Restoration of trimethyltin induced hippocampal degeneration by single and multiple transplantation

Trimethyltin produces a selective loss of pyramidal neurons in the hippocampus resulting in functional deficits. The present study was aimed to assess the comparative restoration of behavioural and neurochemical deficits in trimethyltin chloride (7.5 mg/Kg body weight, i.p) treated rats following single or multiple site fetal hippocampal transplants. Exposure to trimethyltin caused a decrease in learning ability (51 %), an increase in locomotor activity (92 %) and decrease in acetylcholinesterase activity (36%) and muscarinic receptor binding (31%). Trimethyltin treated rats receiving multiple transplants of fetal hippocampal cell suspension (0.25 μl at 8 stereotaxic coordinates) showed significant restoration of the functional deficits 4 weeks post transplantation. This restoration by multiple site transplants persisted upto 16 weeks post transplantation. Restoration of the above deficits by single site transplants (2 μl at a single coordinate), 4 weeks post transplantation was less marked in comparison to multiple transplants and was evident only in learning ability and muscarinic receptor binding after 16 weeks of transplantation. The results suggest that multiple site transplants provide better restoration , on long term basis, in chemical induced neurodegeneration.