Botucatu, Sao Paulo State, Brazil; ² School of Medicine of Botucatu,Neurology, Botucatu, Sao Paulo State, Brazil

Objective: To assess the temporal relationship between successfully pancreas transplantation (PT) and the course of diabetic neuropathy we studied electrophysiological recordings from the nerves of transplanted rats in 3 different stages after surgery.

Methods: 150 inbred male Lewis rats were randomly assigned to 5 experimental groups with 30 rats each: NC – non-diabetic controls; DC – untreated diabetic controls, and PT1, PT2, PT3 – diabetic rats that received syngeneic pancreas transplants 4, 12 and 24 wks after alloxan diabetes induction, respectively. Each group was further divided into 3 subgroups with 10 animals, and laboratory and nerve conduction studies were prospectively recorded in all rats at 1, 3, and 6 mo after surgery.

Results: DC rats showed sustained hyperglycemia and increased glicosylated hemoglobin levels throughout the experiment (P<0.001). Recorded responses from the sciatic and caudal nerves showed significantly diminished amplitude (AMPL) and increased temporal dispersion of compound muscle action potencials (CMAPs) in DC when compared to NC rats after 1, 3 and 6 mo of follow-up (P<0.05). AMPL of CMAPs was reduced by 40% in DC recordings in these periods. Motor nerve conduction velocity (MNCV) also was slower and distal latency (DLAT) longer in nerves of DC rats after these periods (P<0.05). Rats underwent PT up to 4 and 12 wks after diabetes onset had significant (P<0.05) improvement of all electrophysiological abnormalities when compared with DC rats after 1, 3, and 6 mo after transplants. Nevertheless, AMPL and MNCV as well as dispersion of CMAPs and DLAT remained altered in PT rats when procedure was performed later (24 wks) in all periods of follow-up.

Conclusions: Our results suggest that may exist a “point of no return” of diabetic neuropathy where control of glycemia no more reverts the nerve electrophysiological abnormalities (Research supported by FAPESP).

P-171 Poster of distinction

Early pancreas transplantation improves the motor nerve conduction in sciatic and caudal nerves of alloxan-induced diabetic rats

C.T. Spadella¹, S. Alberti¹, A.N. Lucchesi¹, L.A. Resende^2
1 School of Medicine of Botucatu, Surgery and Orthopaedics, Botucatu, Sao Paulo State, Brazil; ² School of Medicine of Botucatu,Neurology, Botucatu, Sao Paulo State, Brazil

Objective: To assess the temporal relationship between successfully pancreas transplantation (PT) and the course of diabetic neuropathy we studied electrophysiological recordings from the nerves of transplanted rats in 3 different stages after surgery.

Methods: 150 inbred male Lewis rats were randomly assigned to 5 experimental groups with 30 rats each: NC – non-diabetic controls; DC – untreated diabetic controls, and PT1, PT2, PT3 – diabetic rats that received syngeneic pancreas transplants 4, 12 and 24 wks after alloxan diabetes induction, respectively. Each group was further divided into 3 subgroups with 10 animals, and laboratory and nerve conduction studies were prospectively recorded in all rats at 1, 3, and 6 mo after surgery.

Results: DC rats showed sustained hyperglycemia and increased glicosylated hemoglobin levels throughout the experiment (P<0.001). Recorded responses from the sciatic and caudal nerves showed significantly diminished amplitude (AMPL) and increased temporal dispersion of compound muscle action potencials (CMAPs) in DC when compared to NC rats after 1, 3 and 6 mo of follow-up (P<0.05). AMPL of CMAPs was reduced by 40% in DC recordings in these periods. Motor nerve conduction velocity (MNCV) also was slower and distal latency (DLAT) longer in nerves of DC rats after these periods (P<0.05). Rats underwent PT up to 4 and 12 wks after diabetes onset had significant (P<0.05) improvement of all electrophysiological abnormalities when compared with DC rats after 1, 3, and 6 mo after transplants. Nevertheless, AMPL and MNCV as well as dispersion of CMAPs and DLAT remained altered in PT rats when procedure was performed later (24 wks) in all periods of follow-up.

Conclusions: Our results suggest that may exist a “point of no return” of diabetic neuropathy where control of glycemia no more reverts the nerve electrophysiological abnormalities (Research supported by FAPESP).