Progetto MeSi 2-Effetti a lungo termine sulla funzione immune dell'assunzione di THC in adolescenza: meccanismi e valutazione dei fattori di rischio per patologie immunomediate nell'adulto.
Project ~~Cannabis use has characteristics of very early onset, and it is known that more than 25% of teens have used this substance during their life. Among the many consequences related to the use of cannabis it has been recently shown that THC, as well as endogenous cannabinoids, can affect immune system function. The main objective of this study is to investigate whether the use of cannabis in adolescence would cause effects on the immune system that can persist overtime, even in adulthood.
As immune parameters, we evaluated both the innate and the acquired immunity, measuring
T cells and macrophage cytokine production. We used Balb C / J male mice 33 days of age, which corresponds to human adolescence, and 80 day old mice as adults.
The effects induced by THC on the immune system was investigated using two different dose regimens :1) starting from 5 mg/kg s.c. and gradually reaching 15 mg /kg in 10 days
2) starting from 5 mg/kg s.c and gradually reaching 25 mg/kg in 10 days. The first dosing can be comparable to the plasma THC concentration that can be measured in human heavy smokers while the second protocol comprises higher doses hard to be reached in the human.
Control mice of the same age were treated with vehicle alone for the same period. Some groups of animals were sacrificed for immune measurements immediately after the end of the treatment, while other groups were left undisturbed until adulthood (80 days), when the immunological assessments were performed. In order to study acquired immunity, young and adult animals were immunized with the protein KLH to induce an antigen-specific reaction, similar to that obtained with the vaccination procedures in humans. Cytokine production by spleen cells was measured after in vitro KLH restimulation, by ELISA method.
Thelper1 / Theper2 cytokine balance was assessed by measuring the production of Th1 cytokines IL2 and IFNγ, and Th2 cytokine IL4. In order to assess macrophage function we used peritoneal macrophages stimulated in vitro with LPS. After 10 day THC repeated administration in both young and adult mice, a significant reduction in the production of IL2 and IFNγ was observed. On the contrary, the levels of IL4 were always significantly increased.
These data are consistent with the ability of THC to shift the Th1 / Th2 balance towards Th2. In order to identify the long-term THC effects, we measured immune response after immunization of adult mice that had been treated with THC for 10 days as adolescents.
In these animals we observed that the production of cytokines IL2 and IFNγ was still lower while also the IL-4 level was decreased compared with vehicle mice. Regarding the macrophage function, repeated administrations of THC in both young and adult mice induced a significant increase of IL10 while TNF increased. Particularly interesting were the results obtained in adult animals treated with THC in adolescence: in these animals we observed an opposite effect since IL10 decreased. Modulation of immune parameters was similar with both dose protocols, but the effects appeared to be more significant with the higher doses.
These results indicate that the levels of proinflammatory cytokines decrease in a
dose-response fashion in young and adult mice treated with THC, and this effect persists over time, whereas the anti inflammatory cytokines that are augmented when measured immediately after THC treatment are reduced in a long term perspective. In conclusion our data demonstrate that the immune system is profoundly altered by THC exposure during adolescence.
As immune parameters, we evaluated both the innate and the acquired immunity, measuring
T cells and macrophage cytokine production. We used Balb C / J male mice 33 days of age, which corresponds to human adolescence, and 80 day old mice as adults.
The effects induced by THC on the immune system was investigated using two different dose regimens :1) starting from 5 mg/kg s.c. and gradually reaching 15 mg /kg in 10 days
2) starting from 5 mg/kg s.c and gradually reaching 25 mg/kg in 10 days. The first dosing can be comparable to the plasma THC concentration that can be measured in human heavy smokers while the second protocol comprises higher doses hard to be reached in the human.
Control mice of the same age were treated with vehicle alone for the same period. Some groups of animals were sacrificed for immune measurements immediately after the end of the treatment, while other groups were left undisturbed until adulthood (80 days), when the immunological assessments were performed. In order to study acquired immunity, young and adult animals were immunized with the protein KLH to induce an antigen-specific reaction, similar to that obtained with the vaccination procedures in humans. Cytokine production by spleen cells was measured after in vitro KLH restimulation, by ELISA method.
Thelper1 / Theper2 cytokine balance was assessed by measuring the production of Th1 cytokines IL2 and IFNγ, and Th2 cytokine IL4. In order to assess macrophage function we used peritoneal macrophages stimulated in vitro with LPS. After 10 day THC repeated administration in both young and adult mice, a significant reduction in the production of IL2 and IFNγ was observed. On the contrary, the levels of IL4 were always significantly increased.
These data are consistent with the ability of THC to shift the Th1 / Th2 balance towards Th2. In order to identify the long-term THC effects, we measured immune response after immunization of adult mice that had been treated with THC for 10 days as adolescents.
In these animals we observed that the production of cytokines IL2 and IFNγ was still lower while also the IL-4 level was decreased compared with vehicle mice. Regarding the macrophage function, repeated administrations of THC in both young and adult mice induced a significant increase of IL10 while TNF increased. Particularly interesting were the results obtained in adult animals treated with THC in adolescence: in these animals we observed an opposite effect since IL10 decreased. Modulation of immune parameters was similar with both dose protocols, but the effects appeared to be more significant with the higher doses.
These results indicate that the levels of proinflammatory cytokines decrease in a
dose-response fashion in young and adult mice treated with THC, and this effect persists over time, whereas the anti inflammatory cytokines that are augmented when measured immediately after THC treatment are reduced in a long term perspective. In conclusion our data demonstrate that the immune system is profoundly altered by THC exposure during adolescence.